4

GUIDE TO THE BOARD’S OPINION AND ORDER

The Board’s opinion is organized into the following main sections, beginning on the

pages indicated below:

Section Heading

Page

Table of Proposed and Current Dissolved Oxygen Standards

4

Procedural Matters

6

Illinois’ Current Dissolved Oxygen General Use Water Quality Standard

8

USEPA’s National Criteria Document

13

Introduction to the IAWA Proposal

14

Introduction to the DNR/IEPA Proposal

16

Overview of Responses to the DNR/IEPA Proposal

22

IAWA Proposal

24

Dissolved Oxygen Data

35

DNR/IEPA Proposal To Have Enhanced Dissolved Oxygen Standards for Designated

Stream Segments

49

DNR/IEPA Proposal to Include July in Early Life Stages

74

DNR/IEPA Proposal for a Narrative Standard

81

Dissolved Oxygen Saturation Versus Concentration

85

Proposed 6.5 mg/L Dissolved Oxygen

89

Implementation Concerns

90

Technical Feasibility and Economic Reasonableness

94

Conclusion

97

The Board’s opinion is followed by the Board’s order, which begins on page 98 of this

document and contains the rule amendments being proposed for first notice.

TABLE OF PROPOSED AND CURRENT DISSOLVED OXYGEN STANDARDS

For ease of reference and comparison, the Board sets forth below in table form the

dissolved oxygen levels as proposed by IAWA, as proposed jointly by DNR and IEPA, as set

forth in USEPA’s NCD, and as provided in the current Board regulations:

Time Period

1-day

minimum

*

7-day mean

minimum

**

7-day

mean

***

30-day

mean

****

IAWA Proposed Revisions to DO General Use Water Quality Standards (mg/L)

March through June

(early life stages)

5.0

6.0

July through February

(other life stages)

3.5

4.0

---

5

Time Period

1-day

minimum

*

7-day mean

minimum

**

7-day

mean

***

30-day

mean

****

DNR/IEPA Proposed Revisions to DO General Use Water Quality Standards (mg/L)

Level 1 (approx. 8% of General Use Stream Miles)

March through July

(early life stages)

5.0

6.25

August through February

(other life stages)

4.0

4.5

6.0

Level 2

March through July

(early life stages)

5.0

6.0

August through February

(other life stages)

3.5

4.0

5.5

Narrative Standard

Year-round

General use waters at all locations shall maintain sufficient

dissolved oxygen concentrations to prevent offensive

conditions as required in Section 302.203 of this Part.

Year-round

Quiescent and isolated sectors of General Use waters including

but not limited to wetlands, sloughs, backwaters and below the

thermocline in lakes and reservoirs shall be maintained at

sufficient dissolved oxygen concentrations to support their

natural ecological functions and resident aquatic communities.

USEPA NCD for DO (mg/L)

Warmwater

Early life stages (warmwater)

5.0

6.0

Other life stages (warmwater)

3.0

4.0

5.5

Coldwater

Early life stages (coldwater)

5.0

6.5

Other life stages (coldwater)

4.0

5.0

6.5

Current Illinois General Use Water Quality Standards for DO (mg/L)

16 hours of any 24-hour

period

Year-round

Anytime

6.0

5.0

*

Lowest value of DO measured during 24-hour calendar day

**

Arithmetic mean of daily DO minima from current and previous 6 calendar days

***

Arithmetic mean of daily mean DO values from the current and previous 6 calendar days

**** Arithmetic mean of daily mean DO values from the current and previous 29 calendar

days

Exh. 1; Exh. 2 (NCD); Exh. 20; Exh. 23, Figure 1, Table 1; PC 103 at 7-9; 35 Ill. Adm. Code

302.206.

---

6

PROCEDURAL MATTERS

Procedural History

On April 19, 2004, IAWA filed its rulemaking proposal to amend Illinois’ general use

water quality standard for dissolved oxygen.

2

The Board issued an order on May 6, 2004,

accepting the IAWA proposal for hearing. DNR and IEPA filed their joint proposed revisions to

the DO standard on April 4, 2006. Hearings concluded in November 2006 and public comments

were filed as recently as June 2007.

As Toby Frevert, Manager of the Division of Water Pollution Control for IEPA, testified,

Illinois’ general use dissolved oxygen standard carries more significance than

many of our other water quality standards and there is a wide diversity of opinion,

perspective and attitude among the various constituencies participating in the

proceeding. Exh. 14 at 2.

Given the significance of the DO general use water quality standard and the varied views

of the rulemaking participants on how it should be revised, the Board has accommodated the

wishes of the participants and allowed this rulemaking to proceed at a pace that would allow for

continued stakeholder discussions. To that end, the hearing officer scheduled hearings only

when the participants stated that they were ready to proceed and only after the hearing officer, at

the participants’ request, conducted six status conferences and received eight status reports over

the course of nearly two years.

The Board has held five public hearings over six days in this rulemaking: (1) June 29,

2004, in Chicago; (2) August 12, 2004, in Springfield; (3) August 25, 2005, in Chicago; (4) April

25, 2006, in Springfield; and (5) November 2-3, 2006, in Springfield. The following 20 persons

testified at the hearings indicated:

•

Dennis Streicher, Director of Water and Wastewater for the City of Elmhurst (first,

second, and third hearings, and fifth hearing);

•

John Callahan, Executive Director of the Bloomington and Normal Water Reclamation

District of McLean County (first and second hearings);

•

Dr. James Garvey, Associate Professor of Zoology and Associate Director of the

Fisheries and Illinois Aquaculture Center at Southern Illinois University (first, second,

and third hearings, and fifth hearing);

•

Roy Harsch, Drinker Biddle Gardner Carton, attorney for IAWA (first, second, and third

hearings, and fifth hearing);

•

Toby Frevert, Manager of the Division of Water Pollution Control for IEPA (all five

hearings);

2

The Board cites IAWA’s “statement of reasons” included in its rulemaking proposal as

“Statement at _.”

---

7

•

Dr. David Thomas, Chief of the Illinois Natural History Survey, DNR (second and third

hearings);

•

Mark Miller, Senior Policy Advisor for Lieutenant Governor Pat Quinn (second hearing);

•

Stan Yonkauski, Deputy Counsel with DNR’s Office of Legal Counsel (third hearing);

•

Albert Ettinger, attorney for Environmental Law & Policy Center, Prairie Rivers

Network, and Sierra Club (third hearing);

•

Todd Main, Director of Policy and Planning, Friends of the Chicago River (third

hearing);

•

Dr. Thomas Murphy, Professor

Emeritus

of Chemistry, DePaul University (third, fourth,

and fifth hearings);

•

Roy Smogor, a stream biologist in IEPA’s Surface Water Section (fourth and fifth

hearings);

•

Joel Cross, Acting Manager of the Watershed Protection Section within the Office of

Resource Conservation of DNR (fourth and fifth hearings);

•

Matthew Short with the Surface Water Section of IEPA (fourth hearing);

•

Ann Holtrop, Watershed Information Specialist with the Watershed Protection Section of

DNR (fourth hearing);

•

Richard Lanyon, General Superintendent of the Metropolitan Water Reclamation District

of Greater Chicago (fourth and fifth hearings);

•

Thomas Muth, District Manager, Fox Metro Water Reclamation District (fifth hearing);

•

Stephen Pescitelli, stream biologist with DNR (fifth hearing);

•

Louis Kollias, Director of the Department of Research and Development with the

Metropolitan Water Reclamation District of Greater Chicago (fifth hearing); and

•

Cindy Skrukrud, Clean Water Advocate for the Illinois Chapter of the Sierra Club (fifth

hearing).

The Board hearing officer accepted 41 hearing exhibits into the record. The hearing

exhibits are described in Appendix I to this opinion and order. Upon receipt, the transcripts of

the hearings were placed in the Clerk’s Office On Line (COOL) on the Board’s Web site at

www.ipcb.state.il.us

.

3

Many other documents from this rulemaking record are available through

COOL, including Board opinions and orders, hearing officer orders, and public comments.

The Board has received 111 public comments in this proceeding.

4

Those who filed

comments are listed in Appendix II to this opinion and order.

As required by Section 27(b) of the Act (415 ILCS 5/27(b) (2006)), the Board requested,

in a letter of May 11, 2004, that the Department of Commerce and Economic Opportunity

(DCEO) conduct an economic impact study (EcIS) for this rulemaking. In a letter of June 22,

2004, DCEO declined to perform an EcIS, noting its limited fiscal resources. When provided the

opportunity at hearing, no one testified about DCEO’s response. Tr.2 at 159.

3

Hearing exhibits are cited as “Exh. _ at _.” The hearing transcripts are cited as “Tr.1 at _” for

the first hearing, “Tr.2 at _” for the second hearing, “Tr.3 at _” for the third hearing, “Tr.4 at _”

for the fourth hearing, and “Tr.5 at _” for the fifth hearing.

4

Public comments are cited as “PC _ at _.”

---

8

Motions

On May 3, 2007, IAWA filed a motion for leave to avoid the requirement of serving the

dissolved oxygen monitoring data attached to its public comment, PC 109, filed on April 24,

2007. IAWA notes that the data are voluminous and that the entire filing, including the DO data,

is available on the Board’s website. There has been no response to IAWA’s motion, which the

Board grants.

See

35 Ill. Adm. Code 101.500(d).

On June 8, 2007, IEPA filed a motion for leave to file

instanter

a response to IAWA’s PC

109, attaching the response. IEPA filed the motion because under the Board’s procedural rules,

responses to motions are due within 14 days after service of the motion.

See

35 Ill. Adm. Code

101.500(d). IEPA’s response, however, does not address IAWA’s motion to avoid service of the

DO data attached to PC 109, but rather addresses the substance of IAWA’s public comment.

The Board therefore denies as unnecessary IEPA’s motion for leave and simply accepts IEPA’s

response as a public comment, PC 110.

Public Comments

First-notice publication in the

Illinois Register

of these proposed rule changes will start a

period of 45 days during which anyone may file public comments with the Board at:

Office of the Clerk

Pollution Control Board

James R. Thompson Center

100 W. Randolph Street, Suite 11-500

Chicago, Illinois 60601

The Board encourages persons to file public comments on the proposed amendments. Docket

R04-25 should be indicated on the public comment. Any person may file a public comment,

regardless of whether the person has yet filed one.

Additionally, public comments in this rulemaking may be filed through COOL at

www.ipcb.state.il.us.

Any questions about electronic filing should be directed to the Clerk’s

Office at (312) 814-3629.

5

ILLINOIS’ CURRENT DISSOLVED OXYGEN

GENERAL USE WATER QUALITY STANDARD

The Board’s responsibility in this rulemaking arises from the Act, which charges the

Board to “determine, define, and implement the environmental control standards applicable in

5

Please note that all filings with the Clerk of the Board must be served on the hearing officer and

on those persons on the Service List for this rulemaking. Before filing any document with the

Clerk, please confirm with the Clerk’s Office that you have the most recent version of the

Service List.

---

9

the state of Illinois.” 415 ILCS 5/5(b) (2006). Under Section 13 of the Act, the Board is granted

specific rulemaking authority to establish water quality standards.

See

415 ILCS 5/13 (2006).

Section 13(a)(1) of the Act specifically addresses dissolved oxygen:

(a)

The Board, pursuant to procedures prescribed in Title VII of this Act, may

adopt regulations to promote the purposes and provisions of this Title.

Without limiting the generality of this authority, such regulations may

among other things prescribe:

(1)

Water quality standards specifying among other things, the

maximum short-term and long-term concentrations of various

contaminants in the waters, the

minimum permissible

concentrations of dissolved oxygen

and other desirable matter in

the waters, and the temperature of such waters. 415 ILCS

5/13(a)(1) (2006) (emphasis added).

The Board adopted Illinois’ current General Use water quality standard for dissolved

oxygen in 1972, at which time the Board found it “essential to an adequate fish population.”

Effluent Criteria, Water Quality Standards, Water Quality Standards Revisions for Intrastate

Waters, R70-8, R71-14, R71-20, slip op. at 3 (Jan. 6, 1972). The standard is presently set forth

at 35 Ill. Adm. Code 302.206 and reads as follows:

Section 302.206

Dissolved Oxygen

Dissolved oxygen (STORET number 00300) shall not be less than 6.0 mg/l during

at least 16 hours of any 24 hour period, nor less than 5.0 mg/l at any time. 35 Ill.

Adm. Code 302.206.

Accordingly, the current standard permits dissolved oxygen to be less than 6.0 mg/L no

more than 8 hours in any 24-hour period, but at no time is dissolved oxygen allowed to fall

below 5.0 mg/L. Section 302.206 is set forth in Part 302’s Subpart B (“General Use Water

Quality Standards”), which “contains general use water quality standards which must be met in

waters of the State for which there is no specific designation (35 Ill. Adm. Code 303.201).” 35

Ill. Adm. Code 302.101(b);

see also

35 Ill. Adm Code 302.201. Generally, “all waters of the

State must meet the general use standards of Subpart B of Part 302,” except as otherwise

specifically provided in the Board’s regulations, such as for waters designated as secondary

contact and indigenous aquatic life waters.

See

35 Ill. Adm. Code 303.201, 303.204.

Richard Lanyon is the General Superintendent of the Metropolitan Water Reclamation

District of Greater Chicago (MWRDGC) and formerly the Director of Research and

Development for MWRDGC. He testified about the designated use class system for Illinois,

pointing out that the “general use” class applies to more than 99% of the river miles in the State.

Exh. 25 at 2. According to Lanyon, the “secondary contact and indigenous species aquatic life”

class in northeastern Illinois includes approximately 87 miles, while few are designated in the

“public water supply” class and none are designated in the “outstanding resource” class.

Id

.

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10

The purpose of the general use water quality standards is to:

protect the State’s water for aquatic life . . ., wildlife, agricultural use, secondary

contact use and most industrial uses and ensure the aesthetic quality of the State’s

aquatic environment. 35 Ill. Adm. Code 302.202.

IAWA asserts that the current DO standard is generally recognized to contain serious

flaws and is inconsistent with the current science. IAWA states that it undertook the effort of

updating the DO standard after conferring with IEPA because of the fundamental importance of

the DO standard as a water quality measure and its use as a component of various water

programs. PC 102 at 2.

Dr. James Garvey, an Associate Professor of Zoology and Associate Director of the

Fisheries and Illinois Aquaculture Center at Southern Illinois University,

6

was retained by

IAWA to evaluate Illinois’ current DO general use water quality standard. Exh. 35 at 1. Dr.

Garvey asserts that the current DO standard is unrealistic for most streams in the State because

oxygen concentrations fluctuate both seasonally and daily, often declining below the State

standards. According to Dr. Garvey, the current Illinois DO standard is “too simplistic for the

diverse waters of Illinois.”

Id

. at 1-2.

IAWA also notes that at the second hearing, Dr. David Thomas, Chief of the Illinois

Natural History Survey of DNR presented a letter he had prepared at the request of the

Lieutenant Governor’s Office. While Dr. Thomas expressed concerns regarding IAWA’s

proposal, he acknowledged that the current DO standard is too high for many water bodies

receiving discharges from wastewater treatment plants. PC 102 at 5; Tr.2 at 119.

Dennis Streicher represents IAWA and was the president of IAWA from 2004 to 2005.

Streicher states that IAWA members knew five years ago that the current Illinois DO standard

was incorrect. According to Streicher, they have worked with the existing rule and knew that it

was unattainable even in those Illinois waters that are among the least impacted by human

activities. Exh. 32 at 1-3.

DNR states that the existing DO water quality standard needs to be amended. PC 96 at 1.

According to DNR, the existing standard does not adequately account for the “varied [DO]

requirements of aquatic life” or for “how [DO] concentrations vary across a broad range of

natural aquatic conditions throughout Illinois.”

Id

., citing Exh. 23 at 1. IEPA echoes this

sentiment, adding that “all agree that the current standard for Illinois General Use waters is too

simplistic” and “needs to be revised.” PC 103 at 1, 16. According to IEPA, it is undisputed that

there are Illinois streams not meeting the current DO standard and that both the IAWA proposal

and DNR/IEPA proposal would “result in some significant (but smaller) number of

exceedances.”

Id

. at 14.

6

Dr. Garvey received a Ph.D in Zoology from Ohio State University, an M.S. in Zoology from

Ohio State University, and a B.A. in Zoology from Miami University, Ohio. Exh. 5 at 1.

---

11

Frevert, Manager of the Division of Water Pollution Control for IEPA, testified that he

believes the current dissolved oxygen standard is:

overly simplistic, outdated and not serving the state well. In that regard, I agree

with [IAWA’s] perspective. The comments of Dave Thomas on behalf of the

[DNR] focus on the variability of streams and their aquatic communities across

Illinois. This variability is even more pronounced as you consider lakes,

reservoirs, wetlands and other surface water bodies for which the dissolved

oxygen standard applies. Exh. 14 at 1-2;

see also

Tr.2 at 123-130; Exh. 13.

DNR believes that this rulemaking record contains the “data and science known today to

move forward with this significant improvement to the existing [DO] water quality standards.”

PC 96 at 13. DNR adds that the joint recommendations “will allow for targeting of limited state

resources to the most critical waters impacted by low [DO] concentrations.”

Id

. In the words of

Joel Cross, Acting Manager of the Watershed Protection Section within the Office of Resource

Conservation of DNR,

7

the joint-agency recommendations “significantly enhance protection for

aquatic life in comparison to the [DO] standard currently in place.” Tr.4 at 45.

IEPA similarly contends that the joint-agency proposal:

will adequately protect Illinois aquatic life while providing a more realistic and

useful standard; the recommended revisions will improve IEPA’s ability to focus

on those streams that are truly having or are most likely to have [DO] problems.

PC 103 at 2.

DNR does not view the joint-agency proposal as seeking a “lowering of [DO] standards within

some waters during certain times of the year, but rather as focusing needed protection for most

sensitive types and life stages of aquatic life where required.” Tr.4 at 46.

Environmental Law & Policy Center, Prairie Rivers Network, and Sierra Club state that

the current DO standard is “too simple” and produces both “false positives (i.e. it indicates DO

problems where DO levels are healthy) and false negatives (indicates that DO levels are healthy

where they are not).” PC 101 at 1. The Illinois Chapter of the American Fisheries Society states

that “there is general agreement that the existing standard is in need of revision.” PC 100 at 1.

The Illinois Farm Bureau points out that “[s]cience has advanced and the understanding

of natural systems and streams in Illinois has improved greatly since the standard was originally

set.” PC 2 at 2. According to the Illinois Farm Bureau:

7

Cross has been employed with DNR for seven and one-half years. He was previously

employed with IEPA for 19 years, the last nine of which he was Manager

of the Surface Water Section and the Planning Section in the Division of Water Pollution

Control. Cross holds a Bachelor’s degree in Zoology from Southern Illinois University at

Carbondale, Illinois. Tr.4 at 38-39.

---

12

The current, questionable standard wastes time, efforts, and money and does not

produce desired results. *** The flawed dissolved oxygen standard is not a

“stand alone” issue. Other programs are based on Illinois’ current outdated DO

standard. The dissolved oxygen standard is connected to the 303(d) List Water

Quality Impaired Streams and Lakes and therefore drives the development of total

maximum daily loads (TMDLs).

Many waters in Illinois are listed as impaired due to an existing dissolved oxygen

standard that is overly protective and does not reflect the needs of Illinois streams.

IEPA is developing TMDLs for streams on the 303(d) List. The process of

TMDL development is costly by itself, not to mention the millions of dollars

necessary for point and nonpoint sources to implement the plans to achieve load

reductions. It is therefore increasingly critical to ensure that the dissolved oxygen

standard used for the development of the 303(d) List is appropriate for Illinois

streams.

Id

. at 2-3.

In addition, Lanyon of MWRDGC testified that it is difficult to determine compliance

with the existing DO standard. Exh. 25 at 3, citing Tr.3 at 16. Enforcement of the standard

would require that multiple grab samples be taken over a period of at least eight hours.

According to Lanyon, 5.0 mg/L becomes a default standard applied for grab samples taken at

any time during the day. Exh. 25 at 3.

The Board recognizes that the DO general use water quality standard is central to many

regulatory programs, including the federal Clean Water Act’s Section 303(d) impairment

assessment and TMDL program. Further, the Board agrees that the State’s current DO standard

is outdated and needs to be amended consistent with USEPA’s 1986 National Criteria Document

or “NCD,” as adapted to Illinois waters. Given the wide array of aquatic life and conditions

across Illinois, the Board finds that the current DO standard is not sufficiently sophisticated. PC

96 at 1, citing Exh. 23 at 1; PC 101 at 1; PC 102 at 2, 5; PC 103 at 1, 16; Exh. 14 at 1; Exh. 32 at

1-3; Statement at 4-5. As Frevert of IEPA testified:

We’ve got a standard now that’s not helping us because we measure violations in

places where we believe the uses and particularly the aquatic community is

perfectly healthy and what it’s expected to be. *** [T]he standard can be overly

simplistic and it can’t apply everywhere if it’s actually going to help us manage

our resources and our functions properly. Tr.4 at 70-71.

The existing standard is so far out there and overly protective, it’s identifying on a

wholesale order streams that we need to focus on [such that] *** there are DO

flags going off all over the place. Tr.5 at 32;

see also

Tr.4 at 81, 83.

The Board further finds that this rulemaking record, as fully discussed below, is adequate

to proceed with a first-notice proposal that promises to significantly improve Illinois’ current DO

standard. PC 96 at 13; Statement at 1, 6.

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13

USEPA’S NATIONAL CRITERIA DOCUMENT

Both the IAWA proposal and the DNR/IEPA proposal are based on the current USEPA

National Criteria Document (NCD) for dissolved oxygen. Statement at 1; Exh. 23 at 2; Tr.4 at

32-33. The NCD, which was published in April 1986 and authored by Dr. Gary Chapman,

reviews the data on the effects of low levels of DO on the health, growth, and reproduction of

freshwater aquatic organisms. Data derived from fish studies were used to develop DO criteria

to protect freshwater aquatic organisms. The NCD presents the DO criteria in terms “coldwater”

and “warmwater” species, “life stages” of aquatic organisms, and duration of exposure to low

DO concentrations. Statement at 1; Exh. 2 (NCD) at 1-4.

In the NCD, USEPA recommends separate DO criteria for coldwater and warmwater

biota. While the coldwater criteria address the protection of salmonids, the warmwater criteria is

meant to protect nonsalmonids, which include many coldwater and “coolwater” fish, plus all

warmwater fish. Exh. 2 (NCD) at 2. In addition, the NCD provides for the establishment of

seasonal criteria based on the life stages of aquatic organisms present as long as data is available

to accurately determine the presence or absence of the more sensitive stages.

Id

. at 4. The early

life stages include embryonic and larval stages and all juvenile forms to 30-days after hatching.

Id.

at 34.

The DO criteria are derived from production impairment estimates, which are primarily

based on growth data and information on temperature, disease, and pollutant stresses. Exh. 2

(NCD) at 33. The NCD notes that the DO criteria values are set at 0.5 mg/L above the

concentrations that would be expected to result in slight production impairment. Therefore, the

DO criteria represent values between no production impairment and slight production

impairment. Accordingly, USEPA states, each criterion may be viewed as an “estimate of the

threshold concentration below which detrimental effects are expected.”

Id

.

USEPA’s criteria for coldwater fish apply to waters containing a population of one or

more species in the family of

Salmonidae

or to waters containing other coldwater or coolwater

fish determined to be more similar to salmonids in sensitivity than to most warmwater species.

Exh. 2 (NCD) at 33. USEPA notes in the NCD that some coolwater species may need to be

protected by the coldwater criteria where the warmwater criteria do not afford adequate

protection for such species. The warmwater criteria protect the early life stages of warmwater

fish as sensitive as channel catfish and other life stages of fish as sensitive as largemouth bass.

Id.

The NCD recommends a daily minimum to ensure that no acute mortality of sensitive

species occurs because of low DO concentrations. Exh. 2 (NCD) at 36. For early life stages, the

NCD recommends that the averaging period should not exceed 7 days to adequately protect the

most sensitive life stages of aquatic organisms. A 30-day average is recommended for other life

stages. The NCD also recommends the use of 7-day mean minimum value for other life stages to

prevent significant episodes of continuous or regularly recurring exposures to DO concentrations

at or near the lethal threshold.

Id.

---

14

The Board agrees with IAWA, DNR, and IEPA that USEPA’s 1986 NCD should serve as

“an important foundation” for updating Illinois’ DO water quality standard. PC 103 at 12;

see

also

Statement at 1; Exh. 23 at 2; Tr.4 at 32-33. The current Illinois standard for DO was

adopted in 1972, 14 years before the NCD was issued by USEPA. Exh. 23 at 7. Not

surprisingly then, as DNR and IEPA explain, the NCD’s criteria for DO address several elements

not addressed by Illinois’ current standard.

Id

. at 5. First, the NCD accounts for differences in

sensitivity to low DO among types of fish or macroinvertebrates.

Id

. Second, the State agencies

continue, the NCD accounts for differences in DO sensitivity depending on the life stages of fish.

Id

. Third, according to the agencies, the NCD “provide[s] practical considerations that account

for occasional natural occurrences of low [DO].”

Id

.

DNR and IEPA assert that adding these NCD elements would “greatly improve[] the

utility of the Illinois standards.” Exh. 23 at 7;

see also

Tr.4 at 46-47. The Board concurs and

now proceeds to address the respective proposals of IAWA and DNR/IEPA, both of which are

based on USEPA’s NCD.

INTRODUCTION TO THE IAWA PROPOSAL

IAWA is an organization of over 100 members and affiliate members, including

approximately 55 districts and municipalities. IAWA “support[s] administrators and managers

of wastewater collection and treatment agencies in the State of Illinois,” including publicly

owned treatment works (POTWs), water reclamation districts, and municipalities, as well as the

largest Illinois private wastewater treatment utility. IAWA Motion to Waive (April 19, 2004) at

1; Tr.1 at 13. IAWA’s rulemaking proposal seeks to amend Illinois’ current dissolved oxygen

general use water quality standards at 35 Ill. Adm. Code 302.206.

The IAWA proposal would replace the existing DO standard (6.0 mg/L during 16 hours

of any 24-hour period and an anytime minimum of 5.0 mg/L) with DO standards based on the

USEPA’s current National Criteria Document or NCD for dissolved oxygen. During the months

of July through February, IAWA proposes a daily minimum DO concentration of 3.5 mg/L and a

seven-day mean minimum of 4.0 mg/L. For the months of March through June, the IAWA

proposal sets forth a daily minimum of 5.0 mg/L DO and a seven-day mean of 6.0 mg/L DO.

Statement at 1-2, Exh. 1; PC 102 at 2. The IAWA maintains that its proposed standard is more

conservative than the NCD regarding DO minima. PC 109 at 3.

IAWA states that the DO standards it proposes for the months of March through June

address the early life stages of fish (egg, embryos, and larval stages) present in Illinois waters.

The DO standards proposed for the months of July through February afford protection during

other life stages, according to IAWA. Statement at 2. The IAWA states that in establishing the

months of late spawning and protecting early life stages, its proposed standard adheres to the

advice of local experts, as discussed below. PC 109 at 3.

IAWA describes March 1 through June 30 as the timeframe when early life stages of

sensitive species are present and freshwater has the capacity to hold high oxygen concentrations.

Further, according to IAWA, during warm, productive months and the remainder of the year

when species with sensitive early life stages have largely completed reproduction, its proposed

---

15

less stringent DO standards would apply. Exh. 16 at 2. Dr. Garvey emphasizes that IAWA

included running means to avoid chronically low DO concentrations. Dr. Garvey states that

IAWA’s proposed numeric DO values are consistent with, and with respect to the 3.5 mg/L

minimum value, more restrictive than, the 1986 USEPA NCD values.

Id.

at 3.

IAWA also asserts that the proposed seasonal DO standard structure is consistent with

the NCD. IAWA notes that its proposal, however, does not include a 30-day DO standard

recommended by the NCD. That is because, in IAWA’s estimation, compliance with the

applicable 7-day standard in most cases would ensure that the 30-day standard would also be

met. Statement at 2. When compared to the existing Illinois DO standard, IAWA states that its

proposed standard would require more extensive DO monitoring and may require the use of

continuous monitors.

Id

.

Because DO is essential to aquatic organisms for aerobic respiration, IAWA states that

regulatory agencies have established DO standards to ensure the maintenance of adequate DO in

waterways. IAWA notes that the current Illinois DO standard, adopted in 1972, does not reflect

the federal guidance and latest scientific data on DO. Statement at 4-5. The DO standard is

central to many other regulatory programs, such as the Total Maximum Daily Load or TMDL

and nutrient discharge control. IAWA therefore asserts that it is imperative that the DO standard

be valid and based on scientific data and verifiable evidence.

Id

. at 5. In light of this, IAWA

states that it decided to develop the necessary scientific information and propose a scientifically

defensible DO standard.

Id.

IAWA obtained the services of Dr. Garvey and Dr. Matt R. Whiles to conduct a

“literature survey and data review of the effect of dissolved oxygen levels on fish species in

Illinois.” Statement at 5. IAWA states that Drs. Garvey and Whiles, who are professors in the

Department of Zoology at Southern Illinois University, are recognized experts on fish species in

Illinois and the effect of water quality on those fish. IAWA notes that prior to undertaking the

assignment, Drs. Garvey and Whiles conferred with IEPA and DNR. Drs. Garvey and Whiles

reviewed the nature of Illinois water systems, which they state are dominated by warmwater

systems with exception of Lake Michigan.

Id.

at 6. They evaluated the effect of DO on

warmwater organisms, including fish and macroinvertebrate responses to oxygen stress, and

environmental variation in dissolved oxygen. Drs. Garvey and Whiles’ assessment also included

a review of literature on DO, including USEPA’s NCD for DO.

Id

.

Drs. Garvey and Whiles summarized their findings in a report entitled “

An Assessment of

National and Illinois Dissolved Oxygen Water Quality Criteria

” (April 2004) (“Assessment”).

The Assessment concludes that Illinois’ existing DO standard is overly restrictive and should be

modified based on published research concerning natural fluctuations in aquatic systems and

physiological tolerance of native aquatic life. Statement at 1. IAWA relies on the Assessment’s

conclusion to support its proposal. IAWA states that the proposal primarily affects wastewater

dischargers that discharge oxygen depleting substances, including biochemical oxygen demand

or “BOD” and nutrients. These dischargers include publicly owned treatment works or

“POTWs,” industrial dischargers, and agricultural point and nonpoint sources.

Id

. at 2.

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16

IAWA’s proposed amendments to Section 302.206 are set forth below, with proposed

additions underlined and proposed deletions stricken through:

Dissolved oxygen (STORET number 00300) shall

be determined on a monthly

basis as follows: not be less than 6.0 mg/L during at least 16 hours of any 24 hour

period, nor less than 5.0 mg/L at any time. 35 Ill. Adm. Code 302.206.

a.

During the months of July through February, dissolved oxygen shall not

be less than a one day minimum concentration of 3.5 mg/l, and a seven

day mean minimum of 4.0 mg/l. The mean minimum is defined as the

average of the minimum daily recorded dissolved oxygen concentrations

and should be based on a data recorder or representative grab samples.

b.

During the months of March through June, dissolved oxygen shall not be

less than a one-day minimum dissolved oxygen concentration of 5.0 mg/l,

and a seven day mean of 6.0 mg/l. The mean is defined as the average of

the daily average value and should be based on data collected by semi-

continuous data loggers or estimated from the representative daily maxima

and minima values. Statement, Att. 1.

MWRDGC states that IAWA’s proposed DO standard would establish a scientifically

sound and practical DO standard for aquatic life in Illinois. PC 98 at 1. The Chemical Industry

Council of Illinois (CICI) also supports IAWA’s proposal. PC 95 at 1. CICI states that IAWA’s

proposal would establish a seasonal DO standard that is “protective of the early life stages of

fish, aquatic insects and benthic organisms” and a minimum standard more stringent than that

suggested in USEPA’s NCD.

Id

. The Illinois Farm Bureau supports IAWA’s proposal as

“realistic and based on sound science.” PC 2 at 1. According to the Farm Bureau, because

“[i]mplementing standards is costly – both monetarily and time wise,” it is “far better to have

realistic standards that are achievable.”

Id

. at 2.

Later in the rulemaking, after submission of the joint DNR/IEPA proposal, discussed

below, IAWA asked that the Board adopt the 30-day average standard of 5.5 mg/L for other life

stages and the narrative standard, both proposed by DNR and IEPA. PC 102 at 1.

INTRODUCTION TO THE DNR/IEPA PROPOSAL

In response to IAWA’s proposal, DNR and IEPA also propose amendments to Section

302.206. The DNR/IEPA-proposed amendments to Section 302.206 share some aspects of the

IAWA’s suggested amendments, but also include substantial differences from those proposed by

IAWA.

DNR does not believe that IAWA’s proposed revisions to the DO water quality standard

are adequate. PC 96 at 1. It is DNR’s opinion that the IAWA proposal is inadequate because it

fails to: (1) protect species more sensitive to low DO than channel catfish and largemouth bass;

(2) provide adequate protection for early life stages; (3) address the range of waters contained in

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17

the general use category; and (4) adequately protect against long-term chronic effects of low DO.

Id

. at 2.

IEPA likewise states that IAWA’s proposal “fails to adequately protect some Illinois fish

and stream macroinverebrates that require minimum [DO] levels higher than the minima

represented by the IAWA-proposed standards.” PC 103 at 1-2. IEPA describes the NCD:

It recommends different standards for the protection of species that are most

sensitive to low [DO] (“coldwater[”]) vs . those that are less sensitive to low [DO]

(“warmwater[”]). Specifically, the NCD limits “warmwater” species to those

species that are equally or more tolerant of low [DO] levels as are largemouth

bass (as adults) or channel catfish (as early life stages). The record shows that

Illinois streams contain numerous fish species whose sensitivity to [DO] falls in

between the needs of the NCD “warmwater” fishes and those of the “coldwater”

salmonid species.

Id

. at 12-13, citing Tr.4 at 33-34, 97-98, Exh. 23 at 27-31.

According to IEPA, it and DNR developed a “technically sound and reasonable methodology to

address this failing in the IAWA proposal and adapted the NCD to Illinois in a scientifically

defensible manner.”

Id

. at 13, citing Tr.4 at 40-43, Exh. 23.

DNR describes the “primary supporting documentation” for the IAWA proposal

(Garvey/Whiles, April 2004

An Assessment of National and Illinois Dissolved Oxygen

Water Quality Criteria

, Exh. 1) as a “valid initial discussion” of the DO issue that nevertheless

“falls short of providing the complete and necessary protection for DO sensitive species in

Illinois, and species that are DO sensitive during early life stages.” PC 96 at 11.

According to DNR, the additional studies relied upon by IAWA (Csoboth thesis; Dr.

Davis’ research on physical characteristics; application of “Liebig’s law” for averaging

conditions; analysis of continuous DO concentration data) “are limited in scope and statewide

applicability,” in contrast to the biological data and scientific literature presented in support of

the DNR/IEPA joint recommendations. PC 96 at 11. DNR therefore urges the Board to use

“extreme caution” in applying the studies relied upon by IAWA “to support broad, statewide

conclusions for all waters applicable to these proposed amendments to the [DO] standard.”

Id

. at

12.

Given these DNR concerns with IAWA’s proposal, DNR:

became involved in this proceeding because State law provides that the

Department owns all aquatic life within our state boundaries and is responsible for

regulating and managing these natural resources. PC 96 at 2;

see also

Tr.4 at 40.

According to DNR, there clearly is a need to protect DO-sensitive species and species

that are DO-sensitive during early life stages, including the NCD required 30-day period for

larval development. PC 96 at 12. DNR explains that after the August 25, 2005 hearing, IEPA

and DNR jointly developed a set of recommendations to address the “shortcomings” of IAWA’s

proposal.

Id

. at 2.

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18

DNR and IEPA state that they used USEPA’s NCD as a “foundation from which to

interpret and incorporate more-recent information specifically applicable to the [DO] needs of

aquatic life in Illinois waters.” Exh. 23 at 2;

see also

Tr.4 at 33. DNR asserts that the joint

DNR/IEPA proposal makes “critical enhancements” to the IAWA proposal in four areas by

including:

1.

Two levels of numeric standards (instead of IAWA’s one level) to protect

identified DO-sensitive organisms in specified Illinois waters (“Level 1”

(enhanced protection) and “Level 2” (Exh. 23, Figure 1));

2.

An additional 30-day period needed to protect early life stages of fish (

i.e.

, March

through July rather than IAWA’s period of March through June);

3.

A narrative standard to protect waters that “naturally cannot achieve consistently

higher levels of [DO] such as wetlands, sloughs, river backwaters, and lakes and

reservoirs below the thermocline” (IAWA’s proposed DO standards would “apply

universally to all General Use waters” (Exh. 23 at 2, citing Exh. 1)); and

4.

30-day chronic DO standards (

i.e.

, daily mean averaged over 30 days), consistent

with USEPA’s NCD and absent from the IAWA proposal, that apply to both

levels of numeric standards for DO. PC 96 at 2;

see also

PC 103 at 2; Exh. 23 at

2-3, Figure 1; Tr.4 at 32-34, 46.

IEPA describes the first of the four above components as including both a “base

condition or a base dissolved oxygen standard patterned after the structure recommended in

USEPA’s [NCD] and generally protective of a full and diverse aquatic community” (Tr.4 at 24,

Frevert) and an incrementally “higher level that provides enhanced protection in waters that have

organisms especially sensitive to low [DO] levels” (PC 103 at 2). According to Cross of DNR:

A fundamental aspect of this position is that [DO] profiles naturally vary within

general use waters throughout Illinois; therefore a single uniform standard is not

appropriate given the available science today. Tr.4 at 40.

DNR maintains that the joint proposal’s narrative standard (item 3 above) and 30-day

chronic standards (item 4 above) “provide essential components to the [DO] standards necessary

for USEPA approval.” PC 96 at 13. Since the submittal of the joint DNR/IEPA proposal, DNR

notes, IAWA has generally accepted the joint-agency proposal’s narrative standard and the 30-

day chronic standards.

Id

. at 2. As noted, in PC 102 filed on December 20, 2006, IAWA asks

that the Board adopt a 30-day average standard of 5.5 mg/L for non-early life stages and the

narrative standard, both as proposed by DNR and IEPA. PC 102 at 1. According to DNR, the

remaining differences between IAWA and the State agencies consist of whether there should be

separate numeric standards to protect DO-sensitive organisms (item 1 above) and whether July

should be included among the months with more stringent standards to protect early life stages of

fish (item 2 above). PC 96 at 2;

see also

PC 103 at 2-3, n.1.

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19

DNR states that the joint-agency proposal is based on:

The only statewide dataset in this record (biological data for fish and

macroinvertebrates from 1,110 sampling sites),

The use of scientifically valid and sound processes for developing the joint

recommendations (described in detail within Exhibit #23),

Compilation of spawning periods for Illinois fish species representing nearly 100

years of data and information from six of the foremost authoritative texts on the

subject,

Expertise from field biologists in both Illinois EPA and Illinois DNR,

representing within IDNR alone, over 218 years of aquatic biology expertise in

Illinois,

Published scientific research from over 30 scientific literature sources contained

within the Technical Support Document, Exhibit #23. PC 96 at 12.

DNR maintains that the joint proposal with IEPA is “not unnecessarily over protective.” PC 96

at 10, quoting Tr.4 at 46-47. IEPA describes the joint-agency proposal as “scientifically sound

and defensible in light of the current available information on the [DO] needs of aquatic life in

Illinois.” PC 103 at 16.

Besides amendments to Section 302.206, the State agencies seek to add a new definition

to Section 302.100 and add a list of “Stream Segments for Enhanced Dissolved Oxygen

Protection” as Appendix D to Part 302. The proposed Appendix D is 37-pages long and

designates stream segments by basin name, segment name, segment number, end points by

latitude and longitude, and county. For example, the first two of the stream segments proposed

for enhanced DO protection appear as follows in Appendix D:

BASIN NAME

Segment Name

Segment No.

End Points

Latitude

Longitude

COUNTY

Illinois

Aux Sable Creek

239

start

41.3982125891033 -88.3307365155966

GRUNDY

end

41.5221610266554 -88.3153074461322

KENDALL

Baker Creek

123

start

41.0993159446094 -87.833779044559

KANKAKEE

end

41.1187483257075 -87.7916507082604

KANKAKEE

Exh. 21; PC 103 at 9.

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20

The proposal to have designated stream segments receive enhanced DO standards are further

discussed later in this opinion.

The amendments proposed by DNR and IEPA to Sections 302.100 and 302.206 are

provided here, with proposed additions underlined and proposed deletions stricken through:

302.100

Definitions

“thermocline” means the plane of maximum rate of decrease of temperature with

respect to depth in a thermally stratified body of water.

Section 302.206

Dissolved Oxygen

General use waters shall maintain dissolved oxygen concentrations at or above the

minimum values contained in subsections (a), (b) and (c) of this Section.

a.

General use waters at all locations shall maintain sufficient dissolved

oxygen concentrations to prevent offensive conditions as required in

Section 302.203 of this Part.

8

Quiescent and isolated sectors of General

Use waters including but not limited to wetlands, sloughs, backwaters and

below the thermocline in lakes and reservoirs shall be maintained at

sufficient dissolved oxygen concentrations to support their natural

ecological functions and resident aquatic communities.

b.

Except in those waters identified in Appendix D of this Part, the dissolved

oxygen concentration in the main body of all streams, in the water above

the thermocline of thermally stratified lakes and reservoirs, and in the

entire water column of unstratified lakes and reservoirs shall not be less

than the following:

1.

During the period of March through July,

A.

5.0 mg/l at any time; and

B.

6.0 mg/l as a daily mean averaged over 7 days.

2.

During the period of August through February,

A.

3.5 mg/l at any time;

B.

4.0 mg/l as a daily minimum averaged over 7 days and;

8

Section 302.203 reads in its entirety: “Waters of the State shall be free from sludge or bottom

deposits, floating debris, visible oil, odor, plant or algal growth, color or turbidity of other than

natural origin. The allowed mixing provisions of Section 302.102 shall not be used to comply

with the provisions of this Section.” 35 Ill. Adm. Code 302.203.

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21

C.

5.5 mg/l as a daily mean averaged over 30 days.

c.

The dissolved oxygen concentration in all sectors within the main body of

all streams identified in Appendix D of this Part shall not be less than:

1.

During the period of March through July,

A.

5.0 mg/l at any time; and

B.

6.25 mg/l as a daily mean averaged over 7 days.

2.

During the period of August through February,

A.

4.0 mg/l at any time;

B.

4.5 mg/l as a daily minimum averaged over 7 days; and

C.

6.0 mg/l as a daily mean averaged over 30 days.

d.

Assessing attainment of dissolved oxygen mean and minimum values.

1.

Daily mean is the arithmetic mean of dissolved oxygen values

measured in a single 24-hour calendar day.

2.

Daily minimum is the minimum dissolved oxygen value as

measured in a single 24-hour calendar day.

3.

The measurements of dissolved oxygen used to determine

attainment or lack of attainment with any of the dissolved oxygen

standards in this Section must assure daily minima and daily means

that represent the true daily minima and daily means.

4.

The dissolved oxygen value used in calculating or determining any

daily mean or daily minimum should not exceed the air-

equilibrated value.

Dissolved oxygen (STORET number 00300) shall not be less than 6 .0 during at

least 16 hours of any 24 hour period, nor less than 5.0 at any time. Exh. 20; PC

103 at 7-9.

The Environmental Law & Policy Center, Prairie Rivers Network, and Sierra Club

support the DNR/IEPA proposal, but suggest one modification to address concerns about oxygen

saturation levels. PC 101 at 1, 7, 11. The one modification suggested by these environmental

groups is to include a minimum DO level of 6.5 mg/L when water temperature is 10°C or below.

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22

To arrive at the 6.5 mg/ DO value, the environmental groups rely on the testimony of Dr.

Thomas Murphy, Professor

Emeritus

of Chemistry, DePaul University.

Id

. at 7, citing Tr.5 at 52.

For the Illinois Chapter of the American Fisheries Society, which “represents more than

250 fisheries and aquatic scientists within the state of Illinois,” it is the “overwhelming

consensus of the Chapter to fully support” the joint recommendations of DNR and IEPA. PC

100 at 1.

OVERVIEW OF RESPONSES TO THE DNR/IEPA PROPOSAL

IAWA states that the joint DNR/IEPA proposal differs from IAWA’s proposal in three

areas. First, the joint proposal extends the early life stage to July 31, rather than concluding on

June 30 as proposed by IAWA. Second, the joint proposal includes higher ambient DO levels

for proposed “enhanced” waters. Third, the joint proposal includes a narrative standard to

address offensive conditions and account for quiescent and isolated sections of general use

waters. PC 102 at 7-8. IAWA expresses serious concerns about “enhanced” waters and

extending the early life stage period to the end of July. As stated above, IAWA has amended its

proposal to include the 30-day average DO limit for other life stages, along with the narrative

standard.

Id

. at 15

IAWA argues that the proposed list of enhanced water segments is not based on any data

for DO, temperature, or habitat. PC 102 at 9. IAWA asserts that the proposed enhanced water

list includes a number of segments that are presently on the federal Clean Water Act Section

303(d) list as impaired for DO.

Id

. at 9. IAWA maintains that Dr. Garvey’s analysis of DO data,

including grab samples from 1993 through 2003 and semi-continuous data from 2004 and 2005,

shows that median DO concentrations in streams identified for enhanced protection decline

during June through August to a benchmark level below 5 mg/L.

Id

. at 11.

Regarding IEPA’s position that 2005 sampling data is not representative because of

severe drought, IAWA notes that the drought conditions actually provided a worst-case scenario

for assessing DO conditions in streams targeted for enhanced protection. Dr. Garvey’s analysis

shows that the IAWA’s proposed standard of 3.5 mg/L was rarely violated in the streams. PC

102 at 11-12. According to IAWA, the joint proposal for a two-tiered system is premature and

unwarranted by the data.

Id.

at 15-16.

IAWA asserts that its proposed 7-day minimum average of 4.0 mg/L, as it would apply in

July, yields more potential violations than the joint DNR/IEPA proposal’s 7-day minimum

average as it would apply in August, indicating IAWA’s standard’s greater sensitivity to low DO

conditions.

Id.

at 12.

Lanyon of MWRDGC recommends a standard identification, such as river miles, for

streams selected to have enhanced DO standards. Exh. 25 at 12; Tr.4 at 155. Lanyon also

cautioned that standards must be consistent for rivers shared with neighboring states. Exh. 25 at

12. In the Illinois River, Lanyon suggests there may be some enforcement ambiguity, pointing to

one segment proposed to meet the higher DO standards while the up and downstream segments

are not.

Id

. at 13.

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23

Dr. Garvey also reviewed a November 12, 2004 draft report generated by Edward Rankin

of the Center for Applied Bioassessment and Biocriteria in Ohio. Exh. 16, Att. 4. Dr. Garvey

testified that the Rankin report emerged during stakeholder deliberations as the result of input

from USEPA. According to Dr. Garvey, the Rankin survey shows a pronounced lack of

correlation between DO and biological integrity, as quantified for fish or macroinvertebrates.

However, at hearing, Dr. Garvey observed that the Rankin report does seem to indicate a weak

trend between DO and habitat quality in the studied system, but he stressed the difficulty in

assigning causality to DO as the major factor influencing the organisms in that particular system.

Tr.3 at 61-62. Based on the Rankin survey, Dr. Garvey asserts that warmwater streams

considered to be of high biological integrity in Ohio would violate the current Illinois DO

standard, but probably not IAWA’s proposed DO standard. Exh. 16 at 4.

Dr. Garvey expressed concern over the DNR/IEPA approach to selecting stream

segments for enhanced DO protection. Dr. Garvey states that the State agencies “recommended

an ‘enhanced oxygen’ tier for streams that contain fishes and invertebrates that were found by

Ohio Environmental Protection Agency to occur in Ohio waters with high average oxygen

concentrations.” Exh. 35 at 3. The selection of stream segments “based solely on associations

between aquatic organisms and average oxygen concentrations ignores other potential causal

factors such as habitat quality, gradient, and temperature,” according to Dr. Garvey.

Id

. Dr.

Garvey then concludes:

Thus, coining these organisms as “oxygen sensitive” and then using them to select

enhanced tier waters may be completely spurious. Only through experiments that

establish causality between oxygen tolerance and fish life processes can tolerance

be assessed. *** Recall, these investigators [Smale and Rabeni] used a

combination of lab assays and surveys to develop an index of oxygen sensitivity

in Missouri streams.

Id

. at 3-4.

It is Dr. Garvey’s view that “it appears that many of these streams, particularly the Fox

River, fail to provide adequate oxygen for aquatic life during part of the summer.” Exh. 35 at 10.

Dr Garvey continues: “This causes me to question the linkage between the aquatic assemblages

used to select the sites for enhanced status and oxygen needs of the resident organisms.”

Id

.

Considering the data on breeding periods for fish, Environmental Law & Policy Center,

Prairie Rivers Network, and Sierra Club support a standard that protects July spawning. PC 101

at 1, 3. These environmental groups point out that the argument made by IAWA for not

extending the standard through July is not supported by any economic data showing it would be

cheaper for dischargers.

Id

. at 4.

For low DO-sensitive species, Environmental Law & Policy Center, Prairie Rivers

Network, and Sierra Club agree with the DNR/IEPA assessment of the stream segment lines. PC

101 at 1, 5. These environmental groups state that although low DO conditions may be found at

a few sites in streams with DO-sensitive species, the whole water body should not be allowed to

fall to that DO level.

Id

. at 5. According to the environmental groups, the presence of DO-

sensitive fish in reaches with low DO for some period does not prove that the population is not

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24

already under stress and would not be affected if the entire segment were “hit” with low DO

levels constantly or in combination with other stressors.

Id

. at 6.

The Illinois Chapter of the American Fisheries Society states that the IAWA proposal

would “inadequately protect aquatic life throughout the range of aquatic habitats and

environmental conditions present in Illinois.” PC 100 at 1. The Illinois Chapter maintains that

the DNR/IEPA proposal, in contrast, follows NCD protocol:

for safeguarding organisms known to be sensitive to dissolved oxygen as well as

early life stages (eggs, embryos, larvae) of

all

fish and aquatic invertebrates.

Id

.

(emphasis in original).

According to the Illinois Chapter of the American Fisheries Society, only the DNR/IEPA

proposal “recognizes the state’s vast biological diversity and the resultant need to stratify water

quality protection standards with regard to space and time.”

Id

. at 2. The Illinois Chapter “fully

supports the approach, methodology and resulting recommendations crafted by the two agencies

with statutory responsibility for the protection of Illinois’ fisheries and aquatic resources” and

urges the Board to adopt the DNR/IEPA proposal.

Id

.

IAWA PROPOSAL

An Assessment of National and Illinois Dissolved Oxygen Water Quality Criteria

(Garvey-Whiles, April 2004)

In support of its proposal to revise Illinois’ current DO standard, IAWA submitted a report

entitled “

An Assessment of National and Illinois Dissolved Oxygen Water Quality Criteria

”

(Garvey-Whiles, April 2004) (“Assessment” or “Garvey-Whiles report”). The Assessment,

which was prepared by Drs. Garvey and Whiles, includes a review of current literature on DO in

natural systems and potential effects of hypoxia (low DO) on aquatic life, and an evaluation of

the current Illinois DO standard and the national criteria. Further, the Assessment sets forth

recommendations for reevaluating and modifying the current Illinois DO standard based on

published research concerning natural fluctuations in aquatic systems and physiological

tolerances of native aquatic life. Exh.1 at 6. The Assessment is summarized below.

Importance of DO in Freshwater Habitats

The Assessment notes that DO is a critical resource in fresh water because: DO is

essential to aquatic organisms for aerobic respiration; it is less abundant in aquatic habitats due

to its low solubility; and DO availability to aquatic organisms is influenced by a number of biotic

and abiotic factors, such as metabolic processes, temperature, salinity, atmospheric and water

pressure, and diffusion. Exh. 1 at 6. The levels of DO in freshwater habitats are affected by

natural and anthropogenic activities. Particularly, activities resulting in discharges of nutrients

and sediments, and thermal discharges lead to reduced oxygen concentrations. As such,

regulatory agencies focus on DO levels in setting standards and monitoring requirements, since

DO is a critical limiting resource in freshwater habitats and DO levels are influenced by human

activities.

Id.

at 7-8. While there is general agreement that DO levels are an important

component of water quality standards, the Assessment contends that there is less consensus when

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25

establishing standards for a given region and habitat or determining violations of the standards.

Id.

at 8.

Warmwater Organisms

The Assessment states that with the exception of certain species such as smallmouth bass,

fish in warmwater systems are tolerant of temporary periods of low DO. Exh. 1 at 9, citing

Chapman 1986 (NCD), Smale and Rabeni 1995a. However, some macroinvertebrates, such as

burrowing mayflies and freshwater mussels are far less tolerant of prolonged exposure to

hypoxic conditions than most fish.

Id.

at 9-10, citing Li-Yen 1998, Chapman 1986 (NCD),

Winter

et al

. 1996, Corkum

et al

. 1997. The Assessment maintains that many

physiological

responses within the aquatic organisms occur to ensure survival under hypoxic conditions.

These responses include increased ventilation to increase oxygen transfer across the respiratory

surface, reduction of activity and metabolism, and reliance on anaerobic glycolysis.

Id.

at 11,

citing Beamish 1964, Fernandes

et al

. 1995, MacCormick

et al

. 2003, Crocker and Cech 1997,

Hagerman 1998, Childress and Siebel 1998, and Wu 2002.

The Garvey-Whiles report also notes that aquatic organisms have

behavioral

responses to

hypoxic conditions. Organisms move from areas of low DO levels to areas with higher DO

concentrations. Some stream fish and amphipods move towards the air-water interface during

low DO conditions. Exh. 1 at 12, citing Henry and Danielopol 1998. Additionally, the

Assessment states that early life stages of aquatic organisms are the most sensitive to hypoxic

conditions.

Id.

, citing Chapman 1986 (NCD). The ability to tolerate hypoxia improves in

aquatic organisms only upon formation of oxygen regulating structures such as gills and

associated respiratory behavior.

Id.

, citing Jobling 1995. Aquatic species also adapt to cope

with low DO conditions in nesting areas, according to the Assessment. These adaptations

include nest fanning, and semibuoyant eggs or adhesive eggs that attach to vegetation.

Id.

at 13,

citing Hale

et al

. 2003, Corbett and Powles 1986.

The Assessment maintains that the manner by which these adaptations allow aquatic

species to “cope with natural cycles and spatial heterogeneity of dissolved oxygen must be

considered when developing specific criteria.” Exh. 1 at 13. Further, according to the

Assessment:

Because most species in Illinois spawn in spring when flow rates are high and

temperature-induced hypoxia is low, seasonal fluctuations in dissolved oxygen

must also be factored into the evaluation of dissolved oxygen criteria for Illinois.

Id

.

Aquatic Organisms Responses To Oxygen Stress

The Assessment states that a review of studies pertaining to warmwater fish species in

Illinois indicates that adults and juveniles of most species survive DO levels that occasionally

decline below 3 mg/L. Exh. 1 at 13, citing Chapman 1986 (NCD). The Assessment notes that

the critical DO concentration, which is defined as the oxygen concentration at which ventilation

ceases, for 35 fish species that inhabit small warmwater streams ranged from 0.49 mg/L to 1.5

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26

mg/L.

Id.

, citing Smale and Rabeni 1995a. Based on this critical DO concentration range, the

Garvey-Whiles report contends that the 1-day minimum of 3.0 mg/L DO recommended by the

NCD for adult life stage warmwater fish is sufficiently protective of stream fish assemblages.

Id.

at 15.

The Assessment notes that during early life stages, tolerance of short-term exposure to

hypoxia declined from embryonic to larval stages. Exh. 1 at 15, citing Peterka and Kent 1976.

Many fish become free swimming upon transforming to larvae, and thus may not require high

tolerance to low DO conditions in benthic spawning areas. However, species with benthic larvae

would still be sensitive to chronic low DO levels, according to the Assessment. A non-linear

regression analysis performed by Drs. Garvey and Whiles using Dr. Chapman’s data (Chapman

1986 (NCD)) found the DO concentration at which 50% survival occurred (similar to LC50

value) for tolerant species to be 2.8 mg/L, and for intolerant species to be 4.3 mg/L.

Id.

at 16. A

second analysis, done by using the two-dimensional Kolmogorov-Smirnov test, resulted in

threshold DO concentrations of 3.72 mg/L and 3.75 mg/L for tolerant and intolerant species,

respectively. Based on these analyses, the Assessment states that a conservative interpretation

would be that survival of intolerant embryos and larvae begin to decline below 4.3 mg/L, and

similar effects occur for tolerant species below 3.7 mg/L.

Id.

According to the Assessment, low DO levels can reduce growth by reducing foraging

behavior and increasing metabolic costs. Exh. 1 at 17. A number of studies have shown

significant decline in growth at lower DO levels.

Id.

at 17, citing JRB Associates 1984. The

Assessment notes, however, that extrapolating growth results from laboratory studies to the field

is problematic because of differences in food availability.

Id.

, citing Chapman 1986 (NCD).

The Assessment further notes that while there is not much information on the effect of low DO

levels on reproductive viability, hypoxia has been shown to be an endocrine disruptor affecting

fish reproductive success.

Id.

at 18, citing Wu

et al

. 2003. The Assessment states that a majority

of Illinois warmwater fish species spawn between spring and early summer (March through

June). The Garvey-Whiles report maintains that this time period, which corresponds to higher

DO levels in streams and lakes, allows young fish to overlap with a spring pulse in primary

production, and provides adequate time for fish to become large and survive the winter.

Id.

at

19, citing Garvey

et al

. 1998b. The Assessment states that a few species that continue to spawn

through the summer must have adaptations to reproduce successfully.

Id

.

Regarding macroinvertebrates, the Assessment asserts that the communities and

assemblages in habitats with low DO levels are dominated by taxa that breathe atmospheric

oxygen through respiratory tubes or the use of transportable air stores. Exh. 1 at 19. Taxa

associated with highly oxygenated environments use tracheal gills for respiration. They are

usually underrepresented or absent in habitats with low DO, according to the Assessment. The

distribution patterns of macroinvertebrates have been the basis for numerous macroinvertebrate-

based biomonitoring programs because they are fairly consistent and good indicators of

increasing organic pollution and associated low DO levels.

Id.

at 20, citing Hilsenhoff 1987,

Hilsenoff 1988, Lenat 1993, Barbour

et al

. 1999.

According to the Garvey-Whiles report, because of the great diversity of freshwater

invertebrates, there is not much information about their oxygen requirements and tolerances. A

---

27

number of studies dealing with lethal effects for many taxa indicate a range of lethal DO minima

from less than 0.6 mg/L for the midge

Tanytarsus

to 5.2 mg/L for an ephemerellid mayfly, and a

DO96-hou LC-50 concentration between 3 to 4 mg/L for about half the insects studied. Exh. 1 at

20, citing Chapman 1986 (NCD). The assessment also notes that freshwater mussels exhibit a

widespread range of tolerances to hypoxia. In addition to lethal effects, low DO levels result in

reduced growth rates in macroinvetebrates because of decreased aerobic respiration rates and the

use of energy reserves.

Id.

at 21, citing Fox and Sidney 1953, Erikson

et al

. 1996.

Dissolved Oxygen Variation in Natural Systems

The Assessment asserts that DO concentrations fluctuate even in pristine natural systems,

causing organisms to move or tolerate occasional occurrence of hypoxia. Exh. 1 at 22. While

most species have some adaptations to allow them to tolerate occasional low DO, others are

specifically adapted to survive in areas of chronically low DO.

Id.

at 22, citing Hamburger

et al

.

2000, MacNeil

et al

. 2001.

The Assessment states that the typical occurrence of hypoxia in natural systems happens

in stratified lakes during the summer when the lower strata of lakes become depleted of oxygen.

Research has confirmed, continues the Assessment, that hypoxia in stratified lakes severely

restricts habitat for fish and other organisms.

Id.

at 23, citing Nurenberg 1995a, Nurenbergb,

2002. The Assessment notes that suboptimal temperatures and low DO during summer months

may cause “summer kills” of fish that have poor tolerance to hypoxia. Also, “winterkills” may

occur under snow covered ice in lakes because of oxygen depletion caused by natural

biologically processes.

Id.

The Assessment states the while some studies have tried to link the oxygen-driven

distribution of organisms in the field with laboratory-derived critical minima, there is no current

published literature that explicitly links the distribution of organisms to the warmwater criteria

recommended by the NCD or the Illinois standard. Exh. 1 at 25. A study used a laboratory-

derived oxygen minima to generate a hypoxia tolerance index for a number of headwater streams

and found that the hypoxia tolerance index had a strong correlation with the mean DO

concentration.

Id.

at 25-26, citing Rabeni

et al

. 1995a and 1995b. This research provides a

framework for characterizing streams by fish response to expected oxygen minima.

Id.

at 26.

The Assessment notes that while the mechanisms underlying DO fluctuations have been

understood, there is a need to document the spatial extent, duration, frequency, and magnitude of

DO fluctuations.

Id

. at 26.

National and Illinois DO Standards

The Garvey-Whiles report states that USEPA’s NCD recommends criteria based on a

two-concentration structure, with both a mean and a minimum for both coldwater and

warmwater systems. Exh. 1 at 8, citing Chapman 1986 (NCD). The criteria, which are further

divided into early life stages and other life stages, reflect DO levels that are 0.5 mg/L above the

levels that would cause impairment. Therefore, each criterion value is the threshold below which

there may be some impairment.

Id.

at 27. The NCD recommends average levels over a period

of seven days for early life stages of fish, when they are very sensitive to oxygen stress. A

---

28

longer averaging period of 30 days is recommended for other life stages.

Id.

at 28. The daily

minimum values are recommended to protect against acute stress or mortality of sensitive

species.

Id.

The NCD also addresses unique problems posed by point source discharges in

which DO concentrations can be manipulated.

Id

. at 29.

The Assessment notes that the Illinois DO standard was adopted in the 1970’s. This

standard, which is based on a simple minimum allowable concentration, does not address natural

cycling of DO and it is not supported by recent scientific data on responses of aquatic life to

hypoxic conditions, according to the Garvey-Whiles report. Exh. 1 at 9. The current Illinois

standard does not differentiate between coldwater and warmwater organisms and is based on a

single minimum, “rather than acknowledging that fluctuations may occur, necessitating inclusion

of an average.”

Id.

at 30.

Illinois Waters

The Garvey-Whiles report notes that most inland waters in Illinois are dominated by

warmwater, non-salmonid faunal assemblages. While a formal definition of “warmwater

systems” is still lacking, the Assessment defines warmwater systems as those that are typically

diverse, centrarchid-dominated, and common in the midwestern and southern United States.

Exh. 1 at 9, citing Magnuson

et al

. 1979b. The Assessment states that Illinois waters are

designated by IEPA under several use categories, including aquatic life, primary contact,

secondary contact, public water supply, fish consumption, and indigenous aquatic life.

Id.

at 31,

citing IEPA 2002.

The Assessment focuses on the applicability of the DO standard for the State’s aquatic

life use category, which is “intended to provide full support for aquatic organisms.” Exh. 1 at

31. The Assessment maintains that Illinois uses a valid approach to determine whether a

waterbody meets the aquatic life designation. This approach, continues the Assessment, relies on

the relevant biotic indicator, such as the Index of Biotic Integrity (IBI) for fish or the

Macroinvertebrate Biotic Index (MBI), to assess the overall effects of water and habitat quality,

and identifies impairments based on compliance with DO standards. Exh. 1 at 31-32, citing Karr

1981, Karr

et al

. 1986, Bertrand

et al

. 1996, IEPA 1994. The Assessment notes that while

current IEPA methods for assessing health and impairment are adequate, the Illinois DO

standards need to be refined. Specifically, the Assessment asserts that the current DO standards

based on daily minima are too conservative and should be modified to reflect actual local

conditions.

Id

at 35.

Garvey-Whiles Recommendations

The Garvey-Whiles report recommends that the Board adopt the NCD warmwater criteria

with some modifications. During early life stages, the Assessment recommends a daily

minimum DO level of 5.0 mg/L and a 7-day mean of 6.0 mg/L. The Assessment suggests March

1 through June 30 as the time period for the early life stages. Exh. 1 at 36. For the other life

stages (

i.e.

, July 1 through February 28 or 29), the Assessment recommends a daily minimum

DO level of 3.5 mg/L and a 7-day mean minimum of 4.0 mg/L. The Assessment asserts that its

daily minimum DO level of 3.5 mg/L, which is higher than the 3.0 mg/L level recommended for

---

29

other life stages by the NCD, is based on reevaluating the NCD to account for the adult life

stages and spawning times for common warmwater fish taxa in Illinois.

Id.

at 37.

Dr. Garvey later testified further about the proposed two-season DO standard. During

March through June, “when the majority of early life stages of many fishes and other aquatic

organisms are produced,” he recommends a DO concentration that provides “sufficient oxygen

to support the metabolic needs of eggs and larvae.” Exh. 35 at 2. During this time of year,

according to Dr. Garvey, “streams are typically flowing, primary productivity is accelerating but

not peaking, and temperatures are cool to moderate.”

Id

. Therefore, Dr. Garvey continued, high

DO concentrations are expected to be available to young aquatic organisms. Dr. Garvey further

states that “[t]he literature and growing state-wide oxygen data set demonstrate that, for warm-

water, low-gradient systems common in Illinois, concentrations should not decline below 5 mg/L

and weekly averages should not decline below 6 mg/L.”

Id

.

Another deviation from the NCD is the Assessment’s exclusion of a 30-day mean DO

criterion for other life stages. The Assessment maintains that a shorter window of time, ranging

from 1-7 days, better captures responses of all life stages to changes in the DO level, and is more

“biologically relevant.” Exh. 1 at 35. Dr. Garvey later commented on the non-spring, 30-day

mean of 5.5 mg/L advocated by NCD. According to Dr. Garvey, applying the 30-day mean

generated many (23%) violations in a high-quality Illinois stream, Lusk Creek, and adding this

standard may generate unmerited violations. Exh. 16 at 4. He says that the biological relevance

of the 30-day mean DO standard remains unclear.

Id.

at 7. Dr. Garvey ultimately recommends a

30-day running average of 5.5 mg/L DO as recommended in the NCD, even though it has “little

biological support” in his view. Exh. 35 at 2.

In addition to recommending the DO criteria described above, the Assessment includes

recommendations on DO monitoring. In the case of manipulatable discharges, measurements

should be taken at the zone of mixing and at an area beyond the direct influence of mixing,

according to the assessment. Exh. 1 at 38. When diel fluctuations are extreme, the Assessment

notes that monitoring should focus on daily minima. Further, detecting violations of daily

minima using infrequent spot checks may be a better indicator of larger problems than those

measured with a continuous data logger.

Id.

The Assessment recommends that DO

measurements be taken in pool or run habitats in the water column. DO measurements should

not be taken in riffles or at sediment/water interface, according to the Assessment.

Id.

at 39.

The Assessment clarifies that its recommendations are meant for only warmwater

systems in Illinois and should not be applied to Lake Michigan, which is a large-scale, native

coldwater fisheries system. The recommendations are also not appropriate for wetlands. Exh. 1

at 39-40. The Assessment states that there is a need for additional research on the specific

relationship between biotic integrity, DO, and other water quality and habitat factors. Any

research data that establishes relationships between biotic integrity and DO levels in Illinois

streams will allow for the development of physiologically based hypoxic indices, which may be

helpful in the monitoring and assessment of surface water habitats in Illinois.

Id.

at 41.

---

30

Dr. Garvey’s Analysis of USGS and IEPA DO Data

From Eight Illinois Streams (2001-2003)

Dr. Garvey testified that he applied Illinois’ current DO standard and IAWA’s proposed

DO standard to eight Illinois streams for which extensive DO and temperature monitoring data

were collected by the United States Geologic Survey (USGS) and IEPA. Exh. 9 at 2. His

analysis is summarized in the report entitled “

Long Term Dynamics of Oxygen and Temperature

in Illinois Streams

” (Garvey 2004), which is discussed in detail below.

See id

., Att. 1. Dr.

Garvey notes that his report was reviewed by USGS and IEPA staff, as well as by Dr. Whiles of

Southern Illinois University, and reflects the comments of reviewers.

Id.

Dr. Garvey asserts that the USGS-IEPA “long-term data are unprecedented” and that he

is not aware of any similarly comprehensive dataset for streams of the Midwestern United States.

Exh. 9 at 2-3. USGS and IEPA collected semi-continuous DO and temperature data for eight

stream reaches during the late summer of 2001 through the fall of 2003.

Id.

at 3. The monitored

stream reaches were the North Fork Vermillion River near Bismarck, the Middle Fork

Vermillion River near Oakwood, the Vermillion River near Danville, Lusk Creek near Edyville,

the Mazon River near Coal City, Rayse Creek near Waltonville, Salt Creek near Western

Springs, and the Illinois River near Valley City. Dr. Garvey notes that the stream segments

varied widely in physical characteristics, surrounding land use and latitude, and five of the

stream segments are currently on the most recent federal Clean Water Act Section 303(d)

impaired list.

Id

.

Dr. Garvey contends that the results of the analysis uphold the conclusion of the Garvey-

Whiles report. He states that the DO levels in all eight streams violated Illinois’ current DO

standard. The frequency with which violations occurred ranged from 1% of the days to 65% of

the days. Exh. 9 at 3. The violations occurred in unimpaired, unlisted stream segments, as well

as in impaired Section 303(d)-listed stream segments. Dr. Garvey notes that it is generally

expected that nutrient enrichment is the primary factor affecting dissolved oxygen dynamics.

The monitoring data for Salt Creek, however, indicate that other factors such as stream physical

habitat may also affect DO dynamics.

Id.

at 4.

Applying IAWA’s proposed DO standard, Dr. Garvey states that the number of violations

in unimpaired streams, such as Lusk Creek, is greatly reduced, while still capturing violations in

impaired streams. Exh. 9 at 4. Dr. Garvey notes that the Lusk Creek segment, which is in the

Lusk Creek Wilderness area of the Shawnee National Forest, is considered pristine with a highly

regarded, intact, and diverse fish and macroinvertebrate assemblage. According to Dr. Garvey,

the application of IAWA’s proposed DO standard to the monitoring data resulted in an increase

in the frequency of violations in two of the severely oxygen-impaired streams and indicated the

time period when DO problems occur.

Id.

Dr. Garvey states that the temperature data for Lusk Creek indicate that DO

concentrations were lowest at intermediate summer temperatures and that there were no

substantive differences in temperatures among streams across the north-south gradient of the

State. Exh. 9 at 5. This, according to Dr. Garvey, suggests that it is not the seasonal maximum

stream temperatures that reduce DO concentrations. He contends that the temperature data show

---

31

that IAWA’s proposed DO standard effectively captures oxygen dynamics occurring in natural,

fully-functioning Illinois streams, such as Lusk Creek.

Id

.

Dr. Garvey also notes that habitat modification is a significant factor affecting resident

species assemblages. Specifically, in pooled areas of streams where the frequency of violations

of Illinois current DO standard is higher than in open reaches, Dr. Garvey argues that altering or

degrading species composition results from changes in river habitat and oxygen dynamics, more

so than just low DO concentrations. Exh. 9 at 6. He further states that the data for the eight

monitored streams show no relationship between biotic integrity scores and oxygen minima as

estimated by frequency of violations of either the current or IAWA-proposed standards.

Id.

The

biotic integrity scores are more aligned with habitat quality factors such as stream’s substrate,

habitat diversity, and riparian vegetation, suggesting that habitat quality rather than DO primarily

influences species composition.

Id

.

Finally, Dr. Garvey addressed the issue of early life stages, which IAWA proposes for

March through June, as compared to the early life stages time period under Illinois’ current

ammonia standards, which extends through October. Dr. Garvey maintains that the proposed

early life stage time period is appropriate for DO because the dynamics of DO and total ammonia

differ in streams. Exh. 9 at 7. The total ammonia concentrations depend on discharge and do not

vary on a seasonal basis, according to Dr. Garvey. Further, the toxicity of total ammonia

increases with increasing temperature, requiring the application of the more stringent standard

for a longer time period. Dr. Garvey also notes that according to Dr. Chapman, author of

USEPA’s NCD for DO, the timing of seasonal standards should be based on the experts’

working knowledge of the fish community in the particular state.

Id.

at 7-8.

In sum, Dr. Garvey asserts that results of the eight-stream monitoring data analysis

confirm the findings of the Garvey-Whiles report. He states that IAWA’s proposed DO

standards may be applied statewide. Dr. Garvey recommends, however, that regional standards

or stream classifications be established eventually, giving consideration to biotic integrity,

habitat quality, and water quality goals. Exh. 9 at 9.

Long Term Dynamics of Oxygen and Temperature In Illinois Streams

(Garvey 2004)

As stated above, the Garvey report (2004) details the evaluation of how Illinois’ current

and IAWA’s proposed DO standards characterize streams in the State relative to season, stream

quality, and geographic location. Exh. 9, Att. 1 at 3. Dr. Garvey analyzed water quality

monitoring data for DO and temperature collected by USGS and IEPA in eight stream segments

over a two-year period, as noted above.

Id

. IEPA and USGS measured temperature and DO at

each stream site every 30 minutes during the late summer of 2001 through the fall of 2003.

Using this data, the daily averages and daily minima were calculated for each stream by Dr.

Garvey. For Illinois’ current DO standard, a violation was determined by calculating the hours

that the DO concentration was less than 5 mg/L. Similarly, for IAWA’s proposed DO standard,

daily minima, 7-day mean, and 7-day mean minima were calculated for each stream. The seven-

day averages were determined as running averages across 7 days.

Id

. at 6-7. The characteristics

of the monitored river segments are summarized in the table below.

Id.

at 3-6.

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32

Characteristics of Eight Monitored Stream Segments (Garvey 2004)

River

Segment

Location

Substrate Width

x

Depth

(m) at

Logger

Stream

Surface

Area

(km

2

)

Drainage

Area

Annual

Mean

Stream

Flow

(m

3

/s)

303(d)

Listed

North

Fork

Vermillion

East-Central

Ill.

Gravel

riffle with

vegetation

20 x

0.3-1.0

1.14

Agricultural 8.8

Yes -

pathogens

Middle

Fork

vermillion

East-Central

Ill.

Gravel

riffle with

vegetation

30 x 1

5.4

Agricultural 11.4

No

Vermillion

East-Central

Ill.

Gravel

and sand

50 x 2-

3

24.3

Agricultural 28.9

No

Lusk

Creek

Southeastern

Ill.

Sand,

gravel

cobble

and

bedrock

10 x 2

0.22

Forested

(76%),

Agricultural

1.7

No

Mazon

River

North-

Central Ill.

Rock and

gravel

riffle with

vegetation

in channel

50 x

17

Agricultural

(94%),

Urban (4%)

9.9

Yes –

PCBs and

pathogens

Rayse

Creek

Southern Ill. Not

provided

6 x >1

0.62

Agricultural,

Forested

(17%)

2.5

Yes –

nutrients,

low pH,

enrichment,

pathogens,

and

suspended

solids

Salt Creek

Northern

Partial

riffle,

heavy

summer

aquatic

growth

23 x

7

Urban

3.8

Yes –

nutrients,

salinity,

and

pathogens

Illinois

River

East-central

Not

provided

200 x 8 1003

Forested

(50%)

Urban

(50%)

643.5

Yes –

metal and

PCBs

Exh. 9, Att. 1 at 3-6.

---

33

The results indicate that DO levels declined below the current Illinois standard in all

stream segments during the summer, with the frequency of violations ranging from 2% to 65% of

the days during the two-year monitoring period. The DO pattern did not indicate any correlation

with latitude, stream quality, or stream size, according to Dr. Garvey. Exh. 9, Att. 1 at 7.

Regarding temperature, the differences in monthly averages among all streams were less than

4

o

C during the summer. Dr. Garvey states that although temperature differences were more

pronounced during the winter, oxygen stress is not as important during the winter.

Id

.

The Garvey report notes that the DO data for Lusk Creek, which is a forested and

functioning stream, had a higher frequency of violations of the current DO standard than two of

the impaired streams. This suggests to Dr. Garvey that the frequency of violations is not

associated with stream impairment. Exh. 9, Att. 1 at 11. However, the application of the

proposed IAWA standard to Lusk Creek data significantly reduced the frequency of DO

violations. The proposed IAWA standard also increased the frequency of violations in Rayse

Creek, which is an impaired stream.

Id.

This, maintains the Garvey report, suggests that land

use, flow, and alteration of the watershed likely are major factors influencing oxygen dynamics

in streams. Further, temperature and DO were negatively related in all streams.

Id.

at 10.

However, in Lusk Creek, the lowest DO levels occurred at intermediate temperature. Based on

DO-temperature data for Lusk Creek, the Garvey report contends that linkage between oxygen

stress and high temperature stress for resident species appears to be relatively unimportant.

Id.

at

13.

The Garvey report maintains that rather than “linking temperature and oxygen,

understanding the relationship between flow and oxygen will likely be more informative for

predicting effects on resident organisms.” Exh. 9, Att. 1 at 11. The report notes that DO levels

are typically lower in pooled portions of streams.

Id.

at 13, citing Santucci and Gephard 2003,

Hammer and Linke 2003. According to Garvey, species with adaptations to increased siltation,

reduced flow, and increased open water are abundant in pooled areas, but flow-dwelling species

are rare or absent. The Garvey report asserts that shifts in the community are likely caused by

altered habitat rather than low DO levels.

Id.

at 13. According to the report, however, if

IAWA’s proposed standards are not met in the pooled areas of a stream, few organisms will

persist regardless of habitat adaptations.

Id

. at 14.

Dr. Garvey later reiterated in testimony that the primary factor affecting biological

integrity in streams is the physical template, and that the best method for monitoring integrity is

through the assessment of the resident organisms. Dr. Garvey finds that oxygen typically

occurring in natural streams explains very little of the variation in biological integrity. In his

view, the goal of resource agencies should be to maintain oxygen concentrations above IAWA’s

proposed seasonal minima and focus their resources on improving the likely culprit affecting

variance in integrity among warmwater streams: physical habitat. Exh. 16 at 8.

The Garvey report concludes, on the basis of the most comprehensive, long-term DO and

temperature dataset available for Illinois, that IAWA’s proposed standards:

better capture oxygen violations in truly impaired streams (i.e., those with

modified biota such as Rayse Creek) relative to fully functioning streams such as

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34

Lusk Creek with high quality habitat and a diverse aquatic biotic assemblage. If

the frequent violations of the Illinois standard were biologically meaningful, then

Lusk Creek would have a greatly reduced or modified assemblage and would be

listed as impaired. This is not the case and the frequent declines in [DO]

concentration approaching the proposed summer minimum within the pools of

this system during summer do not compromise spawning fishes or other

organisms. Exh. 9, Att. 1 at 14.

The report maintains that the species reproducing during the summer have adaptations for natural

fluctuations in oxygen during the warmer season. Further, according to Dr. Garvey, alterations

to habitat quality and stream flow significantly affect the composition of stream communities.

Id.

at 15.

Dr. Garvey testified that the data for the eight continuously monitored streams were

subsequently refined, summarized, and published in a 2005 USGS report. Exh. 16, Att. 2. Dr.

Garvey claims that analysis of these data by Paul Terrio of the USGS largely mirrored Dr.

Garvey’s analysis described above. According to Dr. Garvey, the IAWA proposed DO standard

“works” by greatly reducing the percentage of violations in streams with high biological integrity

but still correctly identifying degraded streams. Exh. 16 at 3-4, Att. 3.

Board Findings on the IAWA Proposal

The Board agrees with the Garvey-Whiles report that the current Illinois DO standard,

adopted in 1972 is too simple to account for natural DO-concentration fluctuations and must be

updated based on available scientific information and in accordance with USEPA’s NCD.

The NCD recommends seasonal DO standards based on the anticipated presence or

absence of “early life stages” of fish. As the Assessment states, it is when aquatic organisms are

in their early life stages that they are most sensitive to hypoxia or low DO. It is therefore the

early life stages, in contrast to the later juvenile and adult stages, that require greater protection

through more stringent DO water quality standards. The IAWA proposal takes this approach.

The Board finds that a two-season DO standard, lacking in the current regulation, should be

adopted for Illinois.

The Board agrees with the Garvey-Whiles report that most inland waters in Illinois are

dominated by warmwater, non-salmonid species and that the NCD’s “warmwater” criteria

accordingly should be the primary basis for revising Illinois’ current DO standard. The NCD

criteria are 0.5 mg/L above the DO levels expected to cause impairment and include both mean

and minimum values. As the Garvey-Whiles report explains, the 7-day mean value is based on

“average levels over a period of seven days for early life stages of fish, when they are very

sensitive to oxygen stress,” while the daily minimum values are “recommended to protect against

acute stress or mortality of sensitive species.” Exh. 1 at 28.

For early life stages, the DO standard should require sufficient amounts of dissolved

oxygen to support the metabolic needs of eggs and larvae. The Assessment by Drs. Garvey and

Whiles recommends a daily minimum DO level of 5.0 mg/L and a 7-day mean DO level of 6.0

---

35

mg/L during early life stages. The Board generally agrees that these values, which are NCD-

recommended “warmwater” values, should be the DO water quality standards for early life

stages. DNR and IEPA propose the same DO standards, which they characterize as “Level 2”

standards, for most Illinois general use waters.

For the other life stages, the Board also agrees with Drs. Garvey and Whiles’

recommendation of a daily minimum DO level of 3.5 mg/L and a 7-day mean minimum DO

level of 4.0 mg/L. To account for the adult life stages and spawning times of common

warmwater fish taxa in Illinois, the daily minimum DO level of 3.5 mg/L is higher than the

NCD’s level of 3.0 mg/L. The joint DNR/IEPA proposal recommends the same DO standards

for its Level 2 waters. The Board also agrees with IAWA’s eventual position to include a 30-

day mean of 5.5 mg/L DO for other life stages, as recommended by the NCD and as proposed by

DNR and IEPA for Level 2 waters.

The Assessment states that a majority of Illinois warmwater fish species spawn between

spring and early summer (March through June). The Board further agrees with Drs. Garvey and

Whiles that the months of March through June should be included in the early life stages

timeframe, as IAWA proposes.

Accordingly, for first-notice, the Board will adopt a two-season general use water quality

standard for DO as proposed by IAWA, with the more stringent early life stages DO standards

applying from March 1 through June 30, but the Board will address below whether to also

include the month of July in the early life stages time period. DNR and IEPA agree that March

through June should be part of the early life stages, but also suggest including July.

Additionally, the Board will adopt for first notice the DO numeric values proposed by

IAWA as general use water quality standards for the early life stage and other life stages,

including the 30-day mean, but will address below whether enhanced numeric DO standards,

which DNR and IEPA characterize as “Level 1” standards, should be applied to certain Illinois

stream segments making up approximately 8% of general use stream miles.

Finally, the Garvey-Whiles report acknowledges that its recommended numeric DO

values are inappropriate for wetlands. The Board agrees and will discuss this issue below when

addressing the narrative DO standard proposed by the State agencies and agreed to by IAWA.

DISSOLVED OXYGEN DATA

IAWA’s View of the DO Data

USGS and IEPA DO Data From Eight Illinois Streams (2001-2003)

IAWA maintains that Dr. Garvey’s evaluation of DO monitoring data from eight streams

intensively sampled by USGS and IEPA show that the “proposed standard greatly reduces the

number of violations in unimpaired streams, such as Lusk Creek, while still capturing violations

in impaired streams.” PC 102 at 5. As discussed, Dr. Garvey states that DO levels in all eight

streams violated Illinois’ current DO standard at a frequency ranging from 1% to 65% of the

---

36

days. Exh. 9 at 3. These violations occurred in unimpaired stream segments and in stream

segments listed as impaired under Section 303(d) of the federal Clean Water Act.

Id.

at 4.

According to Dr. Garvey, IAWA’s proposed DO standard significantly reduced the

number of violations in unimpaired streams, but still resulted in violations in impaired streams,

including an increase in the frequency of violations in two of the severely oxygen-impaired

streams. Exh. 9 at 4. In other words, IAWA’s proposed standards “better capture” DO

violations in “truly impaired streams,” while the current Illinois DO standards result in frequent

violations in streams that are fully functioning with high quality habitats and diverse biotic

assemblages. Exh. 9, Att. 1 at 14.

IEPA Grab Sample Data (1994-2003) and Semi-Continuous Monitoring Data (2004-2005);

IAWA Semi-Continuous Monitoring Data (2005-2006)

Dr. Garvey reviewed data collected by IEPA, as well as data collected by IAWA

members. In Dr. Garvey’s opinion:

The most compelling results derive from stream segments slated for enhanced

dissolved oxygen protection by the proposed IDNR/IEPA two-tier approach. As I

analyzed these data, it became apparent that many of these segments likely violate

both the IDNR/IEPA and perhaps the IAWA proposed standards, even though

“enhanced oxygen” taxa are present in the streams. Exh. 35 at 4.

IEPA Data

.

Dr. Garvey states that IEPA provided him with “grab” DO data collected

during 1993 through 2003 “in streams that have fully met their aquatic use designation.” Exh. 35

at 5. IEPA also provided data from 2004 and 2005 collected with semi-continuous data logging

probes “in streams that have been tapped for inclusion in the ‘enhanced oxygen’ tier.”

Id

. IEPA

specifically describes this data as having been collected from “sites located on or within 1000

feet of a stream segment selected for the higher level of dissolved oxygen standards and recently

(2004 or later) rated as ‘full support’ for Aquatic Life Use.” Exh. 22 at 1.

Dr. Garvey states that the grab data demonstrate that median DO concentration declines

during June through August, relative to other months. Exh. 35 at 5, Att. 3. Given that these grab

samples were typically collected during the day, Dr. Garvey was not surprised that low DO

concentrations were not frequently found. Exh. 35 at 5.

Dr. Garvey states that the continuous data demonstrate that DO in “enhanced” stream

segments “more frequently declined below 5 mg/L and even occasionally below 3.5 mg/L.”

Exh. 35 at 6, Att. 3. He further points out that these low concentrations, which often violated

both the IAWA and DNR/IEPA proposed standards, typically occurred during the night through

dawn. According to Dr. Garvey, the enhanced-tier segments “more frequently (up to 20% of

observations) [violated] the DNR/EPA minimum of 5 mg/L during July than the IAWA

proposed standard of 3.5 mg/L during that month.”

Id

. The streams that contained “oxygen

sensitive” species “failed to meet the standard set for them by the IDNR/EPA proposal.”

Id.

at 6.

---

37

Dr. Garvey states that, according to IEPA’s Frevert, these data include results from 2005

when much of Illinois experienced a drought and therefore should be discounted because they

were collected in extreme conditions. Exh. 35 at 6. Dr. Garvey disagrees with this view, citing

“Liebig’s Law of the Minimum,” which Dr. Garvey describes as follows: “the distribution of all

living organisms will not be dictated by the average conditions, but rather the availability of the

most limiting condition.”

Id

. at 6-7.

According to Dr. Garvey, the occasional “worst case” scenario limiting the oxygen

available to local fauna determines the species composition and abundance present through time.

Dr. Garvey testified that the extreme drought conditions in the stream segments proposed for

enhanced protection “likely provided the worst case scenario and thereby insight into what the

acute minimum should be to support a diverse aquatic assemblage.” Exh. 35 at 7. Dr. Garvey

asserts that IAWA’s proposed minimum DO standard of 3.5 mg/L was “rarely [violated] in these

streams” and “likely is near that extreme lower limit.”

Id.

at 6-7, Att. 3.

IAWA Data

.

Several IAWA members installed semi-continuous DO loggers at stream

sites that are in segments proposed by DNR and IEPA for enhanced standards. Dr. Garvey

analyzed 2005 data from the Fox River and summer 2006 data from the DuPage, Kickapoo,

Rock, and Vermilion Rivers. Exh. 35 at 8. According to Dr. Garvey, “[p]robably the most

compelling result is the linear or log-linear relationship between daily discharge and median and

minimum daily dissolved oxygen concentrations in the streams.”

Id

., Att. 5. Dissolved oxygen

concentrations declined sharply with declining daily discharge in the Fox River during 2005.

Id

.

(Exhibit 5). In contrast, DO concentrations were either unrelated to discharge or negatively

related in the other streams during 2006.

Id

. Dr. Garvey believes that “this issue needs to be

incorporated into standard development and interpretation,” given that discharge can explain up

to 50% of the variation in DO concentrations.

Id.

at 9.

Dr. Garvey applied both the proposed DNR/IEPA enhanced DO standard and the

proposed IAWA DO standard to the semi-continuous data. According to Dr. Garvey, several

stream segments, including those in the DuPage, Fox, and Kickapoo Rivers, fail to meet the

season-dependent acute minima of either proposed standard, “even given the proposed enhanced

status of these systems.” Exh. 35 at 9, Att. 6. This outcome was not surprising to Dr. Garvey

because “some portions of the DuPage and Fox Rivers are currently listed with low dissolved

oxygen as a probable cause for impairment.”

Id

., Att. 5. Dr. Garvey points out, however, that

the Rock River, “which is listed as impaired due to low oxygen,” had no violations of the

minimum criteria.

Id.

, Att. 6.

Dr. Garvey found that seven-day mean DO standards proposed by IAWA and DNR/IEPA

were “generally insensitive.” Exh. 35 at 9, Att. 6. Dr. Garvey further testified:

Interestingly, the IAWA proposed 7-day minimum standard of 4 mg/L which

applies during July through February generated more violations than the

IDNR/IEPA 7-day mean minimum of 4.5 mg/L which starts in August . . . .

Although I did not expect this to occur, apparently applying the mean minimum

criterion during July as per the IAWA proposal is more sensitive. Exh. 35 at 9,

Att. 6.

---

38

Dr. Garvey states that the mean-minimum criterion appears to be “more sensitive” to frequent

declines in oxygen during the summer because the “daily variation in dissolved oxygen

concentrations differs more than the daily average (i.e., it is the variation not the mean that is

sensitive).”

Id

. at 10.

It is Dr. Garvey’s view that “it appears that many of these streams, particularly the Fox

River, fail to provide adequate oxygen for aquatic life during part of the summer.” Exh. 35 at 10.

Dr Garvey continues: “This causes me to question the linkage between the aquatic assemblages

used to select the sites for enhanced status and oxygen needs of the resident organisms.”

Id

.

Dr. Garvey concludes that “oxygen can become a limiting dissolved gas” for aquatic

organisms and, below some threshold, “we should expect to see deleterious effects and

reductions in species composition and abundance.” Exh. 35 at 10. Dr. Garvey states that all the

data he has reviewed suggest that:

a threshold does exist and that it occurs during the summer when concentrations

are less than or equal to 3 mg/L as stated in the NCD and the Garvey and Wiles

report. If a stream remains consistently above this level (i.e., never violates a 3.5

mg/L minimum), oxygen is no longer limiting for life and some other factor then

limits organisms . . . probably habitat.

Id

.

Continuing his testimony, Dr. Garvey states “I favor scrapping dissolved oxygen as a

standard altogether” because variable or low DO concentrations are “largely a symptom of

habitat problems and their interactions with other factors such as chemical and biological

pollutants . . . and . . . discharge.” Exh. 35 at 11. Because eliminating DO as a water quality

standard “is not currently a possibility,” Dr. Garvey asserts that “it appears that the set of

standards proposed in the Garvey and Whiles report stand the test of the data and should be

adopted in the interim.”

Id

.

Later, on December 18, 2006, at which time he was no longer under contract with IAWA,

Dr. Garvey filed a public comment as an “interested and concerned private citizen of Illinois,”

adding to his remarks on habitat. PC 94 at 1. Dr. Garvey discusses the issue of habitat as a

component of stream characteristics that allows systems to be resistant to changes in water

quality. He notes that habitat has a “spatial component” that must be sufficiently available to

allow an organism to “carry out its life history requirements and avoid local extinction.”

Id

.

This component may range from 10 kilometers for darters to thousands of kilometers for

sturgeon and paddlefish. Dr. Garvey states that occasional declines in DO in portions of an

organism’s “spatial extent” will not be a problem if the organism has “refuges” down- or up-

stream.

Id

.

However, continues Dr. Garvey, “habitat is becoming continually fragmented” due to

development and agricultural activities in Illinois. PC 94 at 1. Habitat fragmentation becomes a

problem during low DO levels when refuges are unavailable due to fragmentation:

---

39

To alleviate this problem, I would love to elevate the concentration within all

portions of Illinois streams to whatever level biologists want during whatever

time of the year is convenient for the resident organisms. Unfortunately, the

weight of the data collected to date suggests that dissolved oxygen concentrations

in streams sag during the summer when flow declines and temperature rises. This

is a natural tendency linked to physical factors currently beyond the biologist’s

control and are often independent of water quality.

Id

. at 1-2.

Dr. Garvey therefore urges caution in “developing rules that cannot be met” and recommends

that the regulatory focus be on habitat and its “internal connectivity,” with the goal of “creating

large stretches of connected streams with well-developed riparian corridors and stable,

functioning habitat.”

Id

. at 2.

IAWA Semi-Continuous Data from Fox River, East Branch DuPage River, and Salt Creek

(2006)

Dr. Garvey analyzed semi-continuous monitoring data from the Fox Metropolitan

Reclamation District for 2006 (to compare with data collected by this agency in 2005) and from

the DuPage River/Salt Creek Workgroup for the summer of 2006. Exh. 36 at 1. The three sites

on the Fox River providing data are in stream segments proposed for enhanced DO standards

under the DNR/IEPA proposal. The fives sites on the East Branch DuPage River and the three

sites on Salt Creek providing data are near but not within the DNR/IEPA-proposed stream

segments for enhanced DO protection.

Id

., Figure 1.

Dr. Garvey found that discharge in 2006 explained a portion of the variation in DO

concentrations in many of the rivers, but acknowledged that the “strength of the relationship was

weaker than that during the 2005 drought.” Exh. 36 at 1. Additionally, a “low discharge

typically constrained variation” in DO concentrations, keeping them at “relatively low levels.”

Id

.

According to Dr. Garvey, the Fox River sites within the segments proposed for enhanced

DO standards “typically fared worse in meeting both the IDNR/IEPA criteria and the IAWA

proposed criteria” than the Salt Creek and East Branch DuPage River sites. Exh. 36 at 1. Dr.

Garvey further found that:

the greatest disparity between the performance of the IDNR/IEPA and IAWA

proposed standards occurred during July, with the IDNR/IEPA standard

identifying up to ten times more “violations” than the IAWA proposal.

Id

.

Dr. Garvey also observed that some reaches were “clearly impaired” with DO concentrations

“extending far below 3 mg/L” (

e.g.

, East Branch DuPage River at St. Charles Road, and Salt

Creek at Fullersburg Road).

Id

. According to Dr. Garvey, “these problems typically occurred

before July and were identified similarly by both proposed standards.”

---

40

Dr. Garvey notes that “some congruence occurred” in daily DO concentrations “between

years across the three Fox River sites.” Exh. 36 at 2. This suggests to Dr. Garvey that DO

concentrations in river reaches are:

somewhat predictable among years, even given annual variation in climate (e.g .,

drought versus non-drought). This supports the hypothesis that organisms within

streams are likely able to “anticipate” (through selection of life history strategies,

reproductive allocation, etc.) seasonal changes in oxygen availability.

Id

.

Specifically, Dr. Garvey states that in July and August 2006, the Fox River sites within

the segments proposed for enhanced DO standards “performed poorly” under the proposed

minimum DO standards of both DNR/IEPA and IAWA. Exh. 36 at 3, Table 1. According to Dr.

Garvey’s analysis, the two proposed standards “fared similarly” on average across all sites,

except for July where the DNR/IEPA standard “generated 11% violations among sites whereas

the IAWA standard only generated 1%.”

Id

. Both proposed standards, continues Dr. Garvey:

found violations of the 7-day mean criterion, although the IAWA standard found

1% and the IDNR/IEPA found 6%, with about twice as many sites generating at

least one violation of the IDNR/IEPA standard. The Fox River enhanced sites

met this criterion for both standards.

Id

., Table 2.

The DNR/IEPA 7-day mean-minimum standard “found 22% violations of observations, of which

the Fox River in August was largely responsible,” according to Dr. Garvey.

Id

., Table 3. The

IAWA 7-day mean-minimum standard “also detected low values in the Fox River, although it

was less likely to generate violations for other sites and dates (17% for IAWA versus 46% for

IDNR/IEPA).”

Id

. Neither the DNR/IEPA nor the IAWA 30-day standard “detected many

violations.”

Id

., Table 4.

Dr. Garvey states that natural selection must favor traits that anticipate predictable

environmental conditions for organisms to become “adapted” to their environment. Exh. 36 at 3.

According to Dr. Garvey, fish and other organisms residing in low-gradient, warm-water streams

“should have traits including reproductive schedules that are related to oxygen, if oxygen

fluctuations within streams are somewhat predictable among years.”

Id

. Dr. Garvey’s

“conservative” analysis for the Fox River in 2005 (“an extreme drought year”) and 2006 (“a less

extreme year”) showed a relationship between daily values in each year, “suggesting that

seasonal changes in oxygen are predictable and may select for life histories that anticipate

summer oxygen sags.”

Id

., Figure 26

Further Comment on IEPA (2004-2005) and IAWA (2005-2006) Semi-Continuous DO Data

In his December 18, 2006 public comment filed simply as an interested citizen, Dr.

Garvey presents further findings of his analysis of the semi-continuous monitoring DO data

described above. Adding to his prior finding of the positive relationship between DO

concentration and discharge in several study streams, Dr. Garvey states that he had since

included water temperature as an additional factor. PC 94 at 1. He found that the rise in DO

concentration was simultaneous with a decline in temperature:

---

41

Knowing that water’s capacity for oxygen increases with declining temperature, it

further supports the supposition that increased flow plus reduced temperatures

(combined with increased aeration) are predominately involved in dissolved

oxygen dynamics in many Illinois streams. These physical factors cannot be

regulated by statute, although regulating instream flow might be an issue worth

some focus.

Id

.

IEPA Semi-Continuous DO Data (2006)

On April 24, 2007, IAWA submitted additional continuous DO measurement data for 32

Illinois river segments. The DO data was collected by IEPA during the summer and early fall of

2006. The sampled river segments include ten segments proposed to have “enhanced” DO

standards, including the DO value of 6.25 mg/L during the months of February through July.

Further, IAWA notes that all of the data was collected with continuous DO recorders during a

non-drought year. PC 109 at 1-2.

IAWA contends that the results of Dr. Garvey’s analysis of this IEPA DO data support

the IAWA’s proposed DO limits and the applicable timeframes. PC 109 at 2. IAWA maintains

that when the application of the DNR/IEPA-proposed limits to the data is compared with the

application of the IAWA-proposed limits, IAWA’s proposed standards “are a better fit and

generate fewer violations.”

Id

. “This is true for both the DO concentrations and the dates,”

according to IAWA.

Id.

Referring specifically to the stream segments proposed by DNR and IEPA to have

enhanced DO protection, IAWA states that the DO data indicate that some of the segments

violate the DO limits proposed by both IAWA and DNR/IEPA. PC 109 at 2. Given that the

State agencies suggest that these segments sustain a population of DO-sensitive species, IAWA

argues that this DO data:

calls into question the methods and assumptions made by the agencies in

determining which river segments should have the enhanced DO limits imposed

or which fish species are truly DO sensitive.

Id.

IAWA asserts that the 2006 DO monitoring data provide further support for its position

that the joint DNR/IEPA enhanced standard for certain stream segments “does not represent

natural dissolved oxygen conditions in Illinois waters.” PC 109 at 2. IAWA acknowledges that:

some waters in Illinois could be identified as requiring a different dissolved

oxygen average or minima for certain least disturbed waters. However, the

IAWA adamantly opposes establishing such criteria without the ground truthing

data to support that designation. *** [IAWA] remind[s] the Board the IEPA and

IDNR filed no data to support their joint proposal. They further testified that they

made no attempt to ground truth their proposal against collected data.

Id

. at 3.

---

42

Therefore, IAWA urges the Board to reject State agencies’ joint proposal and adopt IAWA’s

proposal, with the inclusion of the 30-day limit and the narrative standard.

Id

.

Dr. Garvey applied both the proposed IAWA standard and the proposed DNR/IEPA

“enhanced” standard to IEPA’s 2006 DO monitoring data from nine stream segments proposed

for “enhanced” status. PC 109 at 4. The river name and the DNR/IEPA stream segment

identification follow: Sugar Creek (BM-PS-C2); Hodges Creek (DAG-03); DuPage (GB-08);

DuPage (GB-18); South Branch Kishwaukee (PQC-06); Hampshire (PQFD-01); Hampshire

(PQFD-H-C3); East Branch Kishwaukee (PQI-10); and South Branch Kishwaukee (PQI-H-C5).

Id

.

Dr. Garvey states that with the exception of Sugar Creek, the proposed standards of

IAWA and DNR/IEPA generated similar results in terms of violations. In Sugar Creek, the

DNR/IEPA enhanced DO standard generated violations, while the IAWA standard did not. PC

109 at 6. Further, when DO data over the entire monitoring period for all of the stream segments

selected for enhanced protection were analyzed for the minimum DO criterion, 10% of the data

showed violations of the IAWA standard compared to 16% for the DNR/IEPA standard.

Id

. Dr.

Garvey’s report indicates that IAWA’s DO limit would have also generated violations in Sugar

Creek if the early life stages period were extended to include July, as proposed by the State

agencies.

Id.

at 6, Table 2.

DNR and IEPA’s View of the DO Data

DNR acknowledges that the continuous DO data provided in this record “from a handful

of locations throughout the State” helps to quantify the natural variability of DO, “thus justifying

the need to update the existing [DO] standards.” PC 96 at 7. DNR nevertheless maintains that:

it’s the biological data (fish and macroinvertebrates) and scientific literature that

describes their sensitivity to [DO] that is most relevant to deciding what the

appropriate standards need to be to fully protect aquatic life.

Id

.;

see also

Tr.4 at

90-92.

DNR explains that the joint recommendations were based on “identifying the aquatic life needs

for [DO].” PC 96 at 7. DNR asserts that the DO standards should be based solely on biological

data.

Id

., citing Tr.5 at 43-44.

According to DNR, direct use of other abiotic data is neither necessary nor appropriate to

establishing the standards. PC 96 at 7. DNR argues that while comparisons in the record of

current DO measurements with proposed DO standards are interesting, DNR believes that:

the basis for amending the [DO] standard should not be whether or not waters are

currently meeting the proposed standards, but rather, standards are set at levels to

meet aquatic life needs, including those life stages and species sensitive to [DO].

Id

.

---

43

IEPA similarly adds that the continuous DO monitoring data collected by IAWA

members has been presented “with little context regarding the meaning or possible

interpretations” of that data: “Some sites were able to meet the proposed standard and some

were not but no corresponding information about the actual biological conditions at the locations

was provided.” PC 103 at 10, 13, citing Tr.5 at 74-75. According to IEPA:

In a more conventional water quality standard proceeding, ambient data is not

used to drive the value set by the Board but to give the Board some insight into

whether or not the proposed standard is likely to be attained in most areas of the

State. In proposing standard changes to the Board, IEPA relies primarily on

laboratory studies that evaluate the acute and chronic impacts to aquatic life of

varying levels of a pollutant. The stakeholders to this proceeding seemed to agree

(until Dr. Garvey’s final pre-filed testimony) that the impacts of “desirable”

parameters like dissolved oxygen—as compared to toxics—are less accurately

measured by laboratory studies.

Id

. at 13-14.

IEPA also maintains that to better understand DO dynamics in Illinois streams, statewide

DO information is needed, “not just a limited set of waters receiving effluent discharges” as

provided by IAWA.

Id

. IEPA maintains that IAWA has never substantiated its claim that the

DO data supports IAWA’s proposal over that of DNR and IEPA. PC 103 at 12. Nor has IAWA,

according to IEPA, ever “explained to the Board how to make use of available [DO] data.”

Id

.

IEPA maintains that the newly available continuous DO monitoring data does not

“explain what conditions are expected to be found in healthy streams.” PC 103 at 14. IEPA

explains that the “patterns varied so greatly between the limited numbers of sites” for which data

was available that it was “impossible to draw meaningful conclusions about the needs of Illinois

fish from available ambient water quality data.”

Id

. IEPA and DNR, continues IEPA

accordingly did not use the available ambient DO data in developing their proposal.

Id

.

For example, regarding the USGS and IEPA DO data (2001-2003) discussed above,

IEPA notes that the “continuous DO data” is:

From a pilot project limited in scope and geographic coverage; only eight sites

were monitored intensively from about July 2001 to September 2003. Illinois

EPA does not believe it is valid to generalize from these limited results to a

statewide scale. Exh. 22 at 1.

Specifically, IEPA observes, four of the eight sites are on or near a General Use stream

segment proposed for enhanced DO: Lusk Creek; North Fork Vermilion River; Middle Fork

Vermilion River; and Mazon River. Exh. 22 at 2. Using the USGS/IEPA pilot-study data, only

one of the four sites meets the IAWA-proposed standards, as indicated in Dr. Garvey’s “Long

term dynamics of oxygen and temperature in Illinois streams” (July 2004) at Table 1.

Id

. IEPA

notes that, likewise, only one of the four sites meets the DNR/IEPA-proposed standards. These

Comparisons, however, continues IEPA, are “hampered by the fact that about 40% of the

‘useable’ results were rated only as ‘fair’ or ‘poor quality prior to manual data correction.”

Id

.

---

44

Therefore, approximately 40% of the measurements could be “inaccurate by as much as 0.5 to

2.0 mg/L,” according to IEPA. For this dataset, IEPA concludes:

Given the small number of sites monitored, the limited geographic coverage, and

the high potential for inaccuracy, these results have limited applicability for

discerning patterns of dissolved oxygen at stream sites throughout the state. Exh.

22 at 2.

For IEPA’s grab data (1994-2003) and continuous monitoring data (2004-2005), which

provided DO values from sites located on or near stream segments proposed for enhanced DO

protection, IEPA asserts that “little evidence exists to indicate that these General Use streams

typically cannot meet the IDNR/IEPA-recommended daily minimum (acute) standard.” Exh. 22

at 2. The dataset, however, “does not allow application of the more-important chronic dissolved

oxygen standards.”

Id

. Specifically, for the grab sample data from these stream sites, DO values

“were never below the IDNR/IEPA-recommended daily minimum standard for more than 6% of

sites statewide in any month.”

Id

. The grab data therefore, in IEPA’s estimation, “show little

inability to meet the DNR/IEPA recommended daily minimum (acute) standard.”

Id

.

IEPA maintains that the continuous monitoring data from 2004 “shows no evidence that

the IDNR/IEPA-recommended daily minimum standard cannot be met,” as none of the observed

daily minima are less than 4 .0 mg/L in August or September. Exh. 22 at 2. The 2005 data

“represent severe drought conditions over much of the state,” according to IEPA.

Id.

at 2-3. For

these “low-flow conditions,” IEPA continues, DO is:

expected to be atypically low with an increased chance of dropping below the

daily minimum standard. In such extreme conditions, aquatic life are expected to

be stressed. Illinois EPA recognizes that for the 2005 continuous-monitoring

results, most sites did not meet the recommended daily minimum standard.

Illinois EPA does not believe it is valid to generalize from the 2005 results to

more-typical years.

Id

. at 3.

Upon IAWA’s request, IEPA provided its most recent assessment information for stream

segments, known as “Assessment Units,” that meet all of the following:

1.

Rated as “impaired” for Aquatic Life Use in the IEPA 2006 Assessment

Database;

2.

DO is identified as a potential cause of the Aquatic Life Use impairment; and

3.

The Assessment Unit overlaps with a stream segment proposed to have enhanced

DO standards. Exh. 22 at 4;

see also

Tr.4 at 99.

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45

In all, twenty-two Assessment Units met these three criteria. Exh. 22 at 4. Smogor, a stream

biologist in IEPA’s Surface Water Section,

9

testified that the length of impaired streams

represented less than 3% of the length of streams proposed for enhanced DO protection. Tr.4 at

99-101, 110. IEPA expects the DNR/IEPA standards to improve its “ability to distinguish

between situations in which Aquatic Life Use is impaired due to low dissolved oxygen vs. not.”

Exh. 22 at 4.

IEPA therefore readily acknowledges that some of the stream segments proposed for

enhanced DO protection may currently be impaired for DO. Exh. 22 at 4; Resp. at 1. In fact,

most of IEPA’s 2006 continuous monitoring data came from impaired locations. PC 110 at 2. In

response to IAWA’s Streicher concluding that IEPA’s 2006 data support IAWA’s proposed

standard, IEPA states that Streicher has “misinterpreted” the data. Resp. at 1. The data consist

of continuous DO measurements taken at ten Illinois stream locations.

Id

. According to IEPA,

Streicher’s claim that the data demonstrate that IAWA’s standard is a “better fit” than the

DNR/IEPA proposed standard is “neither supported by the 2006 results nor consistent with Dr.

Garvey’s summary statement.”

Id

.

IEPA maintains that despite the many individual DO observations in the 2006 data, they

“predominantly are from impaired locations and therefore are not useful for evaluating the

relative efficacy of the two sets of dissolved oxygen standards.” PC 110 at 2. Nor was the

continuous monitoring designed to compare the effectiveness of the competing standards.

According to IEPA:

To be valid, such comparisons must be based on a larger, more representative

dataset from locations that are achieving their biological potential and thus more

likely to be harboring their full compliment of aquatic life.

Because eight of the ten locations likely were not meeting their biological

potential during the summer of 2006, it is not unreasonable to expect violations of

dissolved oxygen standards. It is not scientifically valid to interpret violations of

the IDNR/Illinois EPA standards at these locations as a worse fit than the IAWA-

proposed standards, which were also violated at most of these impaired locations.

Id

.

Other Participants’ Views of the DO Data

As noted above, Environmental Law & Policy Center, Prairie Rivers Network, and Sierra

Club maintain that an entire water body should not be allowed to fall to low DO levels just

because DO-sensitive species are present where a few samples with low DO concentrations were

collected. PC 101 at 5. Further, the presence of DO-sensitive fish in low DO reaches does not

9

Smogor has been with IEPA for approximately six years. Smogor has a Master of Science

degree in Fisheries and Wildlife Sciences from Virginia Polytechnic Institute and State

University, and a Bachelor of Science degree in Biology from the University of Illinois at

Champaign-Urbana. Tr.4 at 31.

---

46

prove that the population would not be affected if the entire segment were experienced low DO

levels, according to the environmental groups.

Id

. at 6.

CICI maintains that the data presented on behalf of IAWA’s testimony represents “sound

science which supports the petition and a proposed set of standards which are attainable.” PC 95

at 1.

Board Findings on the Use of Dissolved Oxygen Data

IAWA relies on Dr. Garvey’s analyses of DO monitoring data from several Illinois

streams to support its proposal and to question the validity of the joint DNR/IEPA proposal,

particularly the latter’s proposed “enhanced” DO standard for certain stream segments. As

discussed above, the DO datasets analyzed by Dr. Garvey include: (1) IEPA/USGS DO data

collected during the late summer of 2001 through the fall of 2003; (2) IEPA’s historical “grab”

DO data collected during 1994 through 2003; (3) IEPA’s semi-continuous DO data collected

during 2004-2005 in or near stream segments proposed to have enhanced DO standards; (4)

IAWA’s semi-continuous DO data collected during 2005-2006 in stream segments proposed to

have enhanced DO standards; and (5) IEPA’s semi-continuous data collected during 2006 in

stream segments proposed to have enhanced DO standards.

The Board appreciates the efforts of IAWA, and particularly those of Dr. Garvey, in

evaluating the available DO data to provide a better understanding of DO dynamics in the

monitored Illinois stream segments. After a thorough review, the Board makes a number of

findings below regarding Dr. Garvey’s analyses.

The Board finds that Dr. Garvey’s analysis of the IEPA/USGS DO data shows the

seasonal variation of DO levels with diurnal fluctuations in the monitored streams. As Dr.

Garvey emphasizes, applying the current Illinois DO standard to the DO data results in a higher

frequency of violations as compared to IAWA’s proposed DO standard. The Board further finds

that the results of the IEPA/USGS dataset suggest that the current DO standard fails to account

for the natural seasonal variation and diurnal fluctuation of DO. For purposes of this

rulemaking, however, the Board will not at this time draw broader conclusions from the

IEPA/USGS data, given the small number of sites monitored, the limited geographic coverage,

and the high proportion of data being rated as “fair” or “poor” quality. Exh. 22 at 2.

IEPA’s grab data from 1994 through 2003 for streams meeting the aquatic use

designation indicate a seasonal decline in DO during the summer months with an occasional

decline below 5 mg/L. This is consistent with IEPA’s assertion that the grab data show that

approximately 94% of the monitored stream sites rated as fully supporting aquatic life and

located on or near a stream segment selected for enhanced protection meet the enhanced daily

minimum DO standard of the joint DNR/IEPA proposal. Exh. 22 at 2; Tr.5 at 21-22.

The semi-continuous DO data evaluated by Dr. Garvey address stream segments

proposed by DNR and IEPA for enhanced DO standards. IEPA’s 2004-2005 data show that a

number of stream segments chosen to have enhanced DO standards fail to meet the both IAWA’s

and DNR/IEPA’s proposed DO standards. As expected, in July, the frequency of violations of

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47

the DNR/IEPA minimum standard of 5 mg/L was higher than that for IAWA’s minimum

standard of 3.5 mg/L. The semi-continuous DO data collected by IAWA members also indicate

that several stream segments designated for enhanced standards fail to meet the DO limits

proposed by either IAWA or DNR/IEPA. Regarding Dr. Garvey’s evaluation of the effect of

discharge on DO levels, the Board believes that it is an interesting exercise to test the hypothesis

that stream discharge drives the variation of DO in low gradient streams. The results of the

analysis, however, are not conclusive.

Concerning certain of IAWA’s semi-continuous DO data collected in stream segments

proposed for enhanced standards, the Board wishes to clarify the import of Dr. Garvey’s

testimony that IAWA’s proposal is “more sensitive” in particular circumstances than the

DNR/IEPA proposal. Specifically, Dr. Garvey states:

Interestingly, the IAWA proposed 7-day minimum standard of 4 mg/L which

applies during July through February generated more violations than the

IDNR/IEPA 7-day mean minimum of 4.5 mg/L which starts in August . . . .

Although I did not expect this to occur, apparently applying the mean minimum

criterion during July as per the IAWA proposal is more sensitive. Exh. 35 at 9,

Att. 6.

As this testimony indicates, Dr. Garvey is not in this instance comparing all of the two

proposals’ respective DO standards that would apply in July. In comparing IAWA’s 7-day mean

minimum with DNR/IEPA’s enhanced 7-day mean minimum, Dr. Garvey applied that IAWA

standard to three months of DO data (July, August, and September), but applied that DNR/IEPA

standard to only two months of DO data (August and September). Exh. 35, Att. 6, Table 3; Tr.5

at 152-54. As Dr. Garvey conceded at hearing, “it is kind of comparing apples to oranges in a lot

of ways.” Tr.5 at 153. Unlike the IAWA proposal, the joint DNR/IEPA proposal does not have

a 7-day mean minimum standard during July. The DNR/IEPA proposal has an enhanced 7-day

mean minimum of 4.5 mg/L that applies from August 1 to the end of February,

i.e.

, for seven

months, one month less than IAWA proposes to have its 7-day mean minimum of 4.0 mg/L

apply. In July, for example, IAWA also proposes a daily minimum DO standard of 3.5 mg/L,

while DNR and IEPA also propose an enhanced daily minimum DO standard of 5.0 mg/L. Exh.

35, Table 1

In the quoted passage above then, Dr. Garvey is not comparing the relative sensitivity of

the two competing proposals as a whole. Exh. 35, Tables 1-4. In fact, when later testifying

about other DO data (2006 semi-continuous monitoring data from the Fox Metropolitan

Reclamation District and the DuPage River/Salt Creek Workgroup), Dr. Garvey stated that “the

greatest disparity between the performance of the IDNR/IEPA and IAWA proposed standards

occurred during July, with the IDNR/IEPA standard identifying up to ten times more ‘violations’

than the IAWA proposal.” Exh. 36 at 1, 3, Tables 1-4 (in July, the DNR/IEPA minimum

standard “generated 11% violations among sites whereas the IAWA standard only generated

1%.”).

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48

Dr. Garvey’s analysis of IEPA’s 2006 DO data for nine stream segments proposed for

enhanced standards indicates that except for Sugar Creek, both the IAWA standard and the

DNR/IEPA standard generated similar results in terms of violations. For Sugar Creek, only the

DNR/IEPA standard generated violations. The IAWA’s DO standard would have also produced

violations in Sugar Creek, if IAWA’s proposed early life stage period included July. Moreover,

as noted by IEPA, the 2006 DO data are predominantly from impaired locations that are not

achieving their biological potential. PC 110 at 2. As such, the Board finds that the data are

inappropriate for evaluating the relative effectiveness of two sets of proposed DO standards.

In summary, the Board finds that the analyses of several DO monitoring datasets, which

include both grab and semi-continuous monitoring data, indicate that the current DO standard

does not account for the naturally-occuring seasonal variation and diurnal fluctuations of in-

stream DO concentrations. Beyond that, however, conclusions useful to this rulemaking cannot

be drawn at this time from these DO datasets.

DO monitoring data from several stream segments proposed for the enhanced DO

standard indicate that those stream segments violate both the IAWA and DNR/IEPA standards,

with the frequency of violations higher when applying the DNR/IEPA standard. The Board

cannot find that these results demonstrate that IAWA’s proposed DO standard is a better “fit”

than the DNR/IEPA standard, or

vice versa

for that matter. The data represent a small number of

monitoring locations, are of limited geographic coverage, and vary in quality and monitoring

objectives. Meaningfully interpreting DO data at various sampling locations is not possible

without corresponding information on biological conditions at those locations.

When setting water quality standards, the Board places significant weight on adopting a

standard that fully protects aquatic life, rather than simply trying to arrive at a standard that

would be met by current stream conditions. Frevert testified about IAWA’s questioning of how

stream segments with samples violating the proposed enhanced DO standard could yet be home

to “meaningful amounts” of DO-sensitive organisms:

The fact that they are lower doesn’t mean it’s a fully protective condition. It’s

possible that DO sensitive organisms are in place and under some degree of stress,

still hanging on to life, where we think a higher standard is appropriate anyway

pursuant to the Clean Water Act procedures and the need for the standard to be

protective. I don’t think we want to set a standard that’s on the ragged edge so the

slightest little deviation from that standard has the system collapse. *** That

doesn’t mean that every system where those higher organisms can live is at the

water quality condition we want or the standards we set . . . . [T]he fact that we

say a standard is warranted doesn’t mean it has to be an existing condition. Tr.5 at

30-31.

If stream segments do not meet the proposed DO standards upon adoption, the Board

expects that those stream segments would be assessed in accordance with the requirements of

Section 303(d) of the federal Clean Water Act. That provision requires states to identify and list

waters that do not meet applicable water quality standards or do not fully support their

designated uses. This list of impaired waters, known as the “303(d) list,” is submitted to USEPA

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49

for review and approval. The federal Clean Water Act also requires that a TMDL be developed

for each pollutant of an impaired water body. A TMDL must consider all potential sources of

pollutants, whether point or nonpoint. It also takes into account a margin of safety, which

reflects scientific uncertainty, as well as the effects of seasonal variation.

A new DO general use water quality standard in Illinois will impact these federally-driven

requirements and should be better tailored than the current DO standard for identifying waters

that are actually DO-impaired. One of the primary objectives of updating the standard is to

“bring in some pragmatism,” in the words of Frevert, and “pare back that list and help us find

those places that really do need the attention,” that is, “those streams with true DO problems.”

Tr.5 at 32.

DNR/IEPA PROPOSAL TO HAVE ENHANCED DO STANDARDS

FOR DESIGNATED STREAM SEGMENTS

DNR and IEPA seek to replace the current general use DO standard with two levels of

DO standards: Level 1 and Level 2. Each level would apply to one of two sets of general use

waters. PC 96 at 9; Exh. 23 at 1, Figure 1. One level of standards (Level 2) would apply to “the

large majority of General Use waters and is designed to ensure sufficient oxygen concentrations

for the aquatic life therein.” PC 96 at 9, quoting Exh. 23 at 1. Level 2 would require 5.0 mg/L

as a daily minimum and 6.0 mg/L as a daily mean averaged over 7 days during the months when

early life stages are present; for the rest of the year, the standards would be 3.5 mg/L as a daily

minimum, 4.0 mg/L as a daily minimum averaged over 7 days and 5.5 mg/L as a daily mean

averaged over 30 days. Tr.4 at 25-26. The State agencies, according to Frevert of IEPA,

“believe these concepts recognize the importance of maintaining sufficiently high . . . levels of

[DO] that ensure long-term support of healthy aquatic life communities.”

Id

. at 26.

Another higher level of standards (Level 1) would apply to:

a small, selected subset of General Use waters; these thresholds are designed to

protect Illinois’ most sensitive types and life stages of aquatic life that require

relatively higher [DO] concentrations. PC 96 at 9, quoting Exh. 23 at 1.

According to the State agencies, these higher DO standards include a daily minimum of 4.0

mg/L (0.5 mg/L higher than Level 2), a daily mean value averaged over a 7-day period of 6.25

mg/L (0.25 mg/L higher than Level 2), and a daily mean averaged over 30 days of 6.0 mg/L (0.5

mg/L higher than Level 2). Tr.4 at 26. The State agencies “identify about 8% of the length of

Illinois’ 71,394 stream miles as requiring these higher [DO] levels [Level 1] (based on stream

miles in the U.S. Geological Survey National Hydrography Dataset; see internet website:

//nhd.usgs.gov/). Exh. 23 at 1;

see also

Tr.4 at 32.

Overview of DNR/IEPA Process for Selecting Stream Segments To Have

Enhanced Dissolved Oxygen Standards

The State agencies established a process, Cross of DNR explains, to identify a “subset of

waters that warrant an incrementally higher [DO] standard.” Tr.4 at 40-41. DNR and IEPA took

the following steps:

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50

First, identify fish and macroinvertebrates (other than mussels) that are sensitive

to low DO;

Second, investigate fish and macroinvertebrate communities to determine four

biological measures: number of DO-sensitive fish species, proportion of

individual fish that are sensitive, number of DO-sensitive macroinvertebrate taxa,

and the proportion of individual macroinvertebrates that are sensitive;

Third, identify a threshold value for each of these four biological measures that

represented the typical amount known from healthy streams (i.e., the calculated

median value from sampling sites attaining the “full support” Clean Water Act

goal for aquatic life);

Fourth, identify sites with a meaningful amount of DO-sensitive organisms by

comparing values for each of the four biological measures with the established

threshold values, and selecting those sites where at least two of the four biological

measures equaled or

exceeded their corresponding threshold values.

Id

. at 3-4.

Using this process, 374 sampling sites were identified by DNR and IEPA as candidates

for enhanced DO protection of the 1,110 locations from which the State agencies had sampling

results. Tr.4 at 42. The State agencies then extrapolated these 374 sampling sites to stream

segments. According to DNR and IEPA, because of differing sampling methods for mussels,

mussels were separately addressed: the locations of two DO-sensitive mussel species largely

corresponded with the stream segments identified as needing an incrementally higher DO

standards, but additional stream segments were selected based on the presence of these two DO-

sensitive mussel species.

Id

. at 4-5.

Identifying DO-Sensitive Organisms

The State agencies believe that the warmwater NCD criteria are appropriate for most

Illinois waters, but they “provide insufficient protection for several species of Illinois stream fish

that inhabit a small but significant proportion of Illinois streams.” Exh. 23 at 10. DNR and

IEPA note that because the NCD warmwater criteria are based on “only a few tested

‘warmwater’ fish species,” the criteria are “protective only of fishes as sensitive as channel

catfish (early life stages) or largemouth bass (other life stages).”

Id

. According to the State

agencies, over 160 fish species inhabit Illinois streams.

Id

., citing Smith 1979; Illinois Natural

History Survey internet website:

www.inks.uiuc.edu/cbd/ilspecies/fishsplist.html. Absolute

sensitivity to low DO is unknown for a large majority of these species, according to the State

agencies.

Id

.

Some Illinois fish species, DNR and IEPA continue, have “sensitivity between

‘coldwater’ species (e.g., trout, salmon) and the two species that represent the threshold of

protection provided by USEPA’s (1986) ‘warmwater’ criteria.” Exh. 23 at 10. By way of

example, the State agencies point to smallmouth bass, which live in Illinois streams and “have

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51

been noted by USEPA (1986) as one of the most sensitive of the non-salmonid species tested.”

Id

. Because some Illinois fish have sensitivity between that of salmonids and largemouth bass or

channel catfish, DNR and IEPA conclude:

it is reasonable to expect that some Illinois waters inhabited by these

“intermediate” species would require dissolved oxygen standards higher than the

USEPA (1986) “warmwater” criteria but not as high as the “coldwater” criteria.

Id

.

According to the State agencies, the NCD “clearly recognizes this potential need”:

Some coolwater species may require more protection than that afforded by the

other life stage criteria for warmwater fish and it may be desirable to protect

sensitive coolwater species with the coldwater criteria. Many states have more

stringent [DO] standards for cooler waters, waters that contain either salmonids,

nonsalmonid coolwater fish, or the sensitive centrarchid, the smallmouth bass.

Id

.

at 10-11, quoting Exh. 2 (NCD) at 33.

Dr. Thomas, Chief of the Illinois Natural History Survey of DNR, testified about an

“intermediate” category between “warmwater” and “coldwater”:

The Garvey and Whiles report lumps Illinois fish into warm water and cold water.

Many biologists recognize that there are many fishes that would fall into a more

intermediate category of cool water fish. While there is no clear definition of

what species could be classified as cool water fish, there would be general

agreement that some fish communities thrive under conditions of more moderate

summer temperatures and in well oxygenated water. Some of our finer

Smallmouth bass streams would fall into this category, as would some of our

spring feed streams and some of our wooded streams and lakes, particularly in

northeastern Illinois. Tr.2 at 123.

The State agencies identified 31 Illinois stream-fish species that they believe are most

sensitive to low DO and therefore require DO minima higher than the NCD’s warmwater

criteria, including the American brook lamprey, the northern hog sucker, the rock bass, the

smallmouth bass, the banded sculpin, the bigeye chub, the brook stickleback, the stonecat, and

the rainbow darter. Exh. 23 at 11, Table 2.

DNR and IEPA selected these fish “based primarily on field-based rankings of species’

sensitivities to low [DO] (Rankin 2004).” Exh. 23 at 11. According to DNR and IEPA, Rankin

(2004) used field data of approximately 90 fish species collected from “hundreds of stream

locations in Ohio to determine a relative ranking of sensitivity for each species.”

Id

. The

rankings, continue the agencies, are based on “relations between observed [DO] concentrations

and the relative abundance of each fish species.”

Id

.

These rankings, DNR and IEPA maintain, provide “useful ‘real-world’ evidence of how

the occurrence and abundance of fish at a site are related to [DO] concentrations.” Exh. 23 at 11.

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52

The State agencies acknowledge, however, that because these relations are “correlative,” they do

not provide “absolute evidence that low [DO] caused low observed abundance.” The agencies

assert, nevertheless, that:

considering the limited information available on specific sensitivities of each of

Illinois’ many stream-fish species, Illinois DNR and Illinois EPA believe that

Rankin’s (2004) results pertain especially well to Illinois because over 80 of the

Ohio fish species also inhabit Illinois streams.

Id

. at 11.

In ranking each fish species by its relative sensitivity to low DO, DNR and IEPA explain,

Rankin (2004) “used weighted (by abundance) means of minimum [DO] concentrations.” Exh.

23 at 11-12. For each species, the State agencies continue, the weighted mean represents the

“typical daylight minimum [DO] concentration where the species tends to be most abundant.”

Id

. at 12.

According to Rankin (2004), DO is “perhaps the most important chemical constituent

limiting to aquatic life in streams across the U.S. [] because of its obvious importance for

respiration.” Exh. 16, Att. 4 at 1. Rankin notes that:

[m]ost state water quality standards have developed [DO] requirement[s] based on

the U.S. EPA (1986) criteria derivation guidelines using the most sensitive

species (to low DO) that inhabit these waters based on a relatively abundant

literature related to DO requirements.

Id

. at 1.

***

Criteria for dissolved oxygen for streams are typically structured as a two number

criteria with a minimum (never to [fall below]) value and as daily average values.

Even though most state dissolved oxygen criteria are based on methodologies

generated from controlled studies as outline[d] in the 1986 EPA guidelines (U.S.

EPA 1986)[,] some states have modified criteria on the basis of ambient field data

(Ohio EPA 1996) or have methodologies for site specific derivation of criteria due

to natural conditions . . . .

Id

. at 13.

Rankin (2004) acknowledges that there is “some variability related to multiple stressors that

influence the relationship of DO to aquatic communities in Ohio,” but maintains that there still is

a “clear threshold relationship between biological indicators of aquatic condition and ambient

[DO].” Exh. 16, Att. 4 at 3.

There is a “continuum of sensitivity” to ambient DO concentrations across species and

taxa that occur in Ohio, according to Rankin. Exh. 16, Att. 4 at 4. Rankin explains, for example,

that “moderately sensitive” species (

e.g.

, sand shiner, golden redhorse) are either not found or are

found at reduced abundance at sites with less than 3-4 mg/L of DO; two “highly sensitive”

species are “rarely (black redhorse), if ever (variegate darter) found at [DO] concentrations less

than 5 mg/L.”

Id

. Using ambient biological data, Rankin states, “to help or adjust criteria such

as [DO] takes advantage of the strength of well-founded biological monitoring to integrate the

often complex pathways of influence of DO.”

Id

. at 15.

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53

During direct communications on January 31, 2006, between Edward T. Rankin, Senior

Research Associate, Center for Applied Bioassessment and Biocriteria, Columbus, Ohio, and

Roy Smogor, IEPA, Springfield, Illinois, “Rankin caution[ed] against using these numeric values

directly; rather, he advise[d] that the relative rankings of the fish species are much more useful.”

Exh. 23 at 12;

see also

Tr.4 at 35.

Accordingly, DNR and IEPA used the relative DO sensitivities in Rankin (2004) and

selected rock bass as a “benchmark species because of its affinity to transitional warm/cool

waters.” Exh. 23 at 12; Tr.4 at 97-98. The State agencies then explain the interplay between

Rankin (2004), the NCD (USEPA, Chapman 1986), and their field experience to arrive at their

31 DO-sensitive fish species:

all species ranked as equally or more sensitive than rock bass were considered as

candidates for a list of Illinois fish species that are more sensitive to low [DO]

than channel catfish and largemouth bass and thus require [DO] minima higher

than the USEPA (1986) “warmwater” criteria. Rankin (2004) indicates that rock

bass are more sensitive to low [DO] than both channel catfish and largemouth

bass. *** Of 35 Illinois candidate species indicated in Rankin (2004) as equally

or more sensitive than rock bass, eleven were not selected for the list of Illinois

sensitive species. Based on their experience with these fishes in Illinois streams,

Illinois DNR fisheries biologists believe that these excluded species are not

especially sensitive to low [DO], relative to the other species considered. One

species (i.e., brook stickleback) indicated in Rankin (2004) as less sensitive than

rock bass, is included in the list of sensitive Illinois fishes. Additionally, five

species not addressed in Rankin (2004) (i.e., northern brook lamprey, banded

sculpin, longnose dace, Ozark minnow, and Iowa darter) were added to the list of

sensitive fish species in Illinois. These six species are included based on their

affinities to cool, well-oxygenated waters. USEPA (1986) acknowledges that

“there is apparently enough anecdotal information to suggest that many coolwater

species are more sensitive to [DO] depletion than are warmwater species” [Exh.

2(NCD) at 2] and therefore need incrementally higher protection for [DO]. Exh.

23 at 12-13.

As with fish, the State agencies continue, the NCD’s warmwater criteria for DO are

appropriate for most but not all Illinois waters, as they “provide insufficient protection for

several types of aquatic macroinvertebrates that inhabit a small but significant proportion of

Illinois streams.” Exh. 23 at 15. DNR and IEPA state that a “macroinvertebrate” means “any

invertebrate of a body size that would prevent it from passing through a sieve with mesh size of

595

μm

(i.e., U.S. Standard No .30)” and that typical Illinois stream macroinvertebrates include

insects, crayfish, scuds, sowbugs, worms, leeches, flatworms, snails, and mussels.

Id

. at 16. The

State agencies note that the NCD relied primarily two studies of only a few insects and that

scientific literature on how sensitive stream macroinvertebrates are to low DO is very limited.

Id

. at 15.

DNR and IEPA observe that the NCD, with its criteria primarily fish-based, nevertheless

recognizes that “[a]cutely lethal concentrations of [DO] appear to be higher for many aquatic

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54

insects than for fish.” Exh. 23 at 15, quoting Exh. 2 (NCD) at 29. The NCD’s recognition that

some macroinvertebrates are more DO-sensitive than fish, the State agencies continue, is

reflected in the NCD criteria, namely the “coldwater” daily minimum of 4.0 mg/L. The agencies

quote the NCD:

Although the acute lethal limit for salmonids is at or below 3 mg/l, the coldwater

minimum has been established at 4 mg/l because a significant proportion of the

insect species common to salmonid habitats are less tolerant of acute exposures to

low dissolved oxygen than are salmonids.

Id

. at 16, quoting Exh. 2 (NCD) at 33.

Because there are some Illinois macroinvertebrates, according to DNR and IEPA, “as sensitive to

low [DO] as those on which this USEPA (1986) ‘coldwater’ threshold was based[,] a daily

minimum of 4.0 mg/l is appropriate for Illinois waters inhabited by these types.”

Id

.

To determine the relative sensitivity to low DO of Illinois stream macroinvertebrates,

DNR and IEPA used the “Illinois EPA Macroinvertebrate Tolerance List,” which “reflects a long

history of working with macroinvertebrates in Illinois” to evaluate the effects and extent of

pollution. Exh. 23 at 16. The tolerance ratings are based primarily on organic pollution and go

from 0 to 11, with a zero rating assigned to taxa found only in “unaltered streams of high water

quality” and an 11 rating assigned to taxa known to occur in “severely polluted or disturbed

streams.”

Id

. at 17. The State agencies maintain that the tolerance rating, though not

corresponding to a DO concentration, “does provide a relative ranking of macroinvertebrate

sensitivity to primarily [DO].” Id. at 17-18.

The State agencies conclude that some Illinois macroinvertebrate taxa require higher DO

minima than the NCD’s warmwater criteria because:

USEPA ([NCD]1986; Table 6, p. 22) includes three macroinvertebrate taxa found

in Illinois that require 3.5 mg/l [DO] or higher to survive:

Baetisca laurentina

,

Hydropsyche

sp., and

Neophylax

sp. Additionally, Connolly et al. (2004) found

sub-lethal effects on mayflies (order

Ephemeroptera

) when [DO] was in the 25-

35% saturation range, which translates to a [DO] concentration of about 3.0 mg/l

at the temperatures studied. The sub-lethal effects were related to the failure of

some mayflies to emerge into the adult stage; thus, [DO] concentrations that drop

to 3.0 mg/l could potentially hamper the sustainability of mayfly populations.

Id

.

at 19.

The consensus of IEPA biologists was that macroinvertebrates with a tolerance rating of

3.5 or less (on the 0 to 11 scale) would require DO concentrations higher than the warmwater

criteria. Exh. 23 at 18. Ultimately, after review by DNR and IEPA staff, the State agencies

arrived at a list of macroinvertebrates that both have the 3.5 or less tolerance rating and occurred

in the IEPA macroinvertebrate samples collected from wadeable streams between 2001 and

2004.

Id

. at 19. The list includes mayflies, dragonflies, and beetles.

Id

. at 19, 21.

The State agencies evaluated mussels separately. Acknowledging that there is limited

scientific information, DNR identified two mussel species, the Rainbow and the Elephantear, as

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55

being “especially sensitive to low [DO] and thus requiring minima higher than the USEPA

(1986) ‘warmwater’ criteria.” Exh. 23 at 19. The agencies note that two studies, both from

2001, directly address the DO sensitivity of these two species. Concerning Rainbow mussels,

the study (Chen

et al

. (2001)) concluded that they:

generally live in well oxygenated stream and river riffles[,] exhibited the poorest

ability to regulate [oxygen consumption] under conditions of low oxygen

availability[, and] DO should probably be higher than 6 [mg/L] to ensure that

aerobic metabolism remains relatively unchanged.

Id

. at 19-20, citing Chen

et al

.

(2001) at 212, 214 .

Concerning Elephantear mussels, the study (Johnson

et al

. (2001)) concluded that they have “one

of the highest mortality rates (82%) of the species studied when exposed to [DO] concentrations

below 5 mg/l .”

Id

. at 20.

As discussed, DNR and IEPA “focus on relative rankings—rather than reported numeric

thresholds—of [DO] sensitivity as the most valid and useful approach” to select the Illinois fish

and macroinvertebrate types that require DO minima higher than the NCD warmwater criteria.

Exh. 23 at 22.

IEPA reiterates that the list or subset of General Use waters (about 8% of the General Use

stream miles) selected for higher DO standards resulted from the collaboration of DNR and

IEPA “experts who know and understand Illinois streams and their resident aquatic life.” PC

103 at 3-4. IEPA considers this list of stream segments a “primary feature of updating the

current [DO] standard” and “necessary to provide adequate protection for aquatic life in streams

throughout the entire state.”

Id

. at 3. IEPA stresses that these waters warrant DO levels higher

than USEPA’s “warmwater” criteria:

This subset of Illinois waters need higher standards because of a meaningful

amount of fish and macroinvertebrates that are more sensitive to low [DO] than

the relatively few organisms on which the USEPA’s “warmwater” criteria are

based. [citation omitted] IEPA and IDNR also testified that the [DO] necessary

to protect the aquatic life in this selected subset of General Use waters is

intermediate between the “coldwater” criteria and the “warmwater” criteria

recommended in USEPA’s [NCD].

Id

. at 4, citing Tr.4 at 33-4.

Smogor of IEPA testified that he conferred with Edward T. Rankin concerning how

Rankin’s research of Ohio fish and DO could assist DNR and IEPA in identifying fish species

that were especially sensitive to low DO. PC 103 at 4, citing Tr.4 at 35. According to IEPA, the

two State agencies “then worked together to analyze which stream sites had a meaningful

amount of sensitive organisms” (

id

.) and, in turn, “extrapolated the site-specific information” to

arrive at the subset of General Use streams proposed for enhanced protection (

id

., citing Tr.4 at

38-45). IEPA asserts that the joint proposal’s two levels of recommended DO standards are

“based directly on an understanding of the differences in [DO] sensitivities among the biological

communities occurring throughout Illinois.”

Id

. at 4-5, citing Tr.4 at 122.

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56

Identifying Sites With a “Meaningful Amount” of DO-Sensitive Organisms

Having identified DO-sensitive fish and macroinvertebrates, DNR and IEPA undertook

to identify specific stream sites in Illinois that have a “meaningful amount” of these DO-sensitive

organisms. Exh. 23 at 33. For fish, the State agencies used fish-community samples collected

by DNR from 1994 through 2005, which included data from 1028 stations, including 98 large-

river locations.

Id

. at 34. For macroinvertebrates other than mussels, the State agencies used

macroinvertebrate-community samples collected in wadeable streams from 2001 through 2004

and available on the IEPA BIOS, including data from 380 stations.

Id

. For mussels, the State

agencies used data compiled by the Illinois Natural History Survey from 1980 through 2005,

which are based on field collections and museum records. The mussel species examined

included those identified by DNR mussel experts as intolerant and riffle-dwelling and the stream

locations were limited to where live mussels were present.

Id

. In all, DNR and IEPA evaluated

1110 sites, 329 of which had both fish and macroinvertebrate data, while 699 of the sites had

only fish data and 82 of the sites had only macroinvertebrate data.

Id

. at 35.

The State agencies selected four biological measures to characterize each stream site,

namely the (1) number of sensitive fish species (or (2) macroinvertebrate taxa) and the (3)

proportion of individual fish (or (4) individual macroinvertebrates) that are sensitive. Exh. 23 at

35. (Mussels were separately addressed because their data did not comprise community

assessments.)

Id

. DNR and IEPA then determined threshold values for the biological measures

used to determine a meaningful amount of sensitive organisms “typical of healthy streams” by

calculating the median value from sites identified as “attaining the Clean Water Act goal for

aquatic life, referred to as full support.”

Id

. According to the agencies, full support waters were

chosen to limit the influence of environmental stresses:

including habitat and chemicals. In large rivers, full support sites were chosen

only from sites that fell on the main channel (i.e., not backwaters or side

channels). The number of full support sites used to calculate threshold values

varied from 45 sites in large rivers (i.e., Mississippi, Illinois, Wabash, and Ohio)

to 368 sites for fish in streams and non-large rivers, with 246 full support sites for

macroinvertebrates.

Id

.

The threshold values for the biological measures based on full support waters are as

follows: for fish in large rivers, two sensitive taxa and 2.63% as sensitive individuals; for fish in

non-large rivers or streams, four sensitive taxa and 9.3% as sensitive individuals; and for

macroinvertebrates (other than mussels), five sensitive taxa and 6.25% as sensitive individuals.

Exh. 23 at 36. The State agencies then compared each of the four biological measures for each

site with these threshold values:

Sites were selected as having a meaningful amount of sensitive organisms if at

least two of the four biological measures considered equaled or exceeded the

established threshold value for that measure. Sites that had fish-only or

macroinvertebrate-only data were eligible for selection if they met or exceeded

both thresholds for the available taxonomic group.

Id

.

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57

The State agencies explain that site-specific information for mussels is not directly

comparable because of differences in the methods used to collect mussels as opposed to other

macroinvertebrates in Illinois streams. Instead, DNR and IEPA selected a site as having a

meaningful amount of sensitive mussels present if the site was inhabited by at least one of the

two identified DO-sensitive mussel species,

i.e.

, Rainbow mussel or

Villosa iris

and Elephantear

mussel or

Elliptio crassidens

). Exh. 23 at 36.

Based on this analysis of fish and macroinvertebrates, DNR and IEPA identified 374

stream sites as having a meaningful amount of DO-sensitive organisms. Exh. 23 at 36, Figure 2.

Identifying Stream Segments for Enhanced DO Standards

DNR and IEPA take the position that having a meaningful amount of sensitive organisms

at a site reflects the “need for enhanced [DO] protection at the site

as well as upstream of the

site

.” Exh. 23 at 38 (emphasis added). The State agencies base their position on the “widely

documented knowledge that the physical and chemical properties of the water at a stream site

reflect upstream influences.”

Id

., citing,

e.g.

, Omemik

et al

. (1981), Smart

et al

. (1981);

Hunsaker and Levine (1995),

but see

Allan and Johnson (1997).

DNR and IEPA, however, are unaware of any criteria that can definitively identify

the “upstream extent of influence on [DO] for each site of concern.” Exh. 23 at 38. The

agencies therefore used what they describe as “some simple, practical constraints for

extrapolating from site-specific information to upstream stream segments,” all to arrive at those

stream segments expected to have “meaningful amounts of sensitive organisms” which, in the

agencies’ opinion, require “enhanced [DO] standards, i.e., minima higher than the USEPA

(1986) ‘warmwater’ criteria.”

Id

.

The information primarily relied on by the State agencies to select stream segments for

enhanced DO protection consisted of their sets of stream sites at which fish or macroinvertebrate

samples indicate the presence or lack of a meaningful amount of sensitive organisms, Illinois

streams that are part of the National Hydrography Dataset (1:100,000 map scale) sponsored by

the U.S. Geological Survey and USEPA, and U.S. Geological Survey 7.5-minute topographic

maps (1:24,000 map scale) for Illinois. Exh. 23 at 38-39.

For other than Illinois’ largest streams (Illinois River, Mississippi River, Ohio River, and

Wabash River), the agencies established several steps for extrapolating to determine whether

stream segments need greater DO protection. Exh. 23 at 39-40, Figure 3. First, proceeding

upstream, DNR and IEPA selected for enhanced protection any stream segment collocated with a

site that has a meaningful amount of DO-sensitive organisms.

Id

. Second, for stream segments

not collocated with, but upstream of, a site that has a meaningful amount of sensitive organisms,

the segment was selected for enhanced protection if the following four items were satisfied:

1.

The nearest downstream site with sufficient biological information has a

meaningful amount of sensitive organisms;

---

58

2.

The nearest downstream site with sufficient biological information is not a “large

river” site (to avoid taking the “concept of upstream influence to an impractical

extreme,” DNR and IEPA did not select all stream segments that occur upstream

of a large-river site with a meaningful amount of sensitive organisms);

3.

The stream segment is not smaller than “third order” in size, as most of the site-

based fish and macroinvertebrate information used came from third-order streams

or larger; and

4.

The stream segment is free-flowing, meaning “not obviously part of a lake,

reservoir, or large-river backwater.”

Id

.

Accordingly, the State agencies continue, for non-large rivers:

selection of stream segments for enhanced protection proceeded upstream from

any site that has a meaningful amount of sensitive organisms . . . . If a site was

encountered that has sufficient biological information that indicates lack of a

meaningful amount of sensitive organisms, then selection ceased about halfway to

that point or at a practical endpoint such as an obvious confluence . . . . In a few

cases, stream segments in the vicinity of a site that lacks a meaningful amount of

sensitive organisms nonetheless were selected for enhanced [DO] protection

because other nearby sites both upstream and downstream have meaningful

amounts of sensitive organisms. Exh. 23 at 40-41, Figures 3 and 4.

For large rivers, DNR and IEPA selected for enhanced DO protection those segments that

include a site with a meaningful amount of sensitive organisms. Exh. 23 at 41. For the part of

Mississippi River comprising navigational pools, DNR and IEPA selected all segments in the

same river pool as a site with a meaningful amount of sensitive organisms. For Illinois’ other

large rivers:

segments in the vicinity of a site that lacks a meaningful amount of sensitive

organisms nonetheless were selected for enhanced [DO] protection for situations

in which other nearby sites both upstream and downstream have meaningful

amounts of sensitive organisms.

Id

.

The State agencies then generated a list of all stream segments in Illinois selected by

them for enhanced DO protection. Using a geographic information system (GIS), each selected

stream segment was spatially located. The list provides the stream name and location

information on each selected stream segment, including the latitude and longitude values for

each starting and ending point and a unique segment number for each pair of starting and ending

points. Exh. 23 at 41, Figure 5; Exh. 21; PC 103 at 9..

In turn, the selected stream segments were reviewed by field biologists affiliated with

DNR and IEPA and evaluated against additional data on the presence of mussel species. Exh. 23

at 45. According to the State agencies, the limited evidence suggests that riffle-dwelling mussel

species are more DO-sensitive than other types (

id

., citing Johnson

et al

. (2001)), and USEPA

---

59

states in the NCD that “[i]n general, stream invertebrates that are requisite riffle-dwellers

probably have a higher [DO] requirement than other aquatic invertebrates” (

id

., citing Exh. 2

(NCD) at 3). DNR and IEPA state that seven intolerant mussel species were identified as

primarily riffle- dwelling by mussel experts in Illinois.

Id

., Table 6. The State agencies maintain

that their use of fish and non-mussel macroinvertebrate data to select the stream segments for

enhanced DO protection is corroborated by the mussels data, as 97% of the locations of riffle-

dwelling mussels occur on segments chosen for higher DO standards.

Id

.; Exh. 21; PC 103 at 9.

Responses to DNR/IEPA Proposal to Have Enhanced DO Standards

for Designated Stream Segments

The added feature of the joint DNR/IEPA proposal that Streicher of IAWA is most

concerned with is the enhanced DO concentrations for selected river segments. Exh. 32 at 7-8.

Streicher believes that the DO standard finally adopted in this proceeding should be a sound

dissolved oxygen regulation that will be used to develop stream use classifications. It will also

be used by IEPA in classifying streams as to attainment or impairment, used to develop TMDLs,

and used as the basis for future nutrient rulemaking.

Id

. at 5-6.

According to IAWA, the joint DNR/IEPA “enhanced” water approach should be deferred

until there is a scientifically-based, tiered-use proposal, relying on USEPA’s guidance for

developing tiered-use water quality standards. IAWA states that the record does not support the

need for the enhanced water DO standard or provide the basis for designating enhanced water

segments. PC 102 at 15.

As a compromise, IAWA states that if the Board finds any merit in the joint DNR/IEPA

proposal’s enhanced water segments, the Board should adopt only the appropriate DO

standard

for enhanced waters. IAWA asks that the Board not adopt the list of stream segments to receive

enhanced DO standards until IEPA or DNR present the scientific and technical basis to justify

including a segment or segments for enhanced protection. PC 102 at 15.

IAWA notes that it has already started work on the process of establishing appropriate

tiered-use water quality standards. PC 102 at 15. Specifically, IAWA has begun work to

develop a potential regulatory proposal to “replace the present one size fits all water quality

standard approach with tiered use criteria and appropriate standards.” Exh. 32 at 8. This effort

includes participation from stakeholders including DNR, IEPA, USEPA, and various

environmental groups. The work to date includes starting to identify the appropriate categories

based on existing and attainable uses, after which the water quality standards, including DO

concentrations, would be developed for each category.

Id

.

Streicher admits that those involved acknowledge that the tiered use process will be

complex and take a long time. Exh. 32 at 8-9. Streicher believes that the tiered use work

underway is the correct approach to resolving and addressing these complexities. He feels the

best approach to take may be using biological criteria as a tool to identify different categories, as

other states have and as suggested in the recently-circulated IEPA “White Paper.”

Id

. at 9.

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60

Streicher asserts that establishing specific numeric targets for DO without adequate data

to support them is “re-creating a flawed and unworkable standard.” Exh. 32 at 9. He “caution[s]

the Board to be very careful about adopting an arbitrary tiered use or what is called a ‘higher

level’ of waters in Illinois.”

Id

. at 9-10 (Streicher later again “caution[s] the Board to be very

careful about adopting this beginning of a tiered use system” without appropriately identifying

the “correct numbers, the correct stream use categories and the stream[] segments that are

appropriate for each category.” Exh. 32 at 11. Streicher believes that the participants in this

rulemaking seek to “fix a standard that most everyone now agrees is broken” and that standard

should not be replaced it with another standard that also has no data to support it.

Id

. at 10.

Streicher further states:

If the Board were to proceed establishing two tiers of dissolved oxygen standards

it could be setting itself up for a future workload when each of the suggested river

segments are analyzed and found to not need the suggested 6.25 mg/l dissolved

oxygen concentration. Exh. 32 at 10.

Streicher maintains that it “seems extremely arbitrary” how DNR and IEPA arrived at

identifying the segments for the enhanced protection.

Id

. He asserts that the proposed stream

segments have not been “subject to any ground truthing,” pointing out that no continuous DO

measurements have ever been performed to show that the suggested 6.25 mg/L DO concentration

is “either realistic or attainable in the proposed enhanced segments.”

Id

.

According to Streicher, IEPA emphasizes that only 8% of the total length of Illinois

stream miles would have the enhanced protection. Streicher argues that this 8% is “spread out

across the State in a very widely dispersed sort of pattern.” Exh. 32 at 10-11. Streicher believes

that these designations should be by “basin or at least by sub-basin.”

Id

. at 11. The data are

increasingly showing that “habitat should be the characteristic determining which waters receive

the designation.” Streicher refers to Dr. Mark David as:

one of the principal investigators working on an Illinois Department of

Agriculture project investigating the sources and effects of nutrients in Illinois

waters. Specifically, he is working with the Illinois Council for Food and

Agricultural Research (C-FAR). While that effort is not yet complete[,] Dr.

David was willing to state that his findings show that the greatest influence on

biological diversity in Illinois waters is habitat. Diverse and intact habitats result

in the greatest diversity of fish and macro-invertebrate communities.

Id.

at 11.

Streicher feels that the proposed 6.25 mg/L enhanced DO standard “is just wrong and is

just as broken” as Illinois’ current standard. Exh. 32 at 12. He believes it the 6.25 mg/L level is

unattainable “even in the least impaired river systems.”

Id

. Streicher emphasizes that IAWA

DO data, discussed above, show that the 6.25 mg/L value “was not always achieved.”

Id

.

Streicher poses four questions:

---

61

1.

“[H]ow can these river segments support the diversity of fish the IDNR suggests

are DO intolerant and [require] the protection of . . . a 6.25 mg/l average DO

standard, yet are found in river segments that in fact have been shown do not

achieve the 6.25 mg/l average?” Exh. 32 at 12.

2.

“Why is it we see lower DO levels yet still find the river supports a diverse

population of so called DO intolerant fish and other aquatic organisms?”

Id

.

3.

“[W]here are the data to support the agencies position?”

Id

.

4.

“Are we just finding a compromise that is not supported by any science?”

Id

.

CICI does not believe that DNR and IEPA have provided “the scientific evidence to

support . . . the establishment of river segments that would be subject to an even more stringent

standard . . . .” PC 95 at 1.

Thomas Murphy, Ph.D, commented on the NCD as a basis for the proposed standard. Dr.

Murphy is an emeritus professor of chemistry at DePaul University, and has been a board

member and technical advisor for the Lake Michigan Federation for approximately 20 years. Dr.

Murphy observes that USEPA’s 1986 NCD for DO (Chapman 1986) contains a disclaimer that

most of the data are based on laboratory studies that are not directly applicable to natural

situations. Dr. Murphy cites to the problems with this approach documented in the NCD: (1)

abundant food is not provided in the wild and fish expend more energy foraging there; (2) in

passing additional water over their gills to obtain needed oxygen, fish are exposed to increased

amounts of toxins; (3) fish are at increased risk of disease; and (4) fish are at increased risk of

predation. Of the three field studies discussed in the NCD (Exh. 2) at 19-20: “These three field

studies all indicate that . . . sites with dissolved oxygen concentrations below 5 mg/l have fish

assemblages with increasingly poorer population characteristics as the DO concentration

becomes lower.” Exh. 19 at 2.

Environmental Law & Policy Center, Prairie Rivers Network, and Sierra Club support

providing enhanced protection for waters with habitat for oxygen sensitive species. PC 101 at 1.

Further, these environmental groups agree with the State agencies’ assessment of the stream

segments.

Id

. at 1, 5. According to the environmental groups,

IAWA’s basic position against

giving “this very modest level of extra protection” to areas harboring DO-sensitive species is

to show that low DO concentrations have been found in these waters and argue that the

aquatic organisms there “must have adapted to the low DO levels.”

Id

. at 5. The

environmental groups maintain, however, that:

the fact that low DO conditions have been found at a few sites in streams with

DO sensitive fish does not mean that whole water body could be allowed to

fall to that DO level without ecological damage. Most obviously, if the whole

Fox River had hit the extremely low DO levels found by some monitoring

stations in 2005 and 2006, there would have been no live fish in the

river.

(Garvey, Nov. 2-3, 2006, Tr. 154-55) Plainly, at that time the fish in the affected

---

62

segments found a place to swim. (Pescitelli and Garvey, Nov. 2-3, 2006, Tr. 34,

155)

Id

. at 5-6.

The environmental groups assert that Leibig’s law of the minimum should not be used to “imply

that fish must be adapted to every environment, including unstable environments, in which they

can be found.”

Id

. at 6.

Environmental Law & Policy Center, Prairie Rivers Network, and Sierra Club further

assert that species populations may be “lost in particular areas and over time,” plentiful one year,

and scarce the next:

It would not have been correct for a person in 1870 to look at the huge number of

passenger pigeons still around and conclude that the bird had adapted to the

European settlement of North America. Similarly, the fact that DO sensitive fish

are present in a water segment despite findings of low DO in some reaches of the

segment for some period does not prove that the population is not already under

some stress and would not be affected if the entire segment were hit with such low

DO levels constantly or in combination with high flows, a series of droughts or

other stressors. (See Frevert, Cross, and Pescitelli, Nov. 2-3, 2006, Tr. 30-4) PC

101 at 6.

The Illinois Chapter of the American Fisheries Society states that it has reviewed the

record and believes that the DNR/IEPA procedures for “earmarking ‘Category I’ stream

segments are sound and scientifically based.” PC 100 at 1. According to the Illinois Chapter:

In formulating their recommendations, IDNR and IEPA relied heavily upon

information gleaned by their cooperative basin survey program that has long

served as a model for other states. The database amassed by their efforts spans

over 25 years and includes well over a thousand individual samples from Illinois

streams. Each sample includes data on fish, macroinvertebrates, habitat, and

water and sediment chemistry. Although this body of information forms the

backbone of the joint agency proposal, it is supplemented by dozens of scientific

literature sources, a state-of-the-art Geographic Information System (GIS), and, of

course, the collective experience of the dedicated field biologists within each

agency who have collected these data over the decades.

Id

. at 1-2.

DNR/IEPA Response to Criticism of Selecting Stream Segments for

Enhanced Dissolved Oxygen Protection

DNR takes issue with IAWA’s claims that the joint agency process to select stream

segments for enhanced DO standards was arbitrary. PC 96 at 3. According to DNR, USEPA’s

NCD accounts for differences in DO sensitivity among fish and macroinvertebrates by providing

“two different levels of DO criteria.”

Id

. DNR asserts that the joint-agency proposal for two

levels of numeric DO standards is based on “this sound, scientific foundation.

Id

. The State

agencies believe that the NCD provides the “basic framework” for determining a new DO

standard in Illinois. Exh. 23 at 7.

---

63

The State agencies recognize, however, that there are some limits in using information in

the NCD to revise Illinois DO standards. Exh. 23 at 5. Based on the information available at the

time, DNR and IEPA maintain, the NCD “represented a practicable way of accounting for how

different types and life stages of aquatic life were known to differ in their sensitivity to low

[DO].”

Id

. at 6-7. The DNR and IEPA, continues the agencies, “build on this [NCD]

framework” with information, made available since 1986, pertaining specifically to aquatic life

in Illinois waters.

Id

. at 5, 7.

DNR states that it and IEPA reviewed available scientific literature since 1986 “related

specifically to the DO tolerance of many types of fish and macroinvertebrates that inhabit Illinois

waters.” PC 96 at 3. Based on the literature and staff expertise, DNR continues, “we selected a

set of species more sensitive to low DO than those protected by the IAWA proposal.”

Id

., citing

Exh. 23 at 10-21. Again, DNR maintains that the IAWA proposal is inadequate because it “fails

to protect for species more sensitive to low [DO] than channel catfish and largemouth bass.”

Id

.

at 2.

Generally, according to the State agencies, to determine how the NCD criteria apply in

Illinois, DNR and IEPA addressed two main questions:

1)

Are the USEPA (1986) [DO] criteria sufficient for protecting the most

sensitive (to low [DO]) of the numerous types and life stages of fish and

macroinvertebrates that live in Illinois waters?

2)

If not, then what alternative [DO] criteria would ensure sufficient

protection and in which Illinois waters should these higher criteria apply?

Exh. 23 at 5-6.

The NCD, according to DNR and IEPA, accounts for differences in DO sensitivity

among types of fish or macroinvertebrates by providing “two different levels of [DO] criteria,

labeled as: ‘coldwater’ vs. ‘warmwater.’” Exh. 23 at 6. USEPA states in the NCD:

Criteria for coldwater fish are intended to apply to waters containing a population

of one or more species in the family Salmonidae (Bailey

et al

. 1970) or to waters

containing other coldwater or coolwater fish deemed by the user too be closer to

salmonids in sensitivity than to most warmwater species . . . The warmwater

criteria are necessary to protect early life stages of warmwater fish as sensitive as

channel catfish and to protect other life stages of fish as sensitive as largemouth

bass.

Id

., quoting Exh. 2 (NCD) at 33 (emphasis added).

The State agencies note that besides the differences among species, the NCD “accounts for

differences in [DO] sensitivity based on a fish’s life stage: early life stages vs. other.”

Id

.

According to DNR, the agencies established a detailed process for selecting “threshold

values for each biological measure to determine what constituted a meaningful amount of DO

sensitive organisms at a site.” PC 96 at 3. citing Exh. 23 at Table 5. In turn, DNR explains,

---

64

these threshold values were applied to “statewide biological databases” managed by DNR and

IEPA.

Id

. DNR states that the “extrapolation of site-based analytical results to identify specific

stream segments” requiring enhanced DO protection was conducted using “state-of-the-art

Geographical Information Systems, or GIS technology.”

Id

., citing Exh. 23 at 38-45. DNR

concludes that this record shows the joint recommendations to protect DO-sensitive Illinois

aquatic species are based on “sound and appropriate biological data collected statewide.”

Id

.

Specifically, besides the proposed Level 2 standards, which reflect the NCD according to

the State agencies, the proposed Level 1 standards (for approximately 8% of General Use stream

miles) include a “daily minimum” (acute) DO level of 4.0 mg/L “to protect Illinois aquatic life

that are most sensitive to low [DO] when early life stages of fish are absent.” Exh. 23 at 7. DNR

and IEPA assert that the 4.0 mg/L concentration is “based primarily on protecting the most-

sensitive macroinvertebrates” and is consistent with the NCD, which provides:

In summarizing the state of knowledge regarding the relative sensitivity of fish

and invertebrates to low [DO], it seems that some species of insects and other

crustaceans are killed at concentrations survived by all species of fish tested.

Thus, while most fish will survive exposure to 3 mg/l, many species of

invertebrates are killed by concentrations as high as 4 mg/l.

Id

. at 7-8, quoting

Exh. 2 (NCD) at 23.

For the same Level 1 waters, DNR and IEPA recommend chronic DO standards that, in

their words, “represent a practical balance.” Exh. 23 at 8. The State agencies used “fish species’

relative chronic sensitivities (Rankin 2004) and some limited information for

macroinvertebrates,” while acknowledging that they lacked specific information about “chronic

thresholds for the large majority of Illinois organisms.”

Id

. DNR and IEPA describe their

practical balance:

This balance primarily reflects that several Illinois fish species are intermediate in

chronic sensitivity between sensitive salmonids (i.e., trout, salmon) and the two

less sensitive species used as benchmarks for the USEPA (1986) “warmwater’

criteria (i.e., largemouth bass, channel catfish). Consequently, Illinois DNR and

Illinois EPA simply select [DO] concentrations halfway between the USEPA

(1986) “coldwater” and “warmwater” chronic levels. For example, for the period

when early life stages are absent, the USEPA “coldwater” threshold for the 7-day

mean of daily minima is 5.0 mg/l, and the analogous “warmwater” threshold is

4.0 mg/l. Illinois DNR and Illinois EPA select the midpoint, 4.5 mg/l . . ., as the

threshold for “intermediate” waters.

Id

.; Tr.4 at 33-34 (Smogor of IEPA testified

that “[s]ome Illinois waters require [DO] levels higher than U.S. EPA’s

‘warmwater’ criteria because of the presence of a meaningful amount of fish or

macroinvertebrates that are more sensitive to low [DO] than the relatively few

organisms on which U.S. EPA’s ‘warmwater’ criteria are primarily based.”).

DNR disputes Dr. Garvey’s critique of the joint agency approach to identifying streams

for enhanced protection based on DO-sensitive organisms. PC 96 at 6. Dr. Garvey testified:

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65

Only through experiments that establish causality between oxygen tolerance and

fish life processes can tolerance be assessed. Again, these issues have been

addressed in previous testimony when I described the research by Smale and

Rabeni published in the

Transactions of the American Fisheries Society

. Recall,

these investigators used a combination of lab assays and surveys to develop an

index of oxygen sensitivity in Missouri streams.

Id

., quoting Exh. 35 at 3-4.

According to the State agencies’ Technical Support Document (TSD), DNR and IEPA

relied primarily on field-based relations between DO and fish abundance (Rankin 2004) because

“traditional experimental information on [DO] is lacking for many Illinois fish species.” Exh. 23

at 22. DNR concedes that Smale and Rabeni used a combination of lab assays and surveys, but

maintains that Dr. Garvey “neglects to complete the story indicated by the evidence in Smale and

Rabeni, as well as other literature.” PC 96 at 6. The State agencies quote Smale and Rabeni in

the TSD:

Moreover, particularly for non-toxic substances like [DO], sole reliance on

laboratory-based acute thresholds is not recommended. For example, in a

laboratory-based study of stream-fish species’ acute sensitivities to low [DO],

Smale and Rabeni (1995) caution, “Considerable differences have been found

between laboratory tolerance values and lethal conditions in natural situations

(Moore 1942; Davis 1975). It may not be appropriate to use laboratory

measurements to predict specific, numerical values of either hypoxia or

hyperthermia that would be lethal to fish in the wild” (p. 699). Other scientists

have long recognized this difficulty in applying laboratory-based thresholds of

low dissolved oxygen as water-quality standards intended to protect fish in their

natural habitats (Aquatic Life Advisory Committee of the Ohio River Valley

Water Sanitation Commission 1956 ; Davis et al. 1979; USEPA 1986). Smale

and Rabeni (1995) further state, “The complexity of environmental challenges

faced by fish in natural situations does not inspire confidence in the applicability

of apparently simplistic and reductionist laboratory tolerance data . . . . ***” (p.

711). Exh. 23 at 22-23, quoting Smale and Rabeni (1995) at 699, 711.

DNR maintains that the joint agency approach in identifying Illinois species that are DO-

sensitive accounts for these concerns, which also pertain to analogous macroinvertebrate studies,

and is fully supported by the scientific literature. PC 96 at 6; Exh. 23 at 23.

Dr. Garvey further criticized the joint agency approach:

[T]he selection of streams based solely on associations between aquatic organisms

and average oxygen concentrations ignores other potential causal factors such as

habitat quality, gradient and temperature. Thus, coining these organisms as

[‘]oxygen sensitive[’] and then using them to select enhanced [tier] waters may

b[e] completely spurious. PC 96 at 6, quoting Exh. 35 at 3.

DNR points to the TSD for a “complete and accurate account of how [DNR] and [IEPA]

analyzed associations between fish and oxygen concentrations.” PC 96 at 6, citing Exh. 23 at

---

66

10-13. DNR asserts that the testimony and scientific literature presented in the record make clear

that the “coining of organisms as oxygen sensitive” is not only valid but a concept that the

USEPA NCD requires States to address.”

Id

. at 6-7.

DNR also responds to Dr. Garvey’s claims that standard development should be focused

primarily on the physical characteristics of streams. PC 96 at 8, quoting Exh. 35 at 5. Initially,

DNR notes that IAWA’s Streicher refers to the work of Dr. Mark David with the Illinois Council

for Food and Agricultural Research (CFAR).

Id

. at 7, citing Exh. 32 at 11. DNR mentions that

according to Streicher, Dr. David indicated that his findings so far, which are not complete,

indicate that the greatest influence on biological diversity in Illinois waters is habitat: “Diverse

and intact habitats result in the greatest diversity of fish and macro-invertebrate communities.”

Id

., quoting Exh. 32 at 11.

DNR states that it “agrees with this research” and has “accepted this premise for a long

time in management activities conducted to benefit the State’s natural resources.” PC 96 at 7-8.

However, DNR continues, “biodiversity is not the issue.”

Id

. at 8. DNR states that the presence

of DO-sensitive organisms at sites in Illinois does not imply that those sites are biologically

diverse.

Id

. According to DNR, Dr. Garvey “carries this premise even further” when he states

that “stream physical characteristics trump water quality and need to be the primary focus of

standard development.”

Id

. DNR disagrees with this “broad, general conclusion” and asserts

that:

Water quality improvements over the last 30 or so years, since the enactment of

the federal Clean Water Act, have resulted in major improvements in aquatic life

in waters such as the Illinois River, where habitat during the same time period has

been even further degraded.

Id

.

DNR also addresses one of the primary IAWA concerns with the joint agency proposal:

“How can river segments recommended for enhanced protection for [DO] have a meaningful

amount of DO sensitive taxa yet fail to meet the proposed [DO] standards?” PC 96 at 8. DNR

first states that DO concentration data and biological data “are very different,” as the former

“only reflects the condition at that point for that particular time period it was collected.”

Id

.

Biological data, on the other hand, “reflects what the organisms are exposed to regarding stresses

over time,” according to DNR.

Id

.

DNR explains that minor excursions in DO concentrations for limited time periods may

be tolerated. PC 96 at 8, citing Tr.5 at 30-35. If there are severe excursions over longer periods

of time, however, DNR asserts that “organisms will seek other refuges in nearby tributaries or

segments of stream and return when [DO] levels recover.”

Id

. A DNR field biologist testified

about observations of this phenomenon in the field “as a result of [DO] excursions.”

Id

. Steve

Pescitelli, a streams biologist with DNR in the northern section of Illinois, testified that during

the extreme drought conditions of 2005:

there was an intense alga bloom in the Fox River, and in our fall sport fish

sampling, we ran across the mouth of the creek and it was extreme high density

of fish, primarily large-bodied suckers who are DO sensitive, so there’s evidence

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67

that they do actually find refuge in these areas where there are higher oxygen

[concentrations]. Tr.5 at 33-34.

DNR also maintains that differing techniques for collecting DO concentration data and

biological data “over microhabitats (riffle, run, pools) can also easily account for this seemingly

apparent discrepancy in what the two data sets are indicating.” PC 96 at 8-9. Cross of DNR

testified that a wide variety of site-specific circumstances might account for “having DO

sensitive species present and still an excursion in the DO standard,” including “where the probe

is in comparison to where the biological samples were actually collected.” Tr.5 at 32-33. DNR

asserts:

Some of our most DO sensitive species can survive and thrive in waters that have

occasional excursions in dissolved oxygen, however they will not survive long in

a system that has dissolved oxygen excursions that occur frequently to 3.5 mg/L

and is at a 7 day mean minimum of 4.0 mg/L. PC 96 at 9.

IEPA emphasizes the testimony of Frevert, who testified that when DO levels fall below

the proposed standard, organisms may be under stress. PC 103 at 10, citing Tr.5 at at 30. IEPA

also emphasized the testimony of Pescitelli, the DNR field biologist who testified that DO-

sensitive fish seek areas of higher DO during times of low DO on the Fox River.

Id

., citing Tr.5

at 34.

DNR agrees with the general principles of “Leibig’s law,” as stated by Dr. Garvey, that

“the distribution of all living organisms will not be dictated by average conditions, but rather the

availability of the most limiting condition.” PC 96 at 10, quoting Exh. 35 at 6-7. DNR takes

issue, however, with the conclusion Dr. Garvey draws from Liebig’s law. Dr Garvey testified

that “[o]nly by identifying the limiting conditions, in other words the acute minimum oxygen

concentration can we determine what should be present through time.”

Id

. According to DNR,

Dr. Garvey’s conclusion:

fails to recognize the significance that Illinois’ environmental and natural resource

programs place in biological data. The biological data reflects multiple stresses

that may be present, and affecting the aquatic community function and structure

over time. This is why biological data has been critical for decades, and states

such as Ohio and Illinois have relied on the biological data to give a better

indication of stream quality as part of monitoring and assessment programs. It is

also the fundamental premise for the Illinois DNR and Illinois EPA joint

recommendations and why the extensive biological data from both agencies was

used in lieu of [DO] concentration data, or other abiotic data such as habitat and

temperature.

Id

.

IEPA disputes IAWA’s assertion that the proposed joint-agency enhanced standard of

6.25 mg/L for selected stream segments is baseless and nothing more than a compromise. PC

103 at 5 (citing Tr.5 at 76-78). IEPA comments that it and DNR took a “common-sense

approach” in arriving at 6.25 mg/L, which is the “midpoint” between USEPA’s “coldwater” and

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68

“warmwater” chronic criteria.

Id.

, citing Tr.4 at 111, Exh. 23 at 8. According to IEPA, the

scientific evidence in the record demonstrates that:

some types of fish and aquatic macroinvertebrates that live in Illinois streams

needed more protection than that provided by the USEPA “warmwater” criteria or

by the IAWA proposed standards. However, these Illinois organisms do not

necessarily need protection at the highest levels, as required by salmonids (i.e.

trout and salmon).

Id

., citing Tr.4 at 111.

IEPA maintains that selecting the midpoint number between the USEPA “warmwater” and

“coldwater” criteria is therefore “reasonable” and “technically sound.”

Id

.

Board Findings on Enhanced DO Standards for Designated Stream Segments

“Intermediate” Species

As stated above, the Board places significant weight on fully protecting aquatic life when

adopting water quality standards. The Board finds that IAWA’s proposed DO standard, which is

based on the NCD’s “warmwater” criteria, is protective of most aquatic organisms present in

general use waters of the State. The Board further finds that a small subset of general use waters,

which provide habitat to certain DO-sensitive species of fish and macroinvertebrates, including

mussels, requires an incrementally higher DO standard.

DO standards based on the NCD’s “warmwater criteria” sufficiently protect most aquatic

organisms in Illinois, but they do not adequately protect certain aquatic organisms with DO

sensitivity between “coldwater” species (

e.g.

, trout, salmon) and “warmwater” species (

e.g.

,

channel catfish, largemouth bass). The NCD recognizes that some “coolwater” species may

require more protection than that given by the “warmwater” criteria and may even need to be

protected with the “coldwater” criteria.

Illinois has over 160 fish species living in its waters. For example, Illinois streams are

inhabited by smallmouth bass, which the NCD identifies as one of the most DO-sensitive of the

non-salmonid species tested. Rock bass are also present in Illinois and are more sensitive to low

DO than channel catfish and largemouth bass, which species provided the bases for the NCD’s

“warmwater” criteria. The Board finds that to fully protect aquatic life in Illinois streams, the

DO standards must also protect “intermediate” organisms with DO sensitivity falling between

that of “coldwater” and “warmwater” species.

Identification of DO-Sensitive Organisms

The record demonstrates that several Illinois species of fish and macroinvertebrates,

including certain mussels, have DO sensitivity between the “coldwater” and “warmwater”

species considered in the NCD. As described earlier, DNR/IEPA relied in part on Rankin (2004)

to identify Illinois stream-fish believed to be most sensitive to low DO concentrations.

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69

Rankin (2004) includes a ranking of relative DO sensitivity for approximately 90 fish

species present in Ohio streams, based on extensive field data on fish species and in-stream DO

concentrations. The DO sensitivity ranking was established on the basis of DO concentration

and relative abundance of each fish species. Rankin (2004) states that there is strong threshold

relationship between biological indicators of aquatic conditions and ambient DO. The Board

recognizes that the correlative relationship between DO and fish abundance does not provide

absolute proof that low DO concentrations result in low abundance. However, given that there is

very limited information available on the specific sensitivities of each of Illinois’ fish species,

the Board finds that Rankin (2004) provides a good starting point for identifying DO-sensitive

Illinois fish species. Over 80 of the fish species listed in Rankin (2004) are also present in

Illinois streams.

The Board also finds that the State agencies appropriately selected the rock bass as the

benchmark species for identifying Illinois DO-sensitive fish species. Rock bass are more

sensitive to low DO than both channel catfish and largemouth bass, which represent the

“warmwater” threshold in the NCD. Further, according to DNR fisheries biologists, rock bass

have an “affinity to transitional warm/cool waters.” Exh. 23 at 12. On Rankin’s list of DO-

sensitive fish species, 35 fish species were equally or more sensitive than rock bass. Based on

the knowledge and experience of DNR fisheries biologists, 11 fish species were excluded from

the list of 35 Illinois candidate species and 6 Illinois-specific fish species not addressed in

Rankin (2004) were added to the list. Exh. 23 at 12.

As Cross of DNR testified:

Rankin 2004[] was provided to us from USEPA. We used that as the starting

point and tailored that to fish species that are also living in Illinois but may not be

living in Ohio, so we used it as a starting point, but we had a lot of additional input

from DNR fisheries biologists throughout the state that helped modify that basic

report from Ohio. The macroinvertebrates and mussel DO sensitive species did

not utilize the Ohio report at all. Those were based on other scientific data and

information . . . . Tr.5 at 29-30.

As indicated, in addition to fish, DNR and IEPA considered Illinois aquatic

macroinvertebrates that are sensitive to low DO. Certain types of macroinvertebrates that inhabit

a small proportion of Illinois streams require DO minima higher than the “warmwater” criteria

recommended by the NCD. USEPA recognizes the need for higher DO minima to protect

macroinvertebrates. The NCD’s “coldwater” minimum criteria are intended to be protective of

macroinvertebrates.

The State agencies used the tolerance ratings found in “Illinois EPA’s Macroinvertebrate

Tolerance List” to develop a relative ranking of macroinvertebrate sensitivity to DO. Exh. 23 at

16. Although IEPA’s tolerance ratings are based on organic pollution, the Board finds this

approach to be appropriate. There is very limited information in the literature concerning the

macroinvertebrate sensitivity to low DO. The record indicates, however, that macroinvertebrates

that are intolerant of polluted waters are generally intolerant of moderate DO reductions.

Id

. at

17. Additionally, the State agencies limited the DO-sensitive macroinvertebrates to those present

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70

in Illinois as indicated by IEPA’s sampling from wadeable Illinois streams between 2001 and

2004.

Id.

at 19. The State agencies identified 83 macroinvertebrate taxa as being sensitive to

low DO.

Finally, the State agencies also addressed mussels. Exh. 23 at 19-20. The Board finds

that the literature studies support their identification of two mussel species, the Rainbow and the

Elephantear, as requiring higher DO minima than the NCD “warmwater” criteria.

Sites with Meaningful Amounts of DO-Sensitive Organisms

Upon identifying DO-sensitive organisms present in Illinois streams, DNR and IEPA

developed a procedure to assess whether those organisms were present in meaningful amounts.

The State agencies considered extensive biological data on Illinois fish and macroinvertebrates,

evaluating data from 1,110 sites, of which 329 sites had both fish and macroinvertebrates data,

699 sites had only fish data, and 87 sites had only macroinvertebrate data. Exh. 23 at 34-35.

Further, to characterize each site for the presence of DO-sensitive species/taxa, DNR and IEPA

used four biological measures based on the number and proportion of sensitive species/taxa

present at a stream site. The threshold values chosen for the four biological measures were

premised on the presence of DO-sensitive species/taxa and their proportional abundance in

healthy “full support” streams. The threshold values were based on the median values of DO-

sensitive species/taxa at full support stream sampling sites, which included approximately 400

sites for fish and 246 sites for macroinvertebrates.

Id

. at 35.

The Board finds that a threshold based on the median value of DO-sensitive organisms

present in healthy streams is appropriate for determining whether a “meaningful amount” of such

organisms is present at each of the 1,110 stream sites evaluated by the State agencies. The use of

data from healthy streams reduces the influence of environmental stresses, including habitats and

chemicals. Tr.4 at 42. In addition, the Board finds that by selecting only those stream sites that

equaled or exceeded the threshold for at least two of the four biological measures, the State

agencies’ methodology ensured that only sites with meaningful amounts of DO-sensitive

organisms would qualify for the enhanced standard. The Board also finds that the presence of

one of the two DO-sensitive mussel species at a site constitutes a meaningful amount based on

the literature. DNR and IEPA identified 374 stream sites that have a meaningful amount of DO-

sensitive organisms. Exh. 23 at 36.

Stream Segments for Enhanced DO Protection

The Board finds that the presence of a meaningful amount of DO-sensitive organisms

requires enhanced DO protection both at that site and upstream of that site. A stream site’s

physical and chemical properties are influenced by upstream impacts. Criteria to definitively

determine the extent of upstream influence, however, are not available. DNR and IEPA

therefore used the map-based information describe above to identify stream segments expected

to have meaningful amounts of DO-sensitive organisms.

Under the DNR/IEPA joint proposal, for other than large rivers (Illinois River,

Mississippi River, Ohio River, and Wabash River), any stream segment collocated with a site

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71

that has a meaningful amount of DO-sensitive organisms was targeted for enhanced DO

protection. From that site, enhanced protection would extend upstream, continuing toward a site

where sufficient biological information indicates meaningful amounts of sensitive organisms are

lacking. The segment proposed for enhanced standards would culminate either at the halfway

point toward that site lacking a meaningful amount of sensitive organisms or at a practical

endpoint like an obvious confluence. Exh. 23 at 40.

For stream segments

not

collocated with a site having a meaningful amount of sensitive

organisms, the State agencies used four criteria to assess whether enhanced DO protection is

warranted. These criteria address the downstream presence of a meaningful amount of sensitive

organisms, the size of the stream, and the nature of the stream flow. Additionally, enhanced

protection was extended to segments in large rivers having a site with a meaningful amount of

sensitive organisms. For the Mississippi River navigational pools, all segments in the same river

pool as a site with a meaningful amount of sensitive organisms were selected. For the other large

rivers, segments in the vicinity of a site lacking a meaningful amount of sensitive organisms

were still selected for enhanced standards in order to address instances where nearby sites both

upstream and downstream do have meaningful amounts of sensitive organisms.

The Board finds that DNR and IEPA have taken a reasonable approach to identifying

stream segments that should be protected by enhanced DO standards. The approach takes into

account the biological data at a stream site and the upstream impacts on that site. The use of the

geographic information system (GIS) to spatially locate each stream segment designated for

enhanced protection ensures accurate delineation of each stream segment, with latitude and

longitude values for each starting and ending point. Approximately 8% of the length of Illinois

stream miles would be designated for enhanced protection. Exh. 23 at 1; Exh. 21; PC 103 at 9.

Enhanced DO Standards

The DNR/IEPA joint proposal identifies the enhanced DO standards as “Level 1”

standards and they would apply only in the main body of stream segments designated for

enhanced DO protection. The proposed “Level 2” DO standards would apply in the main body

of other streams, in the water above the thermocline of thermally stratified lakes and reservoirs,

and in the entire water column of unstratified lakes and reservoirs. As discussed below, a

narrative DO standard rather than any numeric DO standard would apply in quiescent and

isolated sectors of general use waters.

As for the enhanced DO or Level 1 standards themselves, during early life stages, the

State agencies propose a 7-day mean standard of 6.25 mg/L, which is 0.25 mg/L higher than the

corresponding Level 2 standard. Also during early life stages, the Level 1 daily minimum DO

standard is 5.0 mg/L, which is the same as the corresponding Level 2 standard.

For other life stages, DNR and IEPA propose an enhanced daily minimum DO standard

of 4.0 mg/L, an enhanced 7-day mean minimum DO standard of 4.5 mg/L, and an enhanced 30-

day mean DO standard of 6.0 mg/L. Each of these enhanced standards for other life stages is 0.5

mg/L higher than the corresponding Level 2 DO standard. Again, once IAWA agreed to the 30-

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72

day mean for other life stages, the DNR/IEPA-proposed Level 2 numeric values and the IAWA-

proposed numeric values became identical.

The Board notes that except for the Level 1 daily minimum standard of 5.0 mg/L during

early life stages and the Level 1 daily minimum standard of 4.0 mg/L during other life stages,

each of the enhanced DO standards represents the midpoint between the “warmwater” and

“coldwater” criteria recommended by USEPA in the NCD. Frevert of IEPA testified:

[T]he area where we sort of look for middle ground was in an average statistic,

not an instantaneous value. *** [W]e believe there’s more statistical significance

to a smaller increment if you look at it over an average period of time, and to just

arbitrarily pick one or the other [

i.e.

, the “warmwater” value or the “coldwater”

value] we thought was less sound judgment than finding a middle ground, and an

average figure will let you explore the smaller middle ground levels, so that was

our logic. Tr.4 at 105-06.

Smogor of IEPA added:

[T]here are certain species in Illinois that need more protection than the warm

water value but they didn’t quite need the protection of salmonids, trout and

salmon, and so realizing that they were somewhere in the middle, it -- to us it was

common sense to pick a middle value. Tr.4 at 111.

Because the enhanced standards are intended to protect aquatic organisms whose DO

sensitivity lies between that of “coldwater” and “warmwater” species, the Board finds it

appropriate to establish the mean value enhanced DO standards at the midpoint between the

“warmwater” and “coldwater” criteria. The Board finds that this is not merely a “compromise”

as argued by IAWA, but rather a practical approach reflecting common sense. Given the lack of

information on the specific DO sensitivities of Illinois fish species, the Board finds that this

approach is reasonable for setting the chronic enhanced DO standards.

The enhanced daily minimum standard of 5.0 mg/L during early life stages is identical to

the corresponding NCD “coldwater” and “warmwater” standard, as well as the corresponding

IAWA standard. Regarding the enhanced daily minimum standard of 4.0 mg/L during other life

stages, the Board finds that the proposed standard, which is at the same level recommended by

the NCD for “coldwater” species, is needed to protect the most sensitive Illinois

macroinvertebrates. Certain Illinois macroinvertebrates are as sensitive to low DO as some of

the taxa considered in establishing the NCD “coldwater” criteria. Tr.4 at 96.

Concluding Discussion on Enhanced DO Standards for Designated Stream Segments

The Board finds that DNR/IEPA’s proposal to have enhanced DO standards for

designated stream segments is reasonable and well-supported by this record. The process for

selecting these stream segments, which constitute roughly 8% of Illinois’ general use stream

miles, was rational, painstakingly detailed, and contrary to IAWA’s claims, not arbitrary.

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73

The State agencies have submitted extensive biological information and expert testimony

in support of the proposal. Rankin (2004) provides a reasonable basis for identifying DO-

sensitive fish species in Illinois streams. DNR and IEPA have established the presence of

“meaningful amounts” of DO-sensitive organisms in specified Illinois streams by relying on

extensive fish and macroinvertebrate data from approximately 1,100 stream sites across the

State. The Board further finds that to identify stream sites with meaningful amounts of DO-

sensitive organisms, the State agencies used reasonable biological measures and properly relied

on threshold values based on data from healthy streams. For the Board’s task today of setting

DO water quality standards at levels that meet the needs of aquatic life, the Board agrees with the

State agencies that the biological data and scientific literature on the DO-sensitivity of aquatic

life are more helpful than the limited DO datasets emphasized by IAWA.

The Board also agrees with the State agencies’ rationale for extrapolating stream sites

with a meaningful amount of DO-sensitive species to stream segments by considering upstream

influences on stream site conditions. Applying GIS to map the stream segments helps to ensure

the accuracy of the spatial location of each segment chosen for enhanced DO protection.

Proposed Appendix D to Part 302 lists these stream segments by basin name, segment name,

segment number, end points by latitude and longitude, and county. The Board solicits comment

on MWRDGC’s suggestion that these stream segments also be identified by “river mile.”

The Board finds that the enhanced DO standards proposed by DNR and IEPA are

appropriate for protecting Illinois aquatic organisms whose DO sensitivity is between that of

“warmwater” and “coldwater” species. An alternative to the DNR/IEPA-proposed enhanced

standards would be to protect Illinois DO-sensitive organisms using USEPA’s “coldwater”

criteria, as suggested in the NCD. The Board finds, however, that the joint proposal properly

adapts the NCD to Illinois streams based on the literature, the biological data, and the State

agencies’ vast field experience. As Frevert of IEPA testified, the joint proposal recommends “an

incrementally higher DO for aquatic communities that we know from the rest of our biological

science prefer higher DO conditions.” Tr.5 at 29-30. Of course, any discharger maintaining that

the enhanced DO standards are not necessary for a given stream segment may seek site-specific

relief from the Board as provided in the Act, such as by adjusted standard or site-specific rule

(415 ILCS 5/27, 28.1 (2006)).

Finally, the Board disagrees with IAWA’s position that any consideration of enhanced

DO standards must be deferred to a future rulemaking that addresses tiered-use water quality

standards. The Board is aware of both IAWA’s and IEPA’s efforts to develop a framework for

establishing tiered aquatic life use water quality standards. The development of those standards,

however, is at a very early stage and may take a long time to come to fruition. As Frevert of

IEPA testified:

That C-FAR [Council for Food and Agricultural Research] research or nutrient

research, some of the wetlands work we’re doing, some of our own evolution and

our monitoring programs, everybody here at the table recognizes we’re going to

know more about dissolved oxygen five or ten years from now than we do now,

and we fully expect that the dissolved oxygen standard is warranting of additional

review as time and knowledge moves forward. Our position is that we know

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74

enough now to know we can make a significant incremental improvement over

the standard we placed on the books [35] years ago. Not that it’s perfect, but that

it is a major step forward, and we intend to follow that up and we assume there’ll

be future steps. I want to caution everybody to wait for the next study because

there’s always going to be a next study. Tr.4 at 130.

Given the record in this rulemaking, the Board finds no reason to postpone adoption of

enhanced DO standards until the tiered aquatic life use standards are developed.

DNR/IEPA PROPOSAL TO INCLUDE JULY IN EARLY LIFE STAGES

DNR and IEPA state that USEPA’s recommendations in the NCD for DO “ are clear in

the need to protect for early life stages of fish.” Exh. 23 at 23. As the current Illinois DO water

quality standards were adopted years before the 1986 NCD, they “do not specifically address

these early life stages through a defined sensitive season.”

Id

. The State agencies recommend an

additional 30-day period (through July 31) as necessary to protect the early life stages of fish, in

contrast to IAWA’s recommended date of June 30. Tr.4 at 44.

Specifically, IEPA states that the joint agency proposal recommends a “longer early life

stages present period (i.e., extending through July 31)” to protect early life stages of fish and

“ensure the long-term survival and viability of Illinois fish species,” including smallmouth bass

and channel catfish. PC 103 at 6, citing Tr.4 at 44, Exh. 23 at 23-31. Cross of DNR states:

In general, by July 31, all late spawning fish species will have a substantial

majority of their spawning and fry development into dates when higher [DO]

standards will be in effect. Even though some larvae will be present into August,

Illinois DNR fisheries managers believe the July 31 date should not be

detrimental to the overall recruitment of a year class for fish species. Tr.4 at 44.

In contrast, according to Cross, IAWA’s proposed June 30 cutoff protects only the majority of

spring season spawns, but neglects to include the summer season spawns and a 30-day period to

protect post-hatch embryonic and yolk-sac fry development.

Id

.

DNR maintains that IAWA’s proposal to end the sensitive stage at June 30 “fails to

provide adequate protection for early life stages.” PC 96 at 3. USEPA’s 1986 NCD for DO,

IEPA notes, emphasizes the need to protect early life stages. PC 103 at 6. DNR also cites the

NCD, where USEPA defines early life stages including “all embryonic and larval stages and

juvenile forms to 30-days following hatching.” PC 96 at 3, citing Exh. 2 (NCD) at 34. DNR

maintains that the joint agency recommendation:

for an additional 30-day period (through July 31) necessary to protect early life

stages of fish, is based on extensive spawning information and data from six

authoritative texts which represent nearly 100 years of fish species spawning

information.

Id

. at 3-4, citing Exh. 23, Table 4.

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75

DNR emphasizes that there is a clear “biological need” to extend enhanced protection for early

life stages through July, rather than ending in June as IAWA proposes.

Id

. at 4. According to

DNR, the June 30 ending date of IAWA “neglects to include protection for post-hatch embryonic

and yolk-sac development as required by USEPA” in the NCD.

Id

., citing Exh. 2 (NCD). In

IEPA’s words, “[b]ased on the scientific literature, IAWA’s June 30 cut-off date likely fails to

provide sufficient time for the protection of post-hatch and embryonic and yolk-sac fry

development for several Illinois fish species.” PC 103 at 6, citing Tr.4 at 44, Exh. 23 at 26-31.

DNR contrasts its “extensive compilation of spawning information” (citing Exh. 23 at

Table 4) with the testimony of IAWA’s expert witness, Dr. Garvey, who “attempts to describe

spawning strategies in Illinois fish.” PC 96 at 4, citing Exh. 23 at 24. Many of the fish species

evaluated by Dr .Garvey, according to the State agencies, are “spring spawners.” Exh. 23 at 25.

Based on review of the literature for Illinois fish species, the State agencies addressed fish that

spawn either in the late spring (

i.e.

, may spawn into late June) or primarily in the summer.

Id

.

DNR and IEPA state that late spring spawners include channel catfish and smallmouth

bass, both of which are important for Illinois recreational fishing. Exh. 23 at 25. The agencies

note that:

•

Simon and Wallus (2003) stated that channel catfish “yolk-sac larvae and early juveniles

were collected mid-May through August with peaks in June and July in the Tennessee

and lower Ohio Rivers.”

Id

., quoting Simon and Wallus (2003) at 100.

•

The Michigan Department of Natural Resources (Michigan DNR) has documented

spawning periods for smallmouth bass between late April and early July in Michigan.

For smallmouth bass in Wisconsin, Simonson (2001) reports spawning periods from mid-

May through June.

According to the TSD, first-hand knowledge and field observations by DNR resource managers

support the findings of Simon and Wallus (2003), Michigan DNR (2004), and Simonson (2001).

Id

. In Illinois, the State agencies add, studies confirm that smallmouth bass spawn from mid-

April through late June with the main spawning period in June.

Id

., citing Smith (1979); Sallee

et al

. (1991).

To identify fish species that are summer spawners, DNR and IEPA relied on published

text of the natural history of fishes from Illinois (Smith 1979), Missouri (Pflieger 1997), Virginia

(Jenkins and Burkhead 1994), Tennessee (Etnier and Starves 1993), Wisconsin (Becker 1983),

and Arkansas (Robison and Buchanan 1988), focusing on species common to Illinois. Exh. 23 at

25-26. The State agencies defined the “spawning period” as the time of egg deposition and

fertilization, excluding the other early life stages of embryonic and fry development.

Id

. at 26,

Table 4.

The State agencies emphasize that two of the fish species with summer spawning periods,

the bigmouth shiner and the stonecat, were identified by DNR and IEPA fisheries scientists and

resource managers as “more-sensitive to low [DO] than most other Illinois stream-fish species.”

Exh. 23 at 26, Table 4. DNR and IEPA conclude that generally, by July 31:

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76

all late spawning fish species will have a substantial majority of their spawning

and fry development into dates when higher dissolved oxygen standards will be in

effect. Even though some larvae will be present into August, Illinois fisheries

managers believe the July 31 date should not be detrimental to the overall

recruitment of a year class for fish species.

Id

.

According to the State agencies, their proposed additional 30-day period is necessary to protect

the summer spawners and the early life stages of Illinois fish. The IAWA proposal of ending the

enhanced DO standard on June 30, continues DNR and IEPA, while protective of the majority of

spring spawners, “neglects to include the spawning period of the ‘summer’ spawners, and

neglects to include a 30-day period for protection of post-hatch embryonic and yolk-sac fry

development.”

Id

. at 26-27.

Dr. Thomas of DNR’s Illinois Natural History Survey stated that “many fish continue to

spawn until later in the summer, and sunfishes and bass in particular will re-nest a number of

times if early attempts to spawn fail or are delayed.” Exh. 13 at 2.

Responses to DNR/IEPA Proposal to Include July as an Early Life Stage

IAWA objects to what it characterizes as the joint DNR-IEPA proposal’s “arbitrary”

inclusion of July in the “cool weather months” that would be subject to the more stringent DO

limits. Exh. 32 at 14. Streicher states that the entire dataset presented shows that DO levels

throughout Illinois in July routinely fall below that found in the cooler months. He claims that

July is a “hot month with resulting increases in water temperature and lower DO saturation.”

Id

.

According to Streicher, including July in the early life stage:

means the establishment of a DO limitation that is currently not being attained, is

generally not attainable and one which will lead to expenditures of public funds to

attempt to meet an unattainable goal.

Id.

Dr. Garvey testified that latitudinal differences in spring warming in Illinois might

influence when sensitive early life stages are present. Exh. 16 at 5-6, Att. 5. Dr. Garvey

presented a December 12, 2004 draft study of his regarding how the temperature available for

spawning fish differed between northern and southern Illinois streams. Dr. Garvey found that by

June 30, most fish in southern Illinois likely have completed spawning, while most spawning in

northern Illinois may not be initiated until late June, with 95% initiating spawning by early July

in the north. Previous research published by Drs. Garvey and Stein shows that most production

of larval gizzard shad and bluegill occurred before July in central Ohio reservoirs.

Id.

at 6, Att.

7.

Dr. Garvey asserts that species spawning in the summer must be able to tolerate

occasionally low DO concentrations or they would not persist in nature. He says the fact that

streams in violation of the current DO standard are listed as containing sensitive species by DNR

supports this suggestion. Exh. 16 at 6. In February 2005, Dr. Garvey conducted an exercise to

show why offspring produced before June 30 would likely contribute disproportionately to fish

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77

production.

Id

., Att. 8. According to Dr. Garvey, this study was based on his peer-reviewed

literature demonstrating that the earliest spawned fish in an annual cohort likely have the highest

survival. A paper published by Drs. Garvey, Herra, and Leggett (2002) shows that only the

oldest and largest sunfish present during the fall survived to spring. Dr. Garvey states that this

pattern does appear to hold generally among species.

Id

., Att. 9. Dr. Garvey concludes that the

June 30 end point for the south and perhaps July 15 for the north is sufficient to provide

protection for most fishes spawning in the state.

Id.

at 7.

Dr. Garvey later suggests that “[e]vidence is mounting” that the majority of reproduction

of Illinois aquatic organisms either occurs before July 1 or late-spawning organisms have early

life stages tolerant of low DO. Exh. 35 at 3. According to Dr. Garvey, based on this record,

streams meeting IAWA’s proposed DO standards for July through February (daily acute

minimum of 3.5 mg/L and seven-day average of daily minima of 4 mg/L) appear to contain

robust and diverse biological assemblages while those streams that do not meet those standards

are typically impaired.

Id

.

IAWA argues that Dr. Garvey’s testimony supports the proposed date of June 30 to move

from the early life stage DO standard to the DO standard applicable for the remainder of the

year. PC 102 at 5. IAWA notes that Dr. Garvey’s analysis of existing data shows that DO levels

in July decline below 6.0 mg/L and 5.0 mg/L. While certain species continue to reproduce in

July and some species reproduce throughout the year, IAWA contends that Dr. Garvey’s

testimony shows that these species have substantial reproduction during cooler months to ensure

natural recruitment.

Id.

IAWA asserts that Dr. Garvey is a recognized expert whose testimony

should be controlling in deciding the cut-off date for the early life stage period.

Id.

at 14.

Considering the data on breeding periods for fish, Environmental Law & Policy Center,

Prairie Rivers Network, and Sierra Club support extending the early life stage through July to

protect July spawners:

IEPA/IDNR science is based on a lot more data than the IAWA Proposal as to

breeding periods for fish. IEPA and IDNR looked at species across the state and a

broad range of species. (Ex. 23) *** On the other hand, the IAWA Proposal, a

“one size fits all standard” as to the relevant water bodies, is based almost entirely

on studies of fish in southern lllinois supplemented recently by one study of a

backwater lake near Grafton. (Garvey, Nov. 2-3, 2006, Tr. 126) Further, IAWA

argues that most fish complete most of their breeding before July without

breaking down the larval periods for species (Garvey Nov. 2-3, 2006, Tr. 177-78)

or recognizing that the known late spawn may be important for species to

compensate for high flow periods in spring. (Pescitelli, Nov. 2-3, 2006, Tr. 35-7)

PC 101 at 3-4.

These environmental groups also respond to what they characterize as IAWA “implicitly”

arguing that it would be “cheaper for Illinois dischargers” to have a June 30 cut-off date for the

early life stages timeframe:

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78

This suggestion should be rejected because it is not supported by any economic

data. (See Streicher, Aug. 25, 2005, Tr. 61) Indeed, for this argument to make

sense there must be a number of dischargers that would face substantial costs to

meet the current standard in July that they would not incur if they only had to

meet the current standard in June and a 3.5 mg/L standard in July. It is

particularly hard to imagine how this could be done given, first, that many

dischargers are currently discharging to water bodies known to violate standards

in June, a month that everyone agrees should continue to be governed by the 5

mg/L minimum and, second, that IEPA only very rarely uses the DO standard in

permit writing. (Frevert, Nov. 2-3, 2006, Tr. 255-6)

Id

. at 4.

The Illinois Chapter of the American Fisheries Society states that it has reviewed the

record and believes that the DNR/IEPA procedures “to select a protected spawning/post-

spawning period . . . are sound and scientifically based.” PC 100 at 1.

DNR/IEPA Response to Criticism of Including July as an Early Life Stage

DNR disagrees with Dr. Garvey’s conclusions that:

Evidence is mounting that the majority of reproduction of aquatic organisms in

Illinois [either] occurs before July 1 (see Csoboth 2006 thesis, SIUC: Exhibit 1) or

late-spawning organisms have early life stages that are tolerant to low [DO]

concentrations. PC 96 at 4, quoting Exh. 35 at 3.

According to DNR, the Csoboth 2006 thesis, cited above by Dr. Garvey, is “limited in

geographic scope and cannot be extrapolated to all water types in all parts of the State.” PC 96 at

4. Further, DNR asserts that the testimony of DNR biologists and the extensive data and

scientific literature provided and cited by DNR contradict Dr. Garvey’s opinion about late-

spawning organisms having low-DO tolerant early life stages.

Id

., citing Tr.5 at 35-40, Exh. 23

at 24-26. DNR quotes from the USEPA’s NCD, which states: “The warm water criteria are

necessary to protect early life stages of warm water fish as sensitive as channel catfish . . . .”

Id

.

at 4-5, also citing Exh. 23 at 6. It is DNR’s position that it has provided evidence showing

channel catfish spawning through July 31 (citing Exh. 23 at Table 4), which “demonstrates that it

is absolutely necessary to provide the additional 30-day protection.”

Id

. at 5.

IEPA similarly disputes the testimony of Dr. Garvey that whatever spawning occurs

toward the end of the spawning period (in many cases July and August) is largely unimportant to

the well-being of the species. PC 103 at 7, citing Tr.3 at 79-100, Exh. 6, Attachment 8; Exh. 23

at 24. According to IEPA, Dr. Garvey’s position is not supported by the literature for Illinois

fish that spawn either in the late spring or primarily in the summer, or by the first-hand

knowledge and field observations of DNR.

Id

., citing Exh. 23 at 25-31.

IEPA maintains that protecting early life stages through July 31 ensures that “all later-

spawning fish species will have completed a substantial majority of their spawning and fry

development during the time when appropriate higher dissolved oxygen standards are in effect.”

PC 103 at 6, citing Tr.4 at 44, Exh. 23 at 23-31. According to IEPA, to protect all Illinois fish in

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79

General Use waters adequately, the early life stages must include “not only the typical early

spawning period, but also part of the late spawning” because “in some years [when early season

spawning is unsuccessful for any of many environmental causes], the relative importance of the

late-spawned fish is much greater than in a typical year when the majority of recruitment comes

from the earlier-spawned individuals.”

Id

. at 6-7, citing Exh. 23 at 24-25. In such instances,

according to the State agencies, the late season spawning “may provide the only individuals

recruited to the population in that year.” Exh. 23 at 24.

IEPA points out that the NCD allows for less restrictive DO standards during times of the

year when sensitive life stages of fish are not expected to be present, but only if the State can

demonstrate that the “recommended periods accurately reflect the conditions present in the

State.” PC 103 at 13. In this respect, IEPA asserts that IAWA’s proposal is “under-protective”

and that only by adopting July 31 as the end date for the sensitive life stage will the Board be

consistent with the NCD and protective of aquatic life.

Id

.

Board Findings on July as Early Life Stage

The Board agrees with both IAWA and the State agencies that the early life stages of fish

must be protected with higher DO standards, as recommended by the NCD. Although the NCD

recommends DO criteria for early life stages, the NCD does not recommend a specific time

period during which the higher standards should apply. According to the NCD, early life stages

include all embryonic and larval stages and all juvenile forms to 30-days following hatching.

Exh. 2 (NCD) at 34. The NCD states that the early life stages criteria are intended to apply only

where and when these stages occur.

Id.

at 33. The NCD therefore indicates that states should

adopt such standards when state-specific fish spawning information is available to define the

early life stages period.

As discussed above, the record contains sufficient fish spawning data and expert

testimony to support the adoption of DO standards for the protection of early life stages of fish in

Illinois. The only issue that needs to be resolved relates to defining the seasonal time period

when early life stages are present in Illinois waters. IAWA’s proposal specifies an early life

stages period starting on March 1 and ending on June 30. DNR and IEPA propose a longer

period by extending the early life stage period to the end of July.

IAWA relies primarily on Dr. Garvey’s testimony for limiting the early life stages period

to June 30. Dr. Garvey’s initial recommendation notes that IAWA’s proposed early life stages

time period protects spring spawning fish and accounts for fluctuations and reduced DO levels

during the summer months. Exh. 1 at 36. Further, Dr. Garvey contends that non-spring

spawners have adaptations that allow them to persist under natural oxygen concentrations

expected during the summer.

Id.

Dr. Garvey also asserts that occasional declines in the survival

of late spawning in species with extended reproduction have relatively small effects on overall

production. Exh. 16, Att. 8 at 4.

In his later testimony, Dr. Garvey states that:

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80

By June 30th, most fishes in Southern Illinois likely have completed spawning.

In the northern half of the state, most spawning may not be initiated until late

June. Spawning in the central portion of the state likely occurs during mid June.

Exh. 16 at 6.

While Dr. Garvey maintains his position that late spring or summer spawners persist in nature by

adapting to the natural decline in DO levels, he concludes that a “June 30th cutoff for the south

and perhaps July 15th for the north is sufficient to provide protection for most fishes spawning in

the state.”

Id.

at 7.

IAWA nevertheless maintains that inclusion of July in the early life stages period, which

includes the cooler weather months, is arbitrary because the DO monitoring data show that DO

levels in July fall below that found in cooler months. IAWA contends that the more stringent

DO standard applicable to early life stages is generally not attainable in July because of higher

water temperature and lower DO saturation.

The State agencies’ proposal extends early life stages to July 31 to afford protection for

late spring and summer spawners. DNR and IEPA note that Dr. Garvey’s assertions regarding

the significance of late spawning are valid only if critical spawning periods have passed and

early spawning is not affected by changes in typical natural conditions. Exh. 23 at 24. However,

in years where early spawning is affected by various environmental stressors, the State agencies

observe that recruitment to the population may come only from “late” season spawning.

Pescitelli, streams biologist with DNR, testified that while “we can debate the

percentages,” it is “clear that there’s lots of species that spawn after July 1.” Tr.5 at 36.

Pescitelli also took issue with Dr. Garvey’s position that late spawners contribute insignificantly

to the species population:

these smaller stream and river fish, the way they’re spawning, to avoid high flow,

and if you look at the flow records, at least in northern Illinois, there is -- June is

a very high flow month and that the enemy of a spawning fish is floods, and that

may not be true in a large river system, but in a small river system it’s true, and

these big flash floods disrupt the spawning act itself, flush eggs into areas that are

not suitable for incubation. So these fish actually delay spawning until July

and August when the flows are more stable. That’s their strategy, and for those

species, they contribute the largest portion of the population continuing into the

future, so there’s a whole -- and there’s a whole bunch of these species now.

They do, as Dr. Garvey said, spread their spawning out, some of them, at least,

and the reason for that is to try to hedge against high water flows, not, as he says,

to hedge against dissolved oxygen problems later in the season, because we don't

see those in a natural stream in August. We don’t see dissolved oxygen problems

in a natural stream; at least I never have. I have seen them in October and

November. There's a lot of leaf matter in the stream and there’s no flow, so

they’re not in a rush to get done before August because there’s no DO in August,

because there is plenty. Tr.5 at 36-37.

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81

The DNR/IEPA fisheries scientists evaluated the available literature for late spawning

Illinois fish to determine whether such species must be afforded additional protection. The

spawning data compiled by the State agencies show that a number fish species have late spring

or summer spawning periods. DNR and IEPA state that some of the late spawning species, such

as channel catfish and smallmouth bass, have recreational (fishing) significance in Illinois and

two of the summer spawning species, the bigmouth shiner and stonecat, have been identified as

being more sensitive to low DO than most other Illinois fish species. Exh. 23 at 25-26. The

State agencies contend that by extending the early life stages period to July 31, “all late

spawning fish species will have a substantial majority of their spawning and fry development

into dates when higher dissolve oxygen standards will be in effect.”

Id.

at 26.

The Board finds that while the fish spawning data and expert testimony presented by

IAWA generally address the protection of early life stages of spring spawners, the proposal does

not provide adequate protection for late spring and summer spawners. Moreover, even for the

majority of spring spawners, the early life stages time period proposed by IAWA does not

include a 30-day period to protect post-hatch embryonic and yolk-sac fry development. The

Board believes that the early life stages time period must be established on the basis of fish

spawning and fry development data that address Illinois fish assemblages, including late spring

and summer spawners.

The Board finds that including July in the early life stages time period, as proposed by

the State agencies, provides important protectionto Illinois fish species that spawn during the late

spring and summer. Significantly, the July 31 end date affords 30-day post hatch protection for

spring spawners, which was not taken into account by the IAWA proposal. The July 31 end date

comes 16 days after the July 15th end date suggested by Dr. Garvey for northern streams. Given

that a large number of Illinois fish species spawn during the late spring and summer, and some of

them have recreational significance, the Board finds it appropriate to extend the early life stages

period through July.

Finally, the Board reiterates that when adopting a water quality standard, the Board

places significant weight on fully protecting aquatic life. The Board will not decline to extend

critical DO protection because of IAWA concerns about the attainability of more stringent early

life stages standards in July. This is particularly so as IAWA’s assertions are based on DO data

that is, as discussed above, from a small number of monitoring locations, limited in geographic

coverage, and varying in quality and monitoring objectives.

DNR/IEPA PROPOSAL FOR A NARRATIVE STANDARD

DNR and IEPA observe that their proposed DO standards include “absolute,

instantaneous thresholds called ‘daily minima.’” Exh. 23 at 32. The State agencies

acknowledge, however, that this type of “acute water-quality standard reflects an unrealistic,

idealized expectation” because:

In reality, under some natural conditions, [DO] concentrations are likely to drop

to levels normally expected to be acutely harmful to aquatic life. In surface

waters, [DO] concentrations are influenced directly or indirectly by numerous

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82

interacting environmental factors, including temperature, atmospheric pressure,

light intensity, ice cover, water clarity, and photosynthesis and respiration of

plants and animals. Particular combinations of these factors can result in low

[DO] levels unrelated to human impacts.

Id

.

According to DNR and IEPA, stratification in lakes and low flow in streams during

summer and fall, for example, can result in DO “depression.” Exh. 23 at 32, citing Hynes

(1970). Aquatic life can be meaningfully affected, continue the agencies, by “acute or chronic

differences as small as 0.5 to 1.0 mg/l” DO.

Id

. These small but critical differences “coupled

with relatively high natural variability confound the ability to select [DO] thresholds (i.e., water

quality standards) that can consistently distinguish deleterious human impacts from natural

influences on aquatic life.”

Id

. DNR and IEPA further state that these difficulties have been

widely recognized by developers of DO water quality standards (Aquatic Life Advisory

Committee of the Ohio River Valley Water Sanitation Commission (1955); Davis (1975); Davis

et al

. (1979); Truelson (1997)), including USEPA in its NCD.

Id

. at 32-33, citing Exh. 2 (NCD)

at 28.

DNR and IEPA maintain that useful DO standards for Illinois must accommodate “the

reality of how [DO] naturally varies through time and across locations in Illinois.” Exh. 23 at 33.

The State agencies propose an “additional narrative part of the [DO] standards” to address these

concerns.

Id

. Frevert of IEPA testified that the numeric standards:

apply in the main body of a stream. In other words, we’re not restricting

applicability . . . of those values to either pool or riffle stretches; rather, it applies

throughout. The obvious departure from this uniform application applies to

isolated areas such as backwater sloughs and portions of lakes and reservoirs

below the thermocline where lower oxygen concentrations can be expected to

occur naturally. Tr.4 at 27.

Frevert clarified that the “offensive conditions” language, as proposed by the

State agencies, would (1) apply in wetlands, sloughs, backwaters, and below the

thermocline in lakes and reservoirs, and (2) not modify the application of 35 Ill. Adm.

Code 302.203. Tr.5 at 15-16. The first sentence of the proposed DNR/IEPA narrative

standard, according to Frevert, was included to “show that we’re not abandoning the

existing standard for offensive conditions.” Tr.4 at 62.

Environmental Law & Policy Center, Prairie Rivers Network, and Sierra Club express

concern about how the various terms in the narrative standard would be interpreted. The

environmental groups identify terms such as “quiescent”, “lake” and “isolated” as vague. PC

101 at 7. According to Frevert’s testimony, the proposed use of the word “quiescent” is

“intended to describe the state of motion of a water that is still and where there is no or minimal

mixing or diffusion at the air/water interface,” while the term “isolated sector” is “intended to

describe a water body that is separate from the main river or stream flow [and is] not intended to

refer to the presence of dry areas between the main river and the isolated sector.” Tr.5 at 13.

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The State agencies propose to add a definition of “thermocline,” meaning “the plane of

maximum rate of decrease of temperature with respect to depth in a thermally stratified body of

water.” PC 103 at 7. Frevert testified that waters with “thermoclines” are waters that

“seasonally thermally stratify and in which a maximum rate of temperature change with depth

can be determined by measuring temperature at equal depth intervals from the surface to the

bottom.” Tr.5 at 12. Smogor of IEPA testified that a “thermally stratified” body of water is one:

that because of differences in temperature from the surface to the bottom, the

water takes on a different density with temperature, and in the summer that

happens and sometimes also happens in the winter. So water has certain

properties whereas it lowers in temperature towards about 4 degrees celsius, it

increases in density, and as it goes from 4 degrees celsius down to 0 degrees

celsius, actually, its density decreases. That’s why ice floats. So as water gets

colder, it sinks to the bottom until it gets even colder, and then it goes back to the

top, and that's why water freezes from the top down. In the summer and in the

winter, because of these density differences, there's a stratification. There’s strata

of different densities of water with the heaviest water on the bottom, the most

dense water on the bottom and the least dense water on the top. Tr.4 at 53.

Matt Short of IEPA’s Surface Water Section testified that when IEPA conducts lake surveys, it

measures water temperature, DO, pH, and conductivity “every two feet, starting at the surface

and all the way to the bottom, until two feet off the bottom.” Tr.5 at 20.

Frevert testified about the numeric DO standards’ inapplicability below the thermocline:

the DO standards apply in those upper stratas. While we cannot expect to meet

DO in the lower isolated water bodies simply because the aerating dynamics don’t

exist, it’s clear above that thermocline, and those DO standards do apply. *** A

body that’s deep enough and the energy or the dynamics are not conditions to

have thorough mixing, you’re going to have a zone in a lower area which cannot

maintain oxygen. We’re trying to acknowledge that. Tr.4 at 58-59.

A lake also can be stratified at some times of the year but then not at other times, Frevert added:

Seasonally the lake can be fully mixed and you don't have a stratified condition,

so you also need to show -- if you’re applying the [numeric DO] standard above

stratification, above the thermocline, there needs to be a thermocline for that

concept to hold, and sometimes there isn’t. Tr.4 at 60.

Frevert described the “natural ecological functions” of lakes and reservoirs below a

thermocline as follows: transforming and decomposing organic material and mineralizing

inorganic particles. Tr.5 at 15. As for “resident ecological communities” that are natural below

a thermocline in a lake or reservoir, Frevert commented: “Benthos consists primarily of midges

and worms. Other dipterans may also use this zone but are less common.”

Id

.

Frevert further testified on the scope and meaning of the narrative standard:

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Regarding the single sentence in the proposed regulatory language that includes

the terms wetland, slough and backwater, Illinois EPA intended merely to provide

a general description and some common examples of locations at which it is not

necessary to achieve the explicit numeric criteria to ensure natural and healthy

aquatic life. These types of locations are outside of the main body of a stream or

outside of the area above the thermocline in waters that seasonally thermally

stratify. *** In using the terms “lake” and “reservoir,” Illinois EPA intends . . .

these terms to represent waters in which thermal stratification occurs regularly on

a seasonal basis and in which a thermocline can be determined by measuring

temperature at equal depth intervals from the surface to the bottom. Tr.5 at 13-14.

The Board notes that the proposed narrative DO standard has two components: one to

protect the ecological function of quiescent and isolated sectors of general use waters, and

another to ensure that offensive conditions do not occur in any general use waters. As to the

former, the Board finds that under certain natural conditions unaffected by deleterious human

activities, dissolved oxygen may periodically decline below numeric standards to concentrations

typically considered acutely harmful to aquatic life. USEPA observed this phenomenon in its

NCD:

Naturally-occurring [DO] concentrations may occasionally fall below target

criteria levels due to a combination of low flow, high temperature, and natural

oxygen demand. Under these circumstances the numerical criteria should be

considered unattainable, but naturally-occurring conditions which fail to meet

criteria should not be interpreted as violations of criteria. Although further

reductions in [DO] may be inadvisable, effects of any reductions should be

compared to natural ambient conditions and not to ideal conditions. Exh. 2

(NCD) at 28.

To address these unavoidable situations, one component of the proposed narrative

standard requires that quiescent and isolated sectors of general use waters, such as wetlands and

waters below the thermocline in lakes, be maintained at sufficient DO concentrations to support

their natural ecological functions and resident aquatic communities. This provision reflects the:

recognition of why we cannot attain and we don’t believe it’s reasonable to expect

to attain the standards we set for the bulk of the general use waters in Illinois.

There are isolated areas where the physical and chemical and biological

circumstances are such that you cannot maintain that standard. Nevertheless, you

must maintain sufficient oxygen that you don’t have other problems develop, like

odors and things of that nature. Tr.4 at 61-62 (quoting Frevert).

The numeric standards for DO proposed today do not apply in these quiescent and

isolated sectors, but rather only in the main body of streams, in the water above the thermocline

of thermally stratified lakes and reservoirs, and in the entire water column of unstratified lakes

and reservoirs. The Board agrees with IEPA that this narrative provision will supplement the

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85

numeric DO standards, helping to ensure that environmentally acceptable conditions are

provided “throughout the full spectrum of General Use waters.” Tr.4 at 25 (quoting Frevert).

The other component of the proposed narrative standard cross-references the existing

Board regulation at Section 302.203 on offensive conditions. The Board finds that this narrative

provision eliminates any potential doubt that even with the new DO standards, general use

waters at all locations must still maintain sufficient DO concentrations to prevent offensive

conditions. Tr.4 at 62. Section 302.203, entitled “Offensive Conditions,” provides:

Waters of the State shall be free from sludge or bottom deposits, floating debris,

visible oil, odor, plant or algal growth, color or turbidity of other than natural

origin. The allowed mixing provisions of Section 302.102 shall not be used to

comply with the provisions of this Section. 35 Ill. Adm. Code 302.203.

After submission of the joint DNR/IEPA proposal, IAWA asked that the Board adopt the

narrative standard and the “thermocline” definition proposed by DNR and IEPA. PC 102 at 1.

There is no opposition in this rulemaking record to these provisions. The Board finds that the

narrative standard proposed by the State agencies is a necessary and appropriate supplement to

the numeric standards. The Board includes the proposed narrative standard and related definition

of “thermocline” in the first-notice proposal.

DISSOLVED OXYGEN SATURATION VERSUS CONCENTRATION

Dr. Murphy’s Proposal to Use Percent Saturation

Dr. Murphy raises the issue of mathematically relating percent saturation and

concentration in mg/L, stating that they are not equivalent measures of the availability of oxygen

to organisms. Dr. Murphy explains while DO is often reported in mg/L concentration, the

percent saturation or oxygen tension should be used to express the availability of oxygen to

organisms. Dr. Murphy suggests that the DO water quality standard be based on oxygen

availability using the percent saturation rather than the concentration. Exh. 19 at 2. According

to Dr. Murphy, the percent saturation is what an organism experiences. Exh. 27 at 3.

Reviewing USEPA’s 1986 NCD for DO (Chapman 1986), Dr. Murphy notes that most of

the reports of DO concentrations in the NCD do not include the temperature of the measurement,

which precludes determining the percent saturation of dissolved oxygen. Exh. 27 at 1; Exh. 31 at

2. Dr. Murphy cites to a reference book on the principles of respiratory physiology by Pierre

Dejours (1981),

Principles of Comparative Respiratory Physiology

. Dr. Murphy states that the

book discusses gas exchange in organisms, including fish and other aquatic organisms. In

chapters relevant to aquatic organisms, Dr. Murphy counted 88 equations that related to gas

exchange or transport in the functioning of organisms. Dr. Murphy emphasizes that in each

equation, the gas was expressed in units of pressure; gas concentration in mg/L was not used.

Exh. 27 at 2.

Dr. Murphy points out the proposed standards and supporting documents are based on

units of mass in mg/L. According to Dr. Murphy, there is a proportionality between pressure

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86

units and mass units, and the proportionality factor differs depending on temperature. Exh. 27 at

3. Dr. Murphy explains that oxygen has a higher solubility in cold water than in warm water,

such that 100 percent oxygen saturation is 14.6 mg/L at 0°C and at 7.5 mg/L at 30°C. Therefore,

Dr. Murphy calculates that waters at 0°C with 7.5 mg/L are 51 percent saturated.

Id

.

Relating oxygen saturation to fish health, Dr. Murphy quotes Davis, John C. (1975),

“Minimal DO Requirements of Aquatic Life with Emphasis on Canadian Species: A Review,”

Canadian Journal of Fisheries and Aquatic Sciences

, 32,2295-2332:

It must be emphasized that . . . fish require both the correct oxygen tension

(pressure) gradient to move O

2

into the blood and sufficient oxygen (per unit

volume of water breathed) to fulfill the requirements of metabolism. Exh. 31 at 3.

Dr. Murphy also refers to recommended DO criteria for the protection of fish populations,

emphasizing that Davis (1975) recommended criteria in units of percent saturation, not mg/L.

Exh. 27 at 3, citing to Davis (1975) at 32,2295-2332.

Dr. Murphy explains the transfer of gases between phases (such as between air and water

across the water surface, or between water and a fish across a gill surface) is driven by the

difference in partial pressure of the two phases. Exh. 31 at 2. The concentration of oxygen

dissolved in the water is a function of the pressure of oxygen in the atmosphere as well as the

temperature and salinity of the water.

Id

. More oxygen, continues Dr. Murphy, is required to

saturate water at 0°C than at 25°C, making oxygen more available to an organism at warmer

temperatures than cooler ones.

Id

. Dr. Murphy calculates that a concentration of 4 mg/L DO

represents 53% saturation at 30°C and 27% saturation at 0°C.

Id

.

Dr. Murphy proposes reevaluating the DO data in the record in terms of percent

saturation and revising the proposed standards. According to Dr. Murphy, to account for oxygen

saturation at differing temperature ranges, the DO standard (in mg/L) could be set higher for the

lower temperatures. Exh. 31 at 3. Dr. Murphy suggests dividing the DNR/IEPA-proposed tiers

into three or more sections, each covering a limited temperature range, and setting separate DO

standards for each temperature range based on the percent saturation. Using the percent

saturation, Dr. Murphy states the corresponding mass of oxygen could be determined and used as

a proxy for a pressure-based standard. Exh. 27 at 4-5, Exh. 31 at 3.

Responses to Dr. Murphy’s Proposal to Use Percent Saturation

As for using saturation to determine DO criteria, IEPA states that the “methodology [is]

substantially different than that used by IEPA and IDNR.” PC 103 at 15. IEPA maintains that

there is “no connection between this recommendation and the needs of the fish found in Illinois

streams.” PC 103 at 15.

MWRDGC states that DO has been expressed as mg/L in water quality standards since

before the Clean Water Act of 1972 and is currently expressed that way throughout the United

States. PC 98 at 1. MWRDGC points to the testimony of Dr. Murphy where he indicates that a

DO saturation level of 47% or greater is protective.

Id

., citing Tr.5 at 51-52. MWRDGC states

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87

that Dr. Murphy did not provide evidence specific to Illinois showing DO saturation during the

August - February period is limiting or harmful to fish, or that conditions become bad for fish

below 47%. According to the MWRDGC, the needs of fish change during this time of year. PC

98 at 1.

MWRDGC also asserts that concentration and percent saturation are proportional so the

standard could be based on either, but that there is no sound theoretical reason for assuming that

the availability of DO to fish is better represented by percent saturation than by concentration.

PC 98 at 2.

At the time of the November 2006 hearing, Louis Kollias was the Director of Research

and Development for MWRDGC. Exh. 41 at 2. He responded to the testimony of Dr. Murphy

concerning percent saturation.

Id

., citing Tr.3 at 185-193, Tr.4 at 170-172. According to

Kollias, USEPA’s NCD noted that a committee of scientists, established by the Research

Advisory Board of the International Joint Commission, reviewed the DO criterion for the Great

Lakes. The committee concluded that a criterion based on dissolved oxygen concentration was

preferable to one based on percent saturation (or oxygen partial pressure). The committee

reasoned the rate of oxygen transfer across fish gills is directly proportional to dissolved oxygen

concentration, and that the total amount of oxygen delivered to the gills is a more specific

limiting factor than is oxygen partial pressure

per se

. Kollias states that USEPA agreed with this

conclusion. Exh. 41 at 2, referring to Exh. (NCD) at 2.

Citing Davis (1975), Kollias reiterates that partial pressure, percent saturation, and

concentration of DO are all interrelated. Kollias continues citing Davis (1975), stating that fish

require both the correct oxygen tension (pressure) gradient to oxygen into the blood and

sufficient oxygen concentration (amount per volume of water breathed) to fulfill the

requirements of metabolism. According to Kollias, the majority of monitoring data and data in

the scientific literature relating to fish are based on DO concentration in mg/L. Exh. 41 at 2.

Kollias adds that DO concentration is easier to measure and control. Kollias states that

controlling DO concentration through supplemental aeration and mechanical means is possible,

but controlling oxygen tension is much more difficult and oxygen saturation can be extremely

variable. Exh. 41 at 2.

Board Findings on Use of Percent Saturation

In the introduction of the NCD, USEPA discusses how DO criteria proposed by various

agencies and researchers have generally reflected two basic schools of thought. Exh. 2 (NCD) at

1. One involved a dynamic approach where the criteria would vary with natural ambient DO

minima or with the DO requirements of fish in terms of percent saturation.

Id

. This is similar to

the approach proposed by Dr. Murphy. The other approach maintained that a single minimum

allowable concentration should adequately protect the diversity of aquatic life.

Id

. The NCD

ultimately supported a two-concentration criteria (a mean concentration and minimum

concentration in mg/L).

Id

. at 2, 34.

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88

The NCD characterizes the two-concentration criteria as a “more simplistic approach”

than dynamic variable criteria expressed as percent saturation. Exh. 2 (NCD) at 1-2. When

trying to apply the more simplistic approach, the NCD states that expressing the criteria as a

percent saturation:

could often result in unnecessarily stringent criteria in the cold months and

potentially unprotective criteria during periods of high ambient temperature or at

high elevations. Oxygen partial pressure is subject to the same temperature

problems as percent saturation.

Id

. at 1.

The “temperature problems” arise because temperature is not one of the specific parameters in

the simpler approaches of the two-concentration national criteria or the similarly crafted IAWA

or DNR/IEPA proposals. Temperature is only indirectly reflected in the seasonal assignments of

differing life stages. The “unnecessarily stringent” or “potentially unprotective” issues arise

because a similarly simple DO criteria (mean and minimum) expressed as a percent saturation

would not reflect the dynamics of an additional parameter for temperature variability. Although

Dr. Murphy proposed a dynamic approach that would involve using three or more temperature

ranges within each of the life stages and tiers and using mg/L as a proxy for percent saturation,

the NCD considers using a criteria in terms of mg/L easier to administer than percent saturation.

Id

.

According to the NCD, the amount of DO available to aquatic organisms is also

expressed more directly in terms of mg/L than percent saturation. Exh. 2 (NCD) at 1. As Dr.

Murphy testified, “[e]verybody uses milligrams per liter because that’s what you’re measuring.”

Tr.3 at 201. Percent saturation must be calculated and requires temperature data and a

proportionality factor. Exh. 27 at 2; PC 83 at 2; Tr.3 at 202. As Kollias of MWRDGC observed,

most DO data from monitoring and in the scientific literature relating to fish are based on mg/L.

Exh. 41 at 2.

As to what a fish “experiences,” Dr. Murphy and Kollias both quote Davis (1975), which

emphasizes that fish require both the correct oxygen tension (pressure) gradient and sufficient

oxygen (per unit of water breathed). Exh. 31 at 3; Exh. 41 at 2. The NCD also references Davis

(1975), and the related conclusions of the committee established by the Research Advisory

Board of the International Joint Commission are summarized in the NCD. Exh. 2 (NCD) at 1-2.

The committee found that “the rate of oxygen transfer across fish gills is directly dependent on

the mean difference in oxygen partial pressure across the gill.”

Id

. at 2. The committee further

found that “the total amount of oxygen delivered to the gills is a more specific limiting factor

than is oxygen partial pressure per se.”

Id.

Although dissolved oxygen concentration, partial pressure, and percent saturation are all

interrelated, the Board finds that relying on a criteria based on concentration in mg/L is the more

direct and practical approach. The Board relies on the findings of the committee set forth in the

NCD as described above. As to the supporting body of scientific evidence, currently most DO

monitoring data and the scientific literature regarding fish are based on mg/L. Additionally, the

two-concentration criteria structure presented in the NCD and followed in the IAWA and

DNR/IEPA proposals represents USEPA’s preferred approach to date.

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PROPOSED 6.5 mg/L DISSOLVED OXYGEN

The one modification to the DNR/IEPA proposal suggested by Environmental Law &

Policy Center, Prairie Rivers Network, and Sierra Club is to include a minimum DO level of 6.5

mg/L when water temperature is 10°C or below. The environmental groups rely on Dr.

Murphy’s testimony to arrive at the 6.5 mg/L DO value to address concerns about oxygen

saturation levels. PC 101 at 7, citing Tr.5 at 52.

Although the environmental groups state that the “practical problems of considering

percentage saturation can be overcome by using technology no more complex than a

thermometer,” they suggest instead using a standard that relies on measurement in mg/L. PC

101 at 7. The environmental groups reason that sufficient DO saturation could be ensured during

periods of cold temperature if the DNR/IEPA proposal were modified to include a minimum DO

level of 6.5 mg/L when water temperature is 10°C or below.

Id

. The environmental groups

estimate the proposed modification would not affect many streams or dischargers because

discharges from sewage treatment plants raise ambient water temperatures in the winter.

Id

.

DNR commented on the original proposal of the environmental groups, made at the

November 2006 hearing, that there be a minimum DO concentration of 6.5 mg/L from December

through March for both Level I and Level II waters under the DNR/IEPA proposal. PC 96 at 11.

DNR recognizes that the proposed addition is based on Dr. Murphy’s testimony, in which he

expressed concern that the revised standard would not ensure sufficient DO for aquatic life

during low temperatures.

Id

. If the Board is going to adopt a minimum DO concentration of 6.5

mg/L, DNR encourages the Board to consider basing the standard “on a temperature basis, when

water temperatures reach 10 degrees centigrade or below, in lieu of the calendar months of

December through March.”

Id

. Of course, the environmental groups modified their proposal

accordingly, as explained above.

The Board notes, however, that according to DNR, it is likely that the physiological

needs of aquatic organisms at low temperatures are lessened because of “lower metabolic rates

during these cold periods.” PC 96 at 11. The Board further notes that, as IEPA observed, no one

in this proceeding had previously suggested that the Illinois’ current DO standard of 6.0 mg/L is

inadequate to protect Illinois aquatic life, “rather that it inadequately addresses the natural

variability of [DO].” PC 103 at 15. Moreover, USEPA’s NCD does not appear to contemplate a

temperature-triggered DO standard.

The Board finds that there is simply not enough evidence in this record to demonstrate

that a 6.5 mg/L DO standard whenever water temperature is 10°C or lower is necessary or

appropriate to supplement the numeric and narrative standards described above for Illinois

general use waters and being proposed for first notice today. The Board invites public comment

on whether other states with conditions similar to Illinois have adopted numeric DO standards

whose applicability is based explicitly on water temperature.

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IMPLEMENTATION CONCERNS

Monitoring and Calculating

When compared to Illinois’ existing DO standard, IAWA states that its proposed standard

would require more extensive DO monitoring and may require using continuous monitors.

Statement at 2. IAWA’s proposal includes language on monitoring. IAWA proposed that the

“mean minimum” DO level “should be based on a data recorder or representative grab samples”

and that the “mean” DO level “should be based on data collected by semi-continuous data

loggers or estimated from the representative daily maxima and minima values.”

Environmental Law & Policy Center, Prairie Rivers Network, and Sierra Club express

concern that implementation procedures for defining averages and providing monitoring have

not been developed in the record. PC 101 at 2, 7. For example, questions remain as to whether

IEPA will develop implementation rules to require continuous monitoring, predawn monitoring,

or monitoring with certain safeguards. The environmental groups state that this might impact

whether water bodies are included in the TMDL list because monitoring that only occurs during

daylight hours would not show that a water body has adequate DO levels at all times.

Id

. at 8.

Lanyon of MWRDGC indicated that the joint DNR/IEPA proposal is unclear if the daily

mean would be calculated based on seven consecutive days or any seven days in the five-month

period. Exh. 25 at 11. Similarly unclear are the calculations for the 7- and 30-day averages,

according to Lanyon.

Id

. at 12. Referring to MWRDGC’s current water quality monitoring

efforts in the Illinois Waterway between Peoria and Lockport, Lanyon notes that MWRDGC

would not have sufficient data to calculate 7- and 30-day averages.

Id

. at 13.

Lanyon comments that the DNR/IEPA-proposed definition of “daily mean” may have

little practical value unless IEPA expands its monitoring program or requires permittees to

conduct more frequent monitoring. Exh. 25 at 13. MWRDGC’s ambient water quality

monitoring program collects samples monthly, which would not be sufficient for calculating a

daily mean or 7- or 30-day averages.

Id

. Kollias of MWRDGC states that the proposed rules

need clarification as to what method should be used to calculate the 7-day daily minimum, 7-day

daily mean, and the 30-day average of daily means, as well as how many sample points must be

maintained. Exh. 41 at 8. Lanyon testified that a “protocol” should:

address both time and space issues, time in terms of how often one samples, what

interval of data is used, whether it’s monthly, daily, hourly, 15 minutes, or in

terms of space as to what segment -- or what point in the reach one should

monitor, should it be the upstream end of the reach, the downstream end of the

reach. Since the State has gone to the extent of dividing up our waterways into

water body segments or assessment units, as they were referred to today, we

should have some clarity as to where in these segments or units we should be

performing the monitoring. Tr.4 at 151.

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Permits

In response to a question about how compliance with the joint-agency proposed DO

standards would be determined, Frevert of IEPA testified:

Compliance determinations will be made by direct measurement of the resource

where the standard applies. Compliance of specific discharges will be based upon

the enforceable discharge limitations contained with each facility’s NPDES

[National Pollutant Discharge Elimination System] permit. [Regarding] stream

assessments performed pursuant to the Clean Water Act [303(d)] requirements,

the Agency is assessing the degree of attainment or support of the aquatic use. To

the extent that the aquatic community shows signs of impairment, DO

measurements will be used to determine whether oxygen stress is a potential

cause or contributor to the observed impairment. Tr.5 at 16-17.

As for point source dischargers located immediately upstream of proposed enhanced DO

segments, IEPA states that it “does not intend to modify its approach to permit issuance.” Exh.

22 at 3. Specifically, according to IEPA:

In most instances authorization of point source discharge containing

deoxygenating material, limits for Biochemical Oxygen Demand are based upon

direct application of technology based treatment limits specified in state effluent

standards, federal secondary treatment requirements for domestic sewage and

federal “categorical” effluent limits for industrial wastewater dischargers. In the

case of lagoon exemptions for smaller facilities there is a provision to relax

technology based requirements if it can be demonstrated that water quality

standards would be attained with the relaxed limits. Should the standards change,

the demonstrations supporting issuance of a lagoon exemption would be

compared to whatever the new standard becomes.

Id

.

Further, IEPA states that it does not routinely establish DO limits in NPDES

permits, unless the discharge is a “substantial or dominant portion of the stream flow below the

point of discharge.” Exh. 22 at 3. In these instances, IEPA notes, the DO water quality standard

will be violated immediately downstream of the discharge point “if the oxygen content of the

discharge itself is substantially below the standard.”

Id

. As a matter of practice, IEPA has:

applied a minimum oxygen content limit for the discharge based upon the need to

meet the stream standard and as a readily available and affordable technology.

IEPA anticipated few if any permitted discharges in the state where the

dominance of discharge relative to the base stream flow will be changed by any

action by the Board. Should the standard change, particularly through inclusion

of a seven day average, permit limits may be adjusted to coincide with the

standard average, but the need to assure an oxygenated discharge will not change.

Id

.

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Although not before the Board at this time, Environmental Law & Policy Center, Prairie

Rivers Network, and Sierra Club raise the issue of permit limits for deoxygenating wastes. PC

101 at 2. Frevert testified that the DO water quality standard was only rarely, if ever, used to set

permit limits because the Agency uses instead the deoxygenating waste rule to establish permit

limits.

Id

. at 10. The environmental groups are concerned about low DO levels in waters that

receive high levels of sewerage discharges because the “tightest” discharge limit under 35 Ill.

Adm. Code 304.120 is 10 mg/L CBOD

5

.

Id

. The environmental groups mention that other states

use models to determine the limits for deoxygenating wastes, and suggest Illinois do the same.

Id

. at 11.

Board Findings on Implementation Concerns

The Board appreciates the concerns of the participants over how the new DO standards

will be implemented, as well as IEPA’s perspective on the permitting process. At one point in

this proceeding, back on July 21, 2004, Environmental Law & Policy Center, Prairie Rivers

Network, and Sierra Club filed a “motion to suspend consideration of proposed amendments to

the dissolved oxygen standard pending development of draft implementation rules.” Ultimately,

these environmental groups withdrew their motion.

The Board notes that, on occasion, draft IEPA“implementation procedures” have been

made part of a Board rulemaking docket setting a water quality standard.

See

Revision to

Antidegradation Rules: 35 Ill. Adm. Code 302.105, 303.205, 303.206, and 102.800-102.830,

R01-13. Before withdrawing their motion to suspend the DO rulemaking, Environmental Law &

Policy Center, Prairie Rivers Network, and Sierra Club cited an ammonia rulemaking, Triennial

Water Quality Review: Amendments to 35 Ill. Adm. Code 302.202, 302.212, 302.213, 304.122

and 304.301 (Ammonia Nitrogen), R94-1(B), as an example of a proceeding in which IEPA

should have filed draft IEPA implementation procedures to avoid subsequent confusion with

permitting. Mot. to Suspend at 4. The Board agrees with IEPA, however, that the ammonia

standard itself, which varies with the temperature and pH of the receiving stream, necessitated a

permitting process for ammonia discharges that was “unusual and uncomparably complicated.”

IEPA Resp. to Mot. to Suspend at 4 (Aug. 6, 2004).

The Board further agrees with IEPA that developing or adopting IEPA implementation

“rules” is not necessarily a prerequisite to USEPA approval of these DO water quality standards.

IEPA Resp. to Mot. to Suspend at 4-5. Moreover, Frevert of IEPA testified that he does not

anticipate IEPA adopting any regulations on DO sampling:

I don’t anticipate any agency rules on that. We certainly establish our own field

practices and field methodology, and we may identify some guidelines there for

applications in certain types of circumstances, but that -- again, that’s our field

methods and manuals. That’s not a regulation or an agency rule. Tr.5 at 253.

The new DO standards will now include 7- and 30-day averages to help ensure that

aquatic organisms are not subject to chronically low DO. This critical enhancement to Illinois’

current standard alone is expected to lead to additional monitoring beyond that presently

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performed to determine compliance with 6.0 mg/L during 16 hours of any 24-hour period and

5.0 mg/L at any time. As discussed below, the proposed first-notice amendments will describe

how to assess attainment of the DO mean and minimum values. The DO data needed to make

these assessments will no doubt inform the eventual monitoring process. As IEPA pointed out

early in this rulemaking, the temporal detail and measurement techniques necessary to determine

compliance with the DO standard are “an inherent part of the standard itself, not separate

implementation procedures.” IEPA Resp. to Mot. to Suspend at 3 (Aug. 6, 2004).

On carrying out a measuring program to determine attainment of the DO standard,

Frevert testified:

It is their responsibility to assure that the way they design their monitoring system

and the way they collect their data, it is truly representative, not misrepresentative

of the normal variation. You can’t go out and get three samples at nine at night,

ten o’clock at night and eleven o’clock at night and pretend they represent the full

24-hour period. And I’m not trying to specify how many samples is the minimum

to do it correctly. I think that would be a difficult or impossible task, but you

must -- if you’re collecting data and you’re using it to draw conclusions or make

assertions about compliance with this standard, it’s your responsibility to look at

the representativeness of your monitoring scheme and its statistical reliability.

Tr.4 at 75-76.

IEPA has stated in this record that DO is not routinely included as an NPDES permit

effluent concentration and that even for dischargers located immediately upstream of stream

segments selected for enhanced DO protection, IEPA does not plan to modify its permit issuance

approach. According to Frevert:

The DO standard that we’ve selected for any particular stream, whether it be tier

one or tier two, is based on our understanding of the relative sensitivity of the

biological community that we believe is there. That in and of itself is not going

to have much, if any, impact at all on permit limitations, so we would do a

normal permitting. If indeed the stream is impaired, whether it be in a level one

or level two classification, and a point source is a significant contributing factor

to it, I’m not sure the answer to that is immediately go and try to tweak the

permit. It’s try to figure out what’s going on and to what extent that treatment

facility is really not adequately controlling their waste, and we’re not going to

know that, and I don’t believe whether the stream falls in tier one or tier two is

going to make any difference in the way we treat that situation. Tr.4 at 122-23;

see also

Tr.5 at 254-56 (less than 1% of Illinois NPDES discharge permits have

conditions requiring in-stream monitoring to assess DO attainment; the vast

majority of the permits have discharge limits of 10 or 20 mg/L CBOD

5

set under

the deoxygenating waste (35 Ill. Adm. Code 304.120)).

Having carefully reviewed the record and prior relevant rulemaking precedent, the Board

is not convinced that any monitoring or permitting requirements for the new DO standards need

to be a part of this docket. This docket has appropriately developed to the point where the Board

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can propose what the dissolved oxygen condition of Illinois general use waters should be. That

task of the Board’s is “fundamentally different [from] . . . day-to-day implementation and

management and monitoring and enforcement decisions.” Tr.1 at 142-43 (quoting Frevert). The

Board finds that the focus of this proceeding should remain on the water quality standards

themselves, the adoption of which should not be delayed.

The Board finds that subsection (d) of the DNR/IEPA-proposed Section 302.206 provides

a detailed account of how to assess attainment of daily mean and minimum DO values. For

example, the “daily mean” is described as “the arithmetic mean of dissolved oxygen values

measured in a single 24-hour calendar day,” while the “daily minimum” is described as “the

minimum dissolved oxygen value as measured in a single 24-hour calendar day.” By way of

illustration and for context, the proposed numeric DO standards during August through February

(

i.e.

, non-early life stages) for most general use waters would be 3.5 mg/L “at any time,” 4.0

mg/L as a “daily minimum averaged over 7 days,” (

i.e.

, the 7-day mean minimum), and 5.5 mg/L

as a “daily mean averaged over 30 days” (

i.e.

, the 30-day mean). The proposed DO numeric

standard during March through July (

i.e.

, early life stages) for most general use waters would be

6.0 mg/L as a “daily mean averaged over 7 days” (

i.e.

, the 7-day mean).

The Board agrees, however, with MWRDGC and the environmental groups that

subsection (d) could benefit from specific language on how to assess attainment of the 7-day

mean minimum, the 7-day mean, and the 30-day mean. The joint proposal’s approach of

referring to the daily mean or minimum “averaged over [7 or 30] days” is potentially subject to

conflicting interpretation. To address this concern, the Board has added language adapted from

the joint DNR/IEPA TSD on determining the 7- and 30-day values. Set forth in subsections

(d)(5)-(7), the Board proposes the following for first notice:

1.

The 7-day mean minimum is “the arithmetic mean of daily minimum dissolved

oxygen values from the current and previous 6 calendar days.”

2.

The 7-day mean is “the arithmetic mean of daily mean dissolved oxygen values

from the current and previous 6 calendar days.”

3.

The 30-day mean is “the arithmetic mean of daily mean dissolved oxygen values

from the current and previous 29 calendar days.”

TECHNICAL FEASIBILITY AND ECONOMIC REASONABLENESS

Lanyon of MWRDGC commented on the Use Attainability Analysis (UAA) being

conducted by IEPA for the Chicago Area Waterways (CAWs) and the Lower Des Plaines River

(LDPR). MWRDGC is a principal participant in the UAA. The UAA, Lanyon explains,

includes approximately 90 miles of mostly secondary contact and indigenous aquatic life waters

(to which these proposed DO standards would not apply), but also some general use waters. The

UAA waters are impacted by combined sewer and stormwater overflows containing bacterial

contamination and oxygen-demanding substances. Exh. 25 at 3-4; Exh. 40 at 2-3; Tr.4 at 158-

59.

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These UAA locations, according to Lanyon, meet the water quality standards most of the

time, except for bacteria and DO. Lanyon attributes the lack of compliance with the current DO

standard to the combined sewer and stormwater overflows, runoff from nonpoint areas, warm

water temperatures, and low velocities in the CAWs. Exh. 25 at 3-4; Exh. 40 at 2-3. Lanyon

attributes DO compliance difficulties in the CAWs to the oxygen demanding substances in the

water reclamation plant effluents, which account for approximately 70% of the annual flow

leaving the CAWs at Lockport. Exh. 40 at 3.

For these reasons, MWRDGC finds it necessary to provide supplemental aeration in

waterways downstream of effluent outfalls to meet the applicable standard. Exh. 25 at 4; Exh.

40 at 4. MWRDGC is currently investigating the engineering feasibility and cost of additional

supplemental aeration facilities to achieve DO concentrations of 4.0, 5.0, and 6.0 mg/L in the

CAWs. Exh. 25 at 8. Preliminary results indicate such costs would probably exceed $100

million.

Id

. Even under the DNR/IEPA proposal, the urban-impacted streams (Des Plaines,

Little Calumet, North Branch, and Salt Creek Rivers identified in Exh. 25, Att. 4.) do not all fare

well by Lanyon’s estimation. Exh. 25 at 14.

As part of the CAWs UAA Study, Lanyon states that MWRDGC has evaluated feasible

technologies to address the DO deficiencies during warm weather, which run from $200 to $360

million on a present worth basis. Exh. 40 at 3. Wet weather-related DO deficiencies will be

addressed by the MWRDGC’s Tunnel and Reservoir Plan (TARP), expected to be completed in

2019.

Id

. at 2-3.

Lanyon addressed the variability of DO throughout the day in the Chicago Waterway

System (CWS), the waterways that receive treated effluents from the Calumet, Lemont, North

Side, and Stickney Water Reclamation Plants. Exh. 25 at 4. Variation of DO throughout the day

due to photosynthetic activity is slight in channel reaches with continuous flow, and Lanyon

attributes this to turbidity preventing the penetration of light. In reaches where there is little or

no flow, diurnal variation can be as much as 5 mg/L with a minimum DO concentration of zero.

Id

. at 5.

To determine how well the CAWs would comply with the proposed DNR/IEPA

standards, Kollias of MWRDGC summarized DO measurements from MWRDGC’s Continuous

Dissolved Oxygen Monitoring (CDOM) Program. For the August 2005 through February 2006

period, eight of twelve shallow water CDOM locations were 100% compliant, as were five of

twenty deep-draft locations. For the March 2006 through July 2006 period, two of twelve

shallow water CDOM locations were 100% compliant, as was one of the twenty deep-draft

locations. Exh. 41 at 6-7. Kollias asserts that this analysis gives insight into the impact of the

joint DNR/IEPA proposal.

Id

. at 8-9.

Lanyon believes that of all the monitoring locations in the CAWs, only one location, the

Chicago River at Clark Street, is expected to be able to meet the DNR/IEPA-proposed standard.

Exh. 40 at 4. Lanyon argues that any proposal must carry “a reasonable chance that compliance

will occur.” Exh. 25 at 15. Lanyon recommends, for urban-impacted and CSO-impacted

streams, a “waiver” provision be created to allow time to study the affordability and feasibility of

compliance alternatives.

Id

.; Exh. 41 at 9. Lanyon also suggests a “separate wet weather

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96

standard” that would apply following stormwater runoff, allowing reduced DO levels for a

limited time period. Exh. 25 at 15; Exh. 41 at 9.

To meet the DO standards that result from the UAA Studies, Lanyon indicates that

MWRDGC is planning to add supplemental aeration facilities to its capital improvement

program. Lanyon explains that when a proposed rulemaking for the CAWs comes before the

Board in the future, it will include some other water quality standard than is being proposed by

either the IAWA or DNR/IEPA. Exh. 40 at 4-5.

The Board appreciates the MWRDGC’s insights into the UAA and its comments on the

dissolved oxygen issues in the CAWs, LDPR, and CWS. A new DO standard has the potential

to primarily affect wastewater dischargers (

e.g.

, POTWs, industrial dischargers, and agricultural

point and nonpoint sources) that discharge oxygen-depleting substances, including BOD and

nutrients. Tr.4 at 80-84; Statement at 2.

Section 27(a) of the Act directs the Board to take into account the “technical feasibility

and economic reasonableness of measuring or reducing the particular type of pollution” when

conducting a substantive rulemaking. 415 ILCS 5/27(a) (2006). The new DO standard likely

will indirectly impact technical and economic issues for particular pollutants in discharges.

Section 27(b) of the Act requires the Board to determine whether a proposed substantive

regulation “has any adverse economic impact on the people of the State of Illinois.” 415 ILCS

5/27(b) (2006). The Board finds that the difficulties and costs described by MWRDGC,

however, would not be caused by this rulemaking.

There is no dispute in this record that there are Illinois streams not meeting Illinois’

current DO standard, or that both the IAWA proposal and DNR/IEPA proposal would “result in

some significant (but smaller) number of exceedances [violations].” PC 103 at 14. As IEPA

notes:

In nearly every instance, this rulemaking is expected to be less restrictive than the

current [DO] standard and therefore less likely to yield exceedances (violations)

of no environmental significance. PC 103 at 11;

see also

Tr.4 at 161 (Lanyon

conceded on cross-examination that neither IAWA’s nor DNR/IEPA’s proposal

“would impose a stricter DO standard than we have on the books today”).

IEPA goes further, maintaining that because the DNR/IEPA-proposed DO standards more

accurately reflect aquatic community needs, the joint-agency proposal “will actually be

economically beneficial by more accurately focusing environmental management resources” on

waters “in need.”

Id

. The Board agrees and finds that the amendments proposed for first notice

will not have an adverse impact on the People of the State of Illinois.

Moreover, as discussed above, the Board does not establish an ambient water quality

standard for dissolved oxygen based on whether Illinois waters presently comply with the

standard. The Board’s primary task in this rulemaking is to establish the “minimum permissible

concentrations of dissolved oxygen” that will protect aquatic organisms in general use waters

based on the scientific evidence. 415 ILCS 5/13(a)(1) (2006);

see also

PC 103 at 12. In doing

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so, the Board fulfills its responsibility under the federal Clean Water Act to, in IEPA’s words,

“update outdated standards to reflect the current science.”

Id

. That said, this record’s evidence

indicates that even for sites on or near the approximately 8% of general use stream miles

proposed for enhanced DO protection, 94% of the grab data demonstrated compliance with the

joint proposal’s acute minima standard. Exh. 22 at 2.

Finally, the Board declines to incorporate into the rule the suggestions of MWRDGC for

a “waiver provision for urban impacted streams to study technology for compliance” and a

“separate wet weather standard following storm water runoff.” Tr.5 at 230. As discussed above,

the Act already provides several ways to seek either temporary or permanent site-specific relief

from rules of general applicability, in the form of petitions for variances, adjusted standards, and

site-specific rules. These mechanisms allow for case-by-case demonstrations before the Board

based on factors such as compliance with the general rule imposing an “arbitrary and

unreasonable hardship” (415 ILCS 5/35(a) (2006)), “factors

relating to that petitioner are

substantially and significantly different from the factors relied upon by the Board in adopting the

general regulation” (415

ILCS 5/28.1(c)(1) (2006)), and the factors of “technical feasibility and

economic reasonableness” (415 ILCS 5/27(a) (2006)).

CONCLUSION

Illinois’ current general use water quality standard for dissolved oxygen, adopted in 1972,

is outdated and too simplistic to account for the natural variability of waters and their aquatic

communities across this State. The DO standard proposed today for first notice is consistent

with USEPA’s NCD as adapted to Illinois waters and reflects the current science. By allowing

both public and private resources to be concentrated on general use waters that are truly impaired

by low DO levels, the proposal promises to significantly and economically enhance the

protection of Illinois aquatic life.

The Board is adopting the essential elements of IAWA’s proposal, but with critical

additions proposed by DNR and IEPA. The IAWA proposal of a two-season DO standard with

averaging and DO values consistent with the NCD “warmwater” criteria is a major step toward

modernizing the Illinois standard, but it does not go far enough. It is true that

most

of Illinois’s

aquatic organisms can be characterized as having the DO-sensitivity of “warmwater” organisms

and that

most

spawning is completed in the spring. As this record shows, however, IAWA’s

proposal does not adequately address the fact that there are significant “intermediate” organisms

and “late spring and summer spawners” in Illinois. The Board accordingly is proposing that

designated stream segments (approximately 8% of Illinois’ 71,394 general use stream miles)

have enhanced DO standards based on the presence of meaningful amounts of DO-sensitive

organisms and that the month of July be included in the sensitive “early life stages” timeframe

(

i.e.

, March through July).

The record demonstrates that these additional protections over and

above the IAWA proposal are necessary to fully protect Illinois aquatic life.

The Board agrees with Joel Cross, Acting Manager of DNR’s Watershed Protection

Section, that this proposal is not a “lowering of dissolved oxygen standards within some waters

during certain times of the year, but rather [a] focusing [of] needed protection for most sensitive

types and life stages of aquatic life where required.” Tr.4 at 46. The first-notice proposal

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provides enhanced DO protection when and where it is most needed. Further, the narrative

standard proposed today ensures that the full range of general use waters in Illinois is protected

against low DO. As stated by the Illinois Chapter of the American Fisheries Society, today’s

proposal provides a “flexible standard which affords full protection of Illinois’ aquatic life

without unduly burdening the regulated community with a rigid, antiquated standard.” PC 100 at

2.

The Board also agrees with IEPA that fully restructuring Illinois’ water quality standards

based on a tiered-use classification system will take years. The information in this record has

yielded a greatly improved DO standard. Adopting that standard should not be delayed. As

suggested early in this proceeding by Toby Frevert, IEPA’s Manager of the Division of Water

Pollution Control, we will probably never reach a “perfect understanding of dissolved oxygen to

have a perfect standard,” but that should not deter improving upon the current standard when the

evidence allows. Exh. 14 at 3. The evidence in this record so allows. Moreover, Section

303(c)(1) of the federal Clean Water Act (33 U.S.C. 1313(c)(1)) requires states to undergo

periodic and continuing reviews and updates of their water quality standards. The Board has

every expectation that progress toward some form of tiered-use system will continue and that

when adequately developed, a rulemaking proposal will be filed with the Board.

Additionally, the Board recognizes that after implementation of the final DO standard

adopted in this rulemaking, further study may reveal that regulatory relief is warranted for

specific stream stretches. The Act has mechanisms already in place, such as adjusted standards,

that allow for case-by-case, site-specific relief when the necessary demonstrations are made

before the Board.

The Board thanks all of those who have participated in this proceeding and encourages

their continued participation. The rulemaking record had benefited greatly from the active

participation of many individuals and organizations, including Environmental Law & Policy

Center, Prairie Rivers Network, Sierra Club, MWRDGC, and the Office of Lieutenant Governor

Pat Quinn. The Board expresses deep gratitude to IAWA, DNR, and IEPA for their especially

thorough contributions to this record. IAWA was of course under no legal obligation to initiate

this proceeding, but having done so, it has been instrumental in updating the State’s DO standard

for the first time in some 35 years. DNR and IEPA drew upon their vast collective experience

with Illinois waters in what has been an exceptional cooperative effort between the two State

agencies.

For first-notice publication in the

Illinois Register

and as described in this opinion, the

Board is proposing amendments to Sections 302.100 and 302.206 and proposing a new

Appendix D to Part 302.

The Board will accept written public comment on its first-notice

proposal for 45 days after publication in the

Illinois Register

.

ORDER

The Board directs the Clerk to file the following proposed amendments with the Office of

the Secretary of State for publication of first notice in the

Illinois Register

. Proposed additions to

Part 302 are underlined and proposed deletions appear stricken.

---

99

TITLE 35: ENVIRONMENTAL PROTECTION

SUBTITLE C: WATER POLLUTION

CHAPTER I: POLLUTION CONTROL BOARD

PART 302

WATER QUALITY STANDARDS

SUBPART A: GENERAL WATER QUALITY PROVISIONS

Section

302.100

Definitions

302.101

Scope and Applicability

302.102

Allowed Mixing, Mixing Zones and ZIDs

302.103

Stream Flows

302.104

Main River Temperatures

302.105

Antidegradation

SUBPART B: GENERAL USE WATER QUALITY STANDARDS

Section

302.201

Scope and Applicability

302.202

Purpose

302.203

Offensive Conditions

302.204

pH

302.205

Phosphorus

302.206

Dissolved Oxygen

302.207

Radioactivity

302.208

Numeric Standards for Chemical Constituents

302.209

Fecal Coliform

302.210

Other Toxic Substances

302.211

Temperature

302.212

Total Ammonia Nitrogen

302.213

Effluent Modified Waters (Ammonia)(Repealed)

SUBPART C: PUBLIC AND FOOD PROCESSING WATER SUPPLY STANDARDS

Section

302.301

Scope and Applicability

302.302

Algicide Permits

302.303

Finished Water Standards

302.304

Chemical Constituents

302.305

Other Contaminants

302.306

Fecal Coliform

302.207

Radium 226 and 228

---

100

SUBPART D: SECONDARY CONTACT AND INDIGENOUS AQUATIC LIFE

STANDARDS

Section

302.401

Scope and Applicability

302.402

Purpose

302.403

Unnatural Sludge

302.404

pH

302.405

Dissolved Oxygen

302.406

Fecal Coliform (Repealed)

302.407

Chemical Constituents

302.408

Temperature

302.409

Cyanide

302.410

Substances Toxic to Aquatic Life

SUBPART E: LAKE MICHIGAN BASIN WATER QUALITY STANDARDS

Section

302.501

Scope, Applicability, and Definitions

302.502

Dissolved Oxygen

302.503

pH

302.504

Chemical Constituents

302.505

Fecal Coliform

302.506

Temperature

302.507

Thermal Standards for Existing Sources on January 1, 1971

302.508

Thermal Standards for Sources Under Construction But Not In Operation on

January 1, 1971

302.509

Other Sources

302.510

Incorporations by Reference

302.515

Offensive Conditions

302.520

Regulation and Designation of Bioaccumulative Chemicals of Concern (BCCs)

302.521

Supplemental Antidegradation Provisions for Bioaccumulative Chemicals of

Concern (BCCs)

302.525

Radioactivity

302.530

Supplemental Mixing Provisions for Bioaccumulative Chemicals of Concern

(BCCs)

302.535

Ammonia Nitrogen

302.540

Other Toxic Substances

302.545

Data Requirements

302.550

Analytical Testing

302.553

Determining the Lake Michigan Aquatic Toxicity Criteria or Values - General

Procedures

302.555

Determining the Tier I Lake Michigan Acute Aquatic Toxicity Criterion

(LMAATC): Independent of Water Chemistry

302.560

Determining the Tier I Lake Michigan Basin Acute Aquatic Life Toxicity

Criterion (LMAATC): Dependent on Water Chemistry

---

101

302.563

Determining the Tier II Lake Michigan Basin Acute Aquatic Life Toxicity Value

(LMAATV)

302.565

Determining the Lake Michigan Basin Chronic Aquatic Life Toxicity Criterion

(LMCATC) or the Lake Michigan Basin Chronic Aquatic Life Toxicity Value

(LMCATV)

302.570

Procedures for Deriving Bioaccumulation Factors for the Lake Michigan Basin

302.575

Procedures for Deriving Tier I Water Quality Criteria and Values in the Lake

Michigan Basin to Protect Wildlife

302.580

Procedures for Deriving Water Quality Criteria and Values in the Lake Michigan

Basin to Protect Human Health – General

302.585

Procedures for Determining the Lake Michigan Basin Human Health Threshold

Criterion (LMHHTC) and the Lake Michigan Basin Human Health Threshold

Value (LMHHTV)

302.590

Procedures for Determining the Lake Michigan Basin Human Health

Nonthreshold Criterion (LMHHNC) or the Lake Michigan Basin Human Health

Nonthreshold Value (LMHHNV)

302.595

Listing of Bioaccumulative Chemicals of Concern, Derived Criteria and Values

SUBPART F: PROCEDURES FOR DETERMINING WATER QUALITY CRITERIA

Section

302.601

Scope and Applicability

302.603

Definitions

302.604

Mathematical Abbreviations

302.606

Data Requirements

302.612

Determining the Acute Aquatic Toxicity Criterion for an Individual Substance –

General Procedures

302.615

Determining the Acute Aquatic Toxicity Criterion - Toxicity Independent of

Water Chemistry

302.618

Determining the Acute Aquatic Toxicity Criterion - Toxicity Dependent on Water

Chemistry

302.621

Determining the Acute Aquatic Toxicity Criterion - Procedure for Combinations

of Substances

302.627

Determining the Chronic Aquatic Toxicity Criterion for an Individual Substance -

General Procedures

302.630

Determining the Chronic Aquatic Toxicity Criterion - Procedure for

Combinations of Substances

302.633

The Wild and Domestic Animal Protection Criterion

302.642

The Human Threshold Criterion

302.645

Determining the Acceptable Daily Intake

302.648

Determining the Human Threshold Criterion

302.651

The Human Nonthreshold Criterion

302.654

Determining the Risk Associated Intake

302.657

Determining the Human Nonthreshold Criterion

302.658

Stream Flow for Application of Human Nonthreshold Criterion

302.660

Bioconcentration Factor

---

102

302.663

Determination of Bioconcentration Factor

302.666

Utilizing the Bioconcentration Factor

302.669

Listing of Derived Criteria

APPENDIX A

References to Previous Rules

APPENDIX B

Sources of Codified Sections

APPENDIX C

Maximum total ammonia nitrogen concentrations allowable for certain

combinations of pH and temperature

TABLE A

pH-Dependent Values of the AS (Acute Standard)

TABLE B

Temperature and pH-Dependent Values of the CS (Chronic Standard) for

Fish Early Life Stages Absent

TABLE C

Temperature and pH-Dependent Values of the CS (Chronic Standard) for

Fish Early Life Stages Present

APPENDIX D

Section 302.206(d): Stream Segments for Enhanced Dissolved Oxygen

Protection

AUTHORITY: Implementing Section 13 and authorized by Sections 11(b) and 27 of the

Environmental Protection Act [415 ILCS 5/13, 11(b), and 27]

SOURCE: Filed with the Secretary of State January 1, 1978; amended at 2 Ill. Reg. 44, p. 151,

effective November 2, 1978; amended at 3 Ill. Reg. 20, p. 95, effective May 17, 1979; amended

at 3 Ill. Reg. 25, p. 190, effective June 21, 1979; codified at 6 Ill. Reg. 7818; amended at 6 Ill.

Reg. 11161, effective September 7, 1982; amended at 6 Ill. Reg. 13750, effective October 26,

1982; amended at 8 Ill. Reg. 1629, effective January 18, 1984; peremptory amendments at 10 Ill.

Reg. 461, effective December 23, 1985; amended at R87-27 at 12 Ill. Reg. 9911, effective May

27, 1988; amended at R85-29 at 12 Ill. Reg. 12082, effective July 11, 1988; amended in R88-1 at

13 Ill. Reg. 5998, effective April 18, 1989; amended in R88-21(A) at 14 Ill. Reg. 2899, effective

February 13, 1990; amended in R88-21(B) at 14 Ill. Reg. 11974, effective July 9, 1990; amended

in R94-1(A) at 20 Ill. Reg. 7682, effective May 24, 1996; amended in R94-1(B) at 21 Ill. Reg.

370, effective December 23, 1996; expedited correction at 21 Ill. Reg. 6273, effective December

23, 1996; amended in R97-25 at 22 Ill. Reg. 1356, effective December 24, 1997; amended in

R99-8 at 23 Ill. Reg. 11249, effective August 26, 1999; amended in R01-13 at 26 Ill. Reg. 3505,

effective February 22, 2002; amended in R02-19 at 26 Ill. Reg. 16931, effective November 8,

2002; amended in R02-11 at 27 Ill. Reg. 166, effective December 20, 2002; amended in R04-21

at 30 Ill. Reg. 4919, effective March 1, 2006; amended in R04-25 at 31 Ill. Reg. ___________,

effective ______________.

SUBPART A: GENERAL WATER QUALITY PROVISIONS

Section 302.100

Definitions

Unless otherwise specified, the definitions of the Environmental Protection Act (Act) [415 ILCS

5] and 35 Ill. Adm. Code 301 apply to this Part. As used in this Part, each of the following

definitions has the specified meaning.

"Acute Toxicity" means the capacity of any substance or combination of

---

103

substances to cause mortality or other adverse effects in an organism

resulting from a single or short-term exposure to the substance.

"Adverse Effect" means any gross or overt effect on an organism,

including but not limited to reversible histopathological damage, severe

convulsions, irreversible functional impairment and lethality, as well as

any non-overt effect on an organism resulting in functional impairment or

pathological lesions which may affect the performance of the whole

organism, or which reduces an organism's ability to respond to an

additional challenge.

"Chronic Toxicity" means the capacity of any substance or combination of

substances to cause injurious or debilitating effects in an organism which

result from exposure for a time period representing a substantial portion of

the natural life cycle of that organism, including but not limited to the

growth phase, the reproductive phases or such critical portions of the

natural life cycle of that organism.

"Criterion" means the numerical concentration of one or more toxic

substances derived in accordance with the procedures in Subpart F of this

Part which, if not exceeded, would assure compliance with the narrative

toxicity standard of Section 302.210 of this Part.

“Early Life Stages” of fish means the pre-hatch embryonic period, the

post-hatch free embryo or yolk-sac fry, and the larval period, during which

the organism feeds. Juvenile fish, which are anatomically similar to

adults, are not considered an early life stage.

"Hardness" means a water quality parameter or characteristic consisting of

the sum of calcium and magnesium concentrations expressed in terms of

equivalent milligrams per liter as calcium carbonate. Hardness is

measured in accordance with methods specified in 40 CFR 136,

incorporated by reference in 35 Ill. Adm. Code 301.106.

"Mixing Zone" means a portion of the waters of the State identified as a

region within which mixing is allowed pursuant to Section 302.102(d) of

this Part.

“Thermocline” means the plane of maximum rate of decrease of

temperature with respect to depth in a thermally stratified body of water.

"Total Residual Chlorine" or "TRC" means those substances which

include combined and uncombined forms of both chlorine and bromine

and which are expressed, by convention, as an equivalent concentration of

molecular chlorine. TRC is measured in accordance with methods

specified in 40 CFR 136, incorporated by reference in 35 Ill. Adm. Code

---

104

301.106.

"Toxic Substance" means a chemical substance that causes adverse effects

in humans, or in aquatic or terrestrial animal or plant life. Toxic

substances include, but are not limited to, those substances listed in 40

CFR 302.4, incorporated by reference in 35 Ill. Adm. Code 301.106, or

any "chemical substance" as defined by the Illinois Chemical Safety Act

[430 ILCS 45]

"ZID" or "Zone of Initial Dilution" means a portion of a mixing zone,

identified pursuant to Section 302.102(e) of this Part, within which acute

toxicity standards need not be met.

(Source: Amended at 31 Ill. Reg. __________, effective ________________)

SUBPART B: GENERAL USE WATER QUALITY STANDARDS

Section 302.206

Dissolved Oxygen

General use waters must maintain dissolved oxygen concentrations at or above the values

contained in subsections (a), (b) and (c) of this Section. Dissolved oxygen (STORET number

00300) shall not be less than 6.0 mg/L during at least 16 hours of any 24 hour period, nor less

than 5.0 mg/L at any time.

a)

General use waters at all locations must maintain sufficient dissolved

oxygen concentrations to prevent offensive conditions as required in

Section 302.203 of this Part. Quiescent and isolated sectors of General

Use waters including but not limited to wetlands, sloughs, backwaters and

waters below the thermocline in lakes and reservoirs must be maintained

at sufficient dissolved oxygen concentrations to support their natural

ecological functions and resident aquatic communities.

b)

Except in those waters identified in Appendix D of this Part, the dissolved

oxygen concentration in the main body of all streams, in the water above

the thermocline of thermally stratified lakes and reservoirs, and in the

entire water column of unstratified lakes and reservoirs must not be less

than the following:

1)

During the period of March through July,

A)

5.0 mg/L at any time; and

B)

6.0 mg/L as a daily mean averaged over 7 days.

2)

During the period of August through February,

---

105

A)

3.5 mg/L at any time;

B)

4.0 mg/L as a daily minimum averaged over 7 days and;

C)

5.5 mg/L as a daily mean averaged over 30 days.

c)

The dissolved oxygen concentration in all sectors within the main body of

all streams identified in Appendix D of this Part must not be less than:

1)

During the period of March through July,

A)

5.0 mg/L at any time; and

B)

6.25 mg/L as a daily mean averaged over 7 days.

2)

During the period of August through February,

A)

4.0 mg/L at any time;

B)

4.5 mg/L as a daily minimum averaged over 7 days; and

C)

6.0 mg/L as a daily mean averaged over 30 days.

d)

Assessing attainment of dissolved oxygen mean and minimum values.

1)

Daily mean is the arithmetic mean of dissolved oxygen values

measured in a single 24-hour calendar day.

2)

Daily minimum is the minimum dissolved oxygen value as

measured in a single 24-hour calendar day.

3)

The measurements of dissolved oxygen used to determine

attainment or lack of attainment with any of the dissolved oxygen

standards in this Section must assure daily minima and daily means

that represent the true daily minima and daily means.

4)

The dissolved oxygen value used in calculating or determining any

daily mean or daily minimum should not exceed the air-

equilibrated value.

5)

Daily minimum averaged over 7 days is the arithmetic mean of daily

minimum dissolved oxygen values from the current and previous 6

calendar days.

6)

Daily mean averaged over 7 days is the arithmetic mean of daily mean

dissolved oxygen values from the current and previous 6 calendar days.

---

106

7)

Daily mean averaged over 30 days is the arithmetic mean of daily mean

dissolved oxygen values from the current and previous 29 calendar days.

(Source: Amended at 31 Ill. Reg. __________, effective ________________)

---

107

302.Appendix D Section 302.206(d): Stream Segments for Enhanced Dissolved Oxygen Protection

BASIN NAME

Segment Name

Segment No.

End Points

Latitude

Longitude

COUNTY

Illinois

Aux Sable Creek

239

start 41.3982125891033

-88.3307365155966

GRUNDY

end 41.5221610266554

-88.3153074461322

KENDALL

Baker Creek

123

start 41.0993159446094

-87.833779044559

KANKAKEE

end 41.1187483257075

-87.7916507082604

KANKAKEE

Baptist Creek

160

start 40.5172643895406

-90.9781701980636

HANCOCK

end 40.5217773790395

-90.9703232423026

HANCOCK

Barker Creek

170

start 40.4730175690641

-90.3623822544051

FULTON

end 40.4505102531327

-90.423698306895

FULTON

Battle Creek

196

start 41.791467372356

-88.6440656199133

DEKALB

end 41.8454435074814

-88.6580317835588

DEKALB

Big Bureau Creek

209

start 41.2403303426443

-89.3778305139628

BUREAU

end 41.6599418992971

-89.0880711727354

LEE

Big Rock Creek

275

start 41.6325949399571

-88.5379727020413

KENDALL

end 41.7542831812644

-88.5621629654129

KANE

Blackberry Creek

271

start 41.6432480686252

-88.451129393594

KENDALL

end 41.7663693677829

-88.3855968808499

KANE

Boone Creek

284

start 42.3430701828297

-88.2604646456881

MCHENRY

end 42.3116813126792

-88.3284649937798

MCHENRY

Buck Creek

225

start 41.4305449377211

-88.7732713228626

LASALLE

end 41.4508806057478

-88.919966063547

LASALLE

403

start 40.6513984442885

-88.8660496976016

MCLEAN

end 40.6757825960266

-88.8490439132056

MCLEAN

Camp Creek

116

start 41.0119168530464

-89.7317034650143

STARK

end 41.0202988179758

-89.6817209218761

STARK

---

108

BASIN NAME

Segment Name

Segment No.

End Points

Latitude

Longitude

COUNTY

168

start 40.2936155016035

-90.7791785207262

MCDONOUGH

end 40.3985161419285

-90.5089903510732

MCDONOUGH

Camp Run

115

start 41.0119168530464

-89.7317034650143

STARK

end 41.0575944852479

-89.6822685234528

STARK

Cantway Slough

250

start 41.1654521279715

-87.6179423055771

KANKAKEE

end 41.1204910206261

-87.6018847740212

KANKAKEE

Cedar Creek

164

start 40.4187924503946

-91.0119249544251

HANCOCK

end 40.4320989747514

-90.9816512014458

HANCOCK

Central Ditch

17

start 40.2466345144431

-89.8605138200519

MASON

end 40.259146892407

-89.8331744969958

MASON

Clear Creek

70

start 40.2358631766436

-89.1715114085864

LOGAN

end 40.2817523596784

-89.2105606026356

MCLEAN

Coal Creek

173

start 40.6458316286298

-90.2773695191768

FULTON

end 40.6911917975894

-90.0990104026141

FULTON

Collins Run

243

start 41.4219631544372

-88.3508108111242

GRUNDY

end 41.4172036201222

-88.3955434158999

GRUNDY

Conover Branch

184

start 39.8376993452498

-90.1465720267561

MORGAN

end 39.8696939232648

-90.1234898871846

MORGAN

Coon Creek

60

start 40.1076562155273

-89.0130117597621

DEWITT

end 40.1755351290733

-88.8857086715202

DEWITT

Coop Branch

31

end 39.2042878811665

-90.0972130791043

MACOUPIN

end 39.1194481626997

-89.9878509202749

MACOUPIN

Coopers Defeat Creek

114

start 41.1557502062867

-89.748162019475

STARK

end 41.1485959333575

-89.6944246708098

STARK

Copperas Creek

88

start 40.4856512052475

-89.8867983078194

FULTON

end 40.549513691198

-89.9011907117391

FULTON

Court Creek

122

---

109

BASIN NAME

Segment Name

Segment No.

End Points

Latitude

Longitude

COUNTY

start 40.9184191403691

-90.1108008628507

KNOX

end 40.9349919352638

-90.2673514797552

KNOX

Cox Creek

177

start 40.0231674243157

-90.1158780774246

CASS

end 39.9657957063914

-90.0180644049351

CASS

Crane Creek

174

start 40.1328714038267

-89.9709414534257

MENARD

end 40.2466345144431

-89.8605138200519

MASON

Crow Creek

102

start 40.9323207251964

-89.4264477600798

MARSHALL

end 40.9663161180876

-89.2558617294218

MARSHALL

Deer Creek

59

start 40.117679723776

-89.3801215076251

LOGAN

end 40.1915602627115

-89.1582023776838

LOGAN

Dickerson Slough

421

start 40.3597968706068

-88.3225685158141

CHAMPAIGN

end 40.4568389800294

-88.3442742579475

FORD

Drummer Creek

423

start 40.37389931547

-88.3480753423386

CHAMPAIGN

end 40.479101489993

-88.388698487066

FORD

Dry Fork

35

start 39.1989703827155

-89.9609795725648

MACOUPIN

end 39.1445756951412

-89.8876581181152

MACOUPIN

Du Page River

268

start 41.4988385272507

-88.2166248594859

WILL

end 41.7019525201778

-88.1476209409341

WILL

Eagle Creek

392

start 41.1360015419764

-88.8528525904771

LASALLE

end 41.1291172842462

-88.8664977236647

LASALLE

East Aux Sable Creek

240

start 41.5221610266554

-88.3153074461322

KENDALL

end 41.6231669397764

-88.2938779285952

KENDALL

East Branch Big Rock Creek

277

start 41.7542830239271

-88.5621632556731

KANE

end 41.8161922949561

-88.6002917634599

KANE

East Branch Copperas Creek

47

start 40.549514632509

-89.901189903351

FULTON

---

110

BASIN NAME

Segment Name

Segment No.

End Points

Latitude

Longitude

COUNTY

end 40.6583152735498

-89.8516717710553

PEORIA

East Fork La Moine River

167

start 40.3962156185095

-90.9339386121768

HANCOCK

end 40.4506930058171

-90.758703782814

MCDONOUGH

East Fork Mazon River

256

start 41.1872307009926

-88.2731640461448

GRUNDY

end 41.0815161304671

-88.3093601699244

LIVINGSTON

East Fork Spoon River

110

start 41.2158736312898

-89.6870256054763

STARK

end 41.2603216291895

-89.7311074496692

BUREAU

Easterbrook Drain

410

start 40.3687232740908

-88.5787269955356

MCLEAN

end 40.3909243275675

-88.5484031360558

MCLEAN

Exline Slough

252

start 41.1187483257075

-87.7916507082604

KANKAKEE

end 41.3377194296138

-87.674538578544

WILL

Fargo Run

94

start 40.8110626738718

-89.7625906815013

PEORIA

end 40.7936211492847

-89.7147157689809

PEORIA

Ferson Creek

281

start 41.9275380999085

-88.3177738518806

KANE

end 41.9518312998438

-88.3965138071814

KANE

Fitch Creek

131

start 41.0629732421579

-89.9929808862433

KNOX

end 41.1048465021615

-90.0171275726119

KNOX

Forked Creek

265

start 41.312634893655

-88.1518349597477

WILL

end 41.4208599921871

-87.8221168060732

WILL

Forman Creek

129

start 41.0920068762041

-90.1229512077171

KNOX

end 41.061779692349

-90.1373931430424

KNOX

Fourmile Grove Creek

232

start 41.5880621752377

-89.0154533767497

LASALLE

end 41.6281572065102

-89.0480036727754

LEE

Fox Creek

121

start 41.2158736312898

-89.6870256054763

STARK

end 41.2178841576744

-89.6378797955943

BUREAU

Fox River

270

start 41.6177003859476

-88.5558384703467

KENDALL

end 41.7665361019038

-88.3100243828453

KANE

---

111

BASIN NAME

Segment Name

Segment No.

End Points

Latitude

Longitude

COUNTY

Friends Creek

56

start 39.9296881580789

-88.7753341828841

MACON

end 40.0511150621524

-88.756810733868

MACON

Furrer Ditch

175

start 40.259146892407

-89.8331744807195

MASON

end 40.256856262248

-89.8235353908665

MASON

Gooseberry Creek

138

start 41.0815161304671

-88.3093601699244

LIVINGSTON

end 41.0229178273291

-88.3433997610298

LIVINGSTON

181

start 41.2273512263311

-88.3737634512576

GRUNDY

end 41.1567969821084

-88.3954921510714

GRUNDY

Grindstone Creek

169

start 40.2936155016035

-90.7791785207262

MCDONOUGH

end 40.3128991202966

-90.6514786739624

MCDONOUGH

Hall Ditch

176

start 40.214043063866

-89.8947856138658

MASON

end 40.1996396083582

-89.8430392085184

MASON

Hallock Creek

101

start 40.9330251540704

-89.523027406387

PEORIA

end 40.9162496002415

-89.5368879858621

PEORIA

Haw Creek

125

start 40.8575772861862

-90.2335091570553

KNOX

end 40.9174343445877

-90.3387634753254

KNOX

Henline Creek

401

start 40.5867014223785

-88.6971328093932

MCLEAN

end 40.6247936449316

-88.6315733675586

MCLEAN

Henry Creek

100

start 40.932455717876

-89.5256512687818

PEORIA

end 40.9472322228041

-89.5711427004422

PEORIA

Hermon Creek

126

start 40.7818347201379

-90.2738699961108

KNOX

end 40.7628476930817

-90.3372052339614

KNOX

Hickory Creek

244

start 41.5038289458964

-88.0990240076033

WILL

end 41.4935392717868

-87.8108342251738

WILL

Hickory Grove Ditch

87

start 40.4870721779667

-89.7285827911466

TAZEWELL

end 40.4136575635669

-89.7349507058786

MASON

Hickory Run

93

---

112

BASIN NAME

Segment Name

Segment No.

End Points

Latitude

Longitude

COUNTY

start 40.8217198390551

-89.7449749384213

PEORIA

end 40.8581447502391

-89.7622130910013

PEORIA

Hillsbury Slough

416

start 40.3453953438371

-88.3035309970523

CHAMPAIGN

end 40.3928682378873

-88.2265028280313

CHAMPAIGN

Hodges Creek

34

start 39.2630316914552

-90.1858200381692

GREENE

end 39.2801974743086

-90.1528766403572

GREENE

Hurricane Creek

44

start 39.449376470161

-90.5400508230403

GREENE

end 39.4781872332274

-90.4508986197452

GREENE

Illinois River

236

start 41.3255740245957

-88.9910230492306

LASALLE

end 41.3986780470527

-88.2686499362959

GRUNDY

Indian Creek

120

start 40.988610901184

-89.8221496834014

STARK

end 41.2003389912185

-89.9349435285117

HENRY

182

start 39.8785447641605

-90.3782080959549

CASS

end 39.8234731084942

-90.103743390331

MORGAN

224

start 41.7480730242898

-88.8741562924388

DEKALB

end 41.7083887626958

-88.9437996894049

LEE

226

start 41.4400734113231

-88.7627018786422

LASALLE

end 41.7377348577433

-88.8557728844589

DEKALB

396

start 40.7701181840118

-88.4858209632899

LIVINGSTON

end 40.6469799222669

-88.4812665778082

LIVINGSTON

Iroquois River

253

start 41.0739205590002

-87.8152251833303

KANKAKEE

end 40.9614905075375

-87.8149010739444

IROQUOIS

447

start 40.7817769095357

-87.7532807121524

IROQUOIS

end 40.8174648935578

-87.5342555764515

IROQUOIS

Jack Creek

109

start 41.1283656948767

-89.7699479168181

STARK

end 41.150467875432

-89.8374616586589

STARK

Jackson Creek

246

start 41.4325013563553

-88.1725611633353

WILL

end 41.4638503957577

-87.9160301224816

WILL

Joes Creek

33

start 39.2801974743086

-90.1528766403572

GREENE

end 39.3757180969001

-90.0772968234561

MACOUPIN

---

113

BASIN NAME

Segment Name

Segment No.

End Points

Latitude

Longitude

COUNTY

Johnny Run

258

start 41.2826709079541

-88.3633805819326

GRUNDY

end 41.0807507198308

-88.5801638050665

LIVINGSTON

Jordan Creek

266

start 41.3044458242397

-88.1279087273328

WILL

end 41.3077177643453

-88.1188984685001

WILL

Judd Creek

106

start 41.089645284216

-89.1847595119809

MARSHALL

end 41.0429807674449

-89.1339049242164

MARSHALL

Kankakee River

248

start 41.3923135096469

-88.2590124225285

GRUNDY

end 41.1660752568715

-87.526360971907

KANKAKEE

Kickapoo Creek

57

start 39.9932216924528

-88.8083252484687

MACON

end 39.9987405799186

-88.8205170598483

MACON

65

start 40.1286520491088

-89.4532728967436

LOGAN

end 40.4376592310728

-88.8667409562596

MCLEAN

92

start 40.6548826785105

-89.6134608723157

TAZEWELL

end 40.9170471944911

-89.6577393908301

PEORIA

Kings Mill Creek

83

start 40.4558745105979

-89.1642930044364

MCLEAN

end 40.509184986927

-89.0937965002854

MCLEAN

La Harpe Creek

159

start 40.4678428297867

-91.0424167497572

HANCOCK

end 40.5172643895406

-90.9781701980636

HANCOCK

La Moine River

158

start 40.3320849972693

-90.8997234923388

MCDONOUGH

end 40.5923258750258

-91.0177293656635

HANCOCK

Lake Fork

61

start 40.0837107988142

-89.3969397975165

LOGAN

end 39.9367293000733

-89.2343282851812

LOGAN

Langan Creek

254

start 40.9614905075375

-87.8149010739444

IROQUOIS

end 40.9432018898477

-88.0465558527168

IROQUOIS

Lime Creek

214

start 41.4515003790233

-89.5271752648714

BUREAU

end 41.4951141474998

-89.456554884734

BUREAU

Little Indian Creek

183

start 39.8355964564522

-90.1231971747256

MORGAN

---

114

BASIN NAME

Segment Name

Segment No.

End Points

Latitude

Longitude

COUNTY

end 39.8658175367056

-90.0423591294145

MORGAN

227

start 41.5091299863247

-88.7725444056074

LASALLE

end 41.749433980972

-88.8141442269697

DEKALB

Little Kickapoo Creek

67

start 40.3336625070255

-88.9736094275975

MCLEAN

end 40.394785197415

-88.9473142490326

MCLEAN

Little Mackinaw River

82

start 40.4423190352496

-89.4617848276975

TAZEWELL

end 40.4481261917524

-89.4329939054056

TAZEWELL

Little Rock Creek

274

start 41.6345548769785

-88.5384723455853

KENDALL

end 41.7895688619816

-88.6981590581244

DEKALB

Little Sandy Creek

107

start 41.0912632622075

-89.2247552498617

MARSHALL

end 41.125352501365

-89.1758716886846

PUTNAM

Little Senachwine Creek

99

start 40.9533145540839

-89.5292433956921

PEORIA

end 41.0084439145565

-89.5499765139822

MARSHALL

Little Vermilion River

233

start 41.3237602050852

-89.0811945323001

LASALLE

end 41.5760289435671

-89.0829047126545

LASALLE

Lone Tree Creek

418

start 40.3750682121535

-88.3819688457729

CHAMPAIGN

end 40.3145980401842

-88.4738655755984

MCLEAN

Long Creek

163

start 40.4466427913955

-91.0499607552846

HANCOCK

end 40.4297652043359

-91.1507109600489

HANCOCK

Long Point Creek

68

start 40.2755311999445

-89.0786438507327

DEWITT

end 40.2549604211821

-88.9826285651361

DEWITT

394

start 41.038177645276

-88.7908409579793

LIVINGSTON

end 41.0018214714974

-88.8534349418926

LIVINGSTON

Mackinaw River

397

start 40.5796794158534

-89.2813445945626

TAZEWELL

end 40.5649627479232

-88.478822725546

MCLEAN

Macoupin Creek

32

start 39.1989703827155

-89.9609795725648

MACOUPIN

start 39.2121253451487

-90.2312084410337

JERSEY

Madden Creek

413

---

115

BASIN NAME

Segment Name

Segment No.

End Points

Latitude

Longitude

COUNTY

start 40.0943580002069

-88.5400649488702

PIATT

end 40.2109635906658

-88.4943738561926

PIATT

Masters Creek

220

start 41.4976109383336

-89.4125473607076

BUREAU

end 41.5439000049343

-89.421988392756

BUREAU

Masters Fork

217

start 41.4531024225454

-89.4290492805799

BUREAU

end 41.5702310455498

-89.3821188149649

BUREAU

Mazon River

257

start 41.3086768327676

-88.3389845675056

GRUNDY

end 41.1872307009926

-88.2731640461448

GRUNDY

Mendota Creek

234

start 41.5281666288805

-89.1041764154672

LASALLE

end 41.5282367334928

-89.1224368860589

LASALLE

Middle Branch of Copperas Creek

90

start 40.549514632509

-89.901189903351

FULTON

end 40.5980896362772

-89.9368482699851

FULTON

Middle Creek

165

start 40.3957329294144

-90.9741776721721

HANCOCK

end 40.3888894030526

-91.0072502737366

HANCOCK

Mill Creek

494

start 41.8213649020421

-88.3222376599138

KANE

end 41.9231053361497

-88.4419826012614

KANE

Mole Creek

390

start 41.0193910577853

-88.8019375580673

LIVINGSTON

end 40.9109452909954

-88.9263176124884

LIVINGSTON

Morgan Creek

272

start 41.6481172046369

-88.4151168308869

KENDALL

end 41.6530911245692

-88.3631669287476

KENDALL

Mud Creek

449

start 40.637099482441

-87.5885960450541

IROQUOIS

end 40.6100172186722

-87.5261312404789

IROQUOIS

Mud Run

117

start 41.0092425694765

-89.7790957399812

STARK

end 40.9876287937001

-89.6785472090663

STARK

Murray Slough

259

start 41.2428845425989

-88.3615508333781

GRUNDY

end 41.054741775769