APPROPRIATE THERMAL WATER QUALITY STANDARDS

FOR THE LOWER DES PLAINES RIVER

Summary Report

Prepared by Midwest Generation and EA Engineering, Science and Technology, Inc.

Original Issued: January 24, 2003

Revised: October 13,2003

I.

INTRODUCTION

Midwest Generation, with the assistance ofEA Engineering, Science and Technology, Inc., has

prepared this report for inclusion in the record

ofthe current Use Attainability Analysis (UAA)

for the Lower Des Plaines River. Under the federal Clean Water Act regulations, a UAA is

required

in order to determine iffishable and swimmable uses, reflecting the goals of the Clean

Water Act, are not attainable for a particular water body or segment thereof. [See 40 C.F.R.

§

131.100)].

This report evaluates and compares the present physical, chemical and biological characteristics

ofthe Lower Des Plaines River to the current and proposed future thermal regime ofthe

waterway. The results

ofthis evaluation and comparison support the application ofthermal

water quality standards that are biologically appropriate and adequately protective ofthe existing

and potential uses

of this waterway, given the constraints on the system that are permanent or

cannot be mitigated.

A.

UAA Regulatory Overview

A use attainability analysis is defined as:

...a structured scientific assessment ofthe factors affecting the attainment of a use which

may include physical, chemical, biological, and economic factors as described

in

Section 131.10(g). [40 CFR Section 131.3].

A "use attainability analysis" includes six factors that are to be considered in determining

whether the fishable/swimmable goals

ofthe Clean Water Act are attainable for a particular

water body. [40 CFR § 131.1 O(g)]. These six UAA factors are discussed in this report and are

summarized

in Appendix 1. Under the UAA regulation, only one or more ofthese factors must

be satisfied in order to determine that a water body is not capable of attaining the Clean Water

Act's fishable/swimmable goals.

Of particular relevance in this report are the following four

UAA factors (the paragraph numbering is as found in 40 CFR 131.10(g)):

2.

Natural, ephemeral, intermittent or low flow conditions or water levels prevent

the attainment ofthe use, unless these conditions may be compensated for by the

---

discharge of sufficient volume of effluent discharges without violating State water

conservation requirements to enable uses to be met;

3.

Human-caused conditions or sources

of pollution prevent the attainment ofthe

use and cannot be remedied or would cause more environmental damage to correct than

to leave in place;

4.

Dams, diversions, or other types

of hydrologic modifications preclude the

attainment

of use, and it is not feasible to restore the water body to its original condition

or to operate such modification in a way that would result in attainment

ofthe use;

5.

Physical conditions related to the natural features ofthe water body, such as the

lack

of proper substrate, cover, flow, depth, pools, riffles, and the like, unrelated to water

quality, preclude attainment

of aquatic life protection uses.

B.

Application of the UAA Factors to Assess Chemical, Biological and Physical

Characteristics of the Lower Des Plaines River

U.S. EPA has long advocated the concept of independent application when using the assessment

tools available to make use designation decisions:

"Independent application means that

anyone ofthe three types ofassessment

information (i.e. chemistry, toxicity testing results,

and ecological assessment) provides

conclusive evidence

ofnonattainment ofwater quality standards regardless ofthe results

from other types

ofassessment information. Each type ofassessment is sensitive to

different types ofwater quality impact. Although rare, apparent conflicts in the results

from different approaches can occur. These apparent conflicts occur when one

assessment approach detects a problem

to which the other approaches are not sensitive.

This policy establishes that a demonstration

ofwater quality standards nonattainment

using one assessment method does not require confirmation with a second method and

that the failure

ofa second method to corifirm impact does not negate the results ofthe

initial assessment."

(See U.S.EPA, June 19,

1991 Transmittal ofFinal Policy on

Biological Assessments and Criteria).

Therefore, to reliably determine whether or not fishable and swimmable uses are attainable for

the Lower Des Plaines River, the UAA must include consideration

of physical and biological

integrity, not simply chemical water quality. In

EPA's Water Quality Standards Handbook,

Second Edition (1994), the use

ofbiological criteria to support designated aquatic life use

classifications is strongly encouraged.

Approximately 20 years later, the U.S.EPA continues to endorse the use

of biological

assessments and criteria as a very reliable tool in the development

of appropriate water quality

standards:

"Ecological integrity is a combination

ofthese three components: chemical integrity,

physical integrity

and biological integrity. When one or more ofthese components is

2

---

degraded, the health ofthe waterbody will be affected, and in most cases, the aquatic lift

there will reflect that degradation. Aquatic life integrates the cumulative effects of

different stressors such as excess nutrients, toxic chemicals, increased temperature, and

excessive sediment loading. Therefore, bioassessments allow one to measure the

aggregate impact

ofthe stressors. Because biological communities respond to stresses

over time, they provide information that more rapidly-changing water chemistry

measurements

or toxicity tests do not always produce. As such, bioassessment provides a

more reliable assessment

oflong-term biological changes in the condition ofa

waterbody. The central purpose ofassessing biological condition ofaquatic communities

is to determine how well a water body supports aquatic life".

(EPA 822-F-02-006,

Summer, 2002)

The importance

of basing use designations on biological integrity (as the overall integrator of

waterbody conditions) was emphasized at the U.S.EPA sponsored "National Conference on

Tools for Urban Water Resource Management and Protection" in 2000. In particular, the

relationship between the Index ofBiotic Integrity (IBI), an indicator of biological health, and a

qualitative analysis

of overlying stressors in six major metropolitan areas in Ohio were used by

Yoder, Miltner and White, (2000) to suggest that there is a threshold

ofwatershed urbanization

(e.g.>60%) beyond which attainment

ofwarmwater habitat (equivalent to Illinois' General Use)

is unlikely. Similar reliance on biological assessment data and information were also

recognized by an number

of experts in the proceedings ofthe National Symposium on

"Designating Attainable Uses for the Nation'sWaters" held on June 3-4, 2002 in Washington,

D.C. (GLEC, July 2002).

While Illinois does not have an established bioassessment program in place for large rivers, the

draft bioassessment methodology that the Illinois EPA has developed, based on smaller order

streams, can be successfully applied to the Lower Des Plaines River. Further, because ofmore

than 20 years

of biological and habitat monitoring data available on the UAA Reach, there is an

extensive data base to which this draft bioassessment methodology can be applied to make

decisions regarding the appropriate use designations for the Lower Des Plaines River.

Certainly, the chemical water quality

ofthe Lower Des Plaines River has improved over the past

20 years. However, as the U.S. EPA and others have stated, chemical water quality alone does

not dictate the potential

ofthe waterway from an ecological perspective. Because the UAA

analysis by Novotny/Hey

&

Associates focuses primarily on the chemical water quality ofthe

Lower Des Plaines River, the information and supporting data presented in this report will

address the other two key elements

of a UAA--the physical and biological aspects ofthe Lower

Des Plaines River and their overall potential for improvement, in the context

ofthe 6 UAA

factors. This extensive review

ofthe physical and biological characteristics ofthe water body

shows that focusing primarily on the chemical quality

ofthe Lower Des Plaines River does not

provide a reliable basis on which to determine its use potential. The UAA analysis presented in

this report shows that the physical and biological constraints present in the Lower Des Plaines

River make the full fishable/swimmable uses inherent to a General Use classification

unattainable in this water body. Barring further refinements, such as the addition of

subclassifications, to the existing Illinois Use Classification system, the Lower Des Plaines River

is properly classified as a Secondary Contact Use water body.

3

---

II.

BACKGROUND

Much ofthe background information and data contained in this report was drawn from the

comprehensive ecosystem study

ofthe entire Upper Illinois Waterway (UIW) performed by

Commonwealth Edison ("CornEd") in the early to mid-1990's. Development and

implementation

of this study was done under the direction of an ad hoc task force consisting of

representatives from Illinois EPA, U.S. EPA Region 5, Illinois Department of Natural Resources

and the Metropolitan Water Reclamation District

ofGreater Chicago (MWRDGC), as well as

other interested public, private and academic groups. (See UIW Summary at Appendix 2)

Representatives

of Illinois EPA, IDNR and U.S. EPA have recognized the UIW Study as the

most comprehensive, multi-disciplinary effort ever performed on this waterway.

The overriding purpose ofthe comprehensive, multi-year UIW investigation was to better

understand the effects that temperature increases caused by power plants have on aquatic biota

and especially their potential to stimulate or hinder improvement

ofthe waterway.

A majority

ofthe information collected as part ofthe UIW Study is still valid today. The UIW

Study data and findings need to be carefully considered in the UAA for the Lower Des Plaines

River, including any assessment

ofappropriate thermal water quality criteria for the Lower Des

Plaines River, to ensure that the most complete and reliable data available are used to determine

what use(s) are attainable for this water body. Due to their comprehensive length, this report

cannot extensively reference the studies performed as part

ofthe UIW effort, but does provide a

full executive summary in Appendix 2. All UIW documents are publicly available for review

and can be provided upon request. (See listing

ofUIW Study individual reports and content

summaries in Appendix 3).

ill.

mSTORYOFTHEWATERWAY

The 53-mile section ofthe UIW originally studied by CornEd is a mix of artificial and greatly-

modified natural waterways extending Southwest from Chicago to the Kankakee River.

(Figure 1). Early in the history

of Chicago, a plan was conceived to protect the area'sprimary

water supply, Lake Michigan, by constructing three man-made waterways to permanently

reverse the flows

ofthe Chicago and Calumet River systems away from the lake, and divert the

contaminated water downstream where

it could be diluted in the Des Plaines and eventually the

Illinois River. The man-made Chicago Sanitary and Ship Canal, completed in 1907, merges with

the Des Plaines River about 40 miles downstream

of Lake Michigan near Lockport, Illinois.

Diversion water from Lake Michigan increased the navigation capabilities

ofthe system and

provided additional waste dilution. Construction

ofthe Cal-Sag Channel was completed in 1922,

connecting the Calumet and Little Calumet Rivers with the Chicago Sanitary and Ship Canal.

Construction

ofthese man-made waterways was a significant ecological event.

It

provided a

direct link between the Great Lakes Drainage and the Mississippi Drainage.

Reconstruction

ofthe UIW in its present form began in 1919. A new and larger channel was

constructed

in

the Lower Des Plaines River and the upper Illinois River to form a continuous

4

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navigational channel from Lake Michigan to the Mississippi River. This new channel was at

least

nine feet deep and 300 feet wide throughout and greatly increased the barge transport

capabilities

ofthe system. The project included construction of seven major locks and three

dams, including a 40-foot dam

just south of Lockport and a 34-foot dam just south of Joliet at

Brandon Road. A third, 22-foot dam was constructed at Dresden Island, less than two miles

downstream from the confluence

of the Kankakee and Des Plaines Rivers.

In its

UIW Study, CornEd covered the 53-mile reach between the diversion from Lake Michigan

at Chicago and the Dresden Island Lock and Dam. The current

UAA study reach area is a subset

ofthe entire UIW.

It

extends from the Lockport Lock and Dam on the Chicago Sanitary and Ship

Canal (RM 290) down to the I-55 Bridge on the Lower Des Plaines River

(RM 278). This

subset

ofthe UIW is referred to herein as the "UAA Reach".

A.

Power Plants in the UAA Reach

There are two open-cycle, coal-fired power plants that discharge either into or immediately

above the UAA Reach. These plants, formerly owned and operated by CornEd, were sold to

Midwest Generation in December, 1999. They include:

Will County Station

is located in Romeoville, Illinois, near the intersection ofthe

Chicago Sanitary and Ship Canal and 135th Street.

(RM 295.5) The station has a total of

4 units, with a combined capability of 1154 gross megawatts of electricity. (For

reference: 1 megawatt is enough power to service approximately 1000 homes). The first

Will County unit began operations in 1955; the most recent unit came on-line in 1963.

Joliet Stations #9 (Unit 6) and

#29

(Units

7&8) are capable of producing a total of

approximately 1414 megawatts of electricity. The stations are located in Will County,

. approximately one mile southwest

ofthe City of Joliet, Illinois. (RM 285) They are

located on the Lower Des Plaines River

just downstream ofthe Brandon Road Lock and

Dam.

The older Joliet unit began operating in 1959; the two newer units came on-line in

1966. Joliet Station #29 has 24 supplemental cooling towers to assist with heat

dissipation. These towers were installed in 1999 and are used, as needed, to maintain

near and far-field compliance with the existing thermal water quality standards.

5

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Figure 1:

Figure I:

Map

of Upper

Illinois Waterway, Including UAA Reach

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IV.

CURRENT UAA REACH USE DESIGNATION AND THERMAL WATER

QUALITY STANDARDS

A "designated use" is the use specified in state water quality standards for each water body or

segment. In setting use designations, a state is required to protect "existing uses." (40 CFR

§131.1 0 and §131.12). "Existing uses" are defined as "those uses actually attained in the water

body on or after November 18, 1975, whether or not they are included in the water quality

standards." For the UIW, Illinois EPA

is obligated to protect the uses actually attained as of

November 18, 1975 or thereafter. In January, 1974, the Illinois Pollution Control Board (the

"Board") designated the UIW as a "Secondary Contact and Indigenous Aquatic Life" use water

body under the Illinois use classification system (hereinafter referred to as "Secondary Contact").

With little change since its adoption

in 1974, the purpose ofthe Illinois Secondary Contact use

classification is described in 35 Ill. Adm. Code §302.402 as follows:

Secondary contact and indigenous aquatic life standards are intended for those

waters not suited for general use activities but which will be appropriate for all

secondary contact uses and which will be capable

of supporting an indigenous

aquatic life limited only by the physical configuration

ofthe body ofwater,

characteristics and origin

ofthe water and the presence of contaminants in

amounts that do not exceed the water quality standards listed in Subpart D.

The entire UIW from the South Branch

ofthe Chicago River down to the I-55 Bridge has a

designated use

of Secondary Contact and Indigenous Aquatic Life. The narrative and chemical

criteria associated with the Secondary Contact use designation are listed in Table

1. Other

waters in the state (aside from Lake Michigan and Public and Food Processing Water Supply,

which have their own specific limitations) are designated as General Use waters under the

Illinois use classification system.

A. Thermal Water Quality Standards

With regard to thermal water quality limitations, there are significant differences between

Secondary Use and General Use, as summarized below:

1. Secondary Contact

• Temperature shall not exceed 93 OF for more than 5% ofthe time, or 100 OF at any time

(at the edge

ofthe allowable mixing zone defined by Rule 302.102 of lAC, Title 35,

Chapter

1, Subtitle C).

•

Total of approx. 438 allowable excursion hours in any 12-month rolling period

•

100

OF maximum limitation, year-round

10

---

2.

General

Use

(applicable downstream of the I-55 Bridge)

Narrative Criteria:

•

There shall be no abnormal temperature changes that may adversely affect aquatic life

unless caused by natural conditions.

•

The normal daily and seasonal fluctuations which existed before the addition

of heat due

to other than natural causes shall be maintained.

Numeric Criteria:

•

The water temperature at representative locations in the main river shall not exceed the

maximum limits below during more than 1

%

ofthe hours in any 12-month period ending

with any month. Moreover, at no time shall water temperature at such locations exceed

the maximum limits by more than 3

of:

DECEMBER-MARCH: 60 of

APRIL-NOVEMBER: 90 of

•

Total of approx. 87 allowable excursion hours in any 12-month rolling period

•

The maximum temperature rise above natural temperatures shall not exceed 5

of.

The General Use thermal limitations are considerably more stringent than the Secondary Contact

limits, both in numeric criteria and number

of allowable excursion hours. Of equal concern here

is that the General Use thermal standards by their express terms were intended to apply to

"natural" waterways. The narrative General Use thermal standards assume that "natural"

conditions existed in the waterway before the addition

of point source discharges. Hence, the

General Use thermal standards prohibit temperatures from rising more than 5

of above "natural

temperatures" and also require the maintenance

of natural fluctuations in thermal levels in the

waterway that existed before the addition

of "other than natural" causes. The General Use

thermal water quality standards were never intended to apply, and by their terms, cannot be

applied to a waterway like the UAA Reach. The Lower Des Plaines River is not a "natural"

waterway.

It

is a primarily man-made, artificial waterway with physical characteristics ill-suited

to the application

of General Use standards.

It

was constructed and/or altered for the purpose of

protecting the water quality of Lake Michigan and maximizing commercial navigation, with the

help

of a lock and dam system that artificially creates and regulates water levels and flows.

It

does not have a "natural" temperature.

It

has temperatures that are dictated by the man-made

uses for which it was constructed and/or altered.

3. Adjusted Thermal Standard for I-55

In addition to the two thermal limitations outlined above, there is an adjusted thermal

limitation at the I-55 Bridge currently applicable only to Midwest Generation Power Plants.

This adjusted limit was granted by the Illinois Pollution Control Board (IPCB) in Docket

11

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Number AS96-10, based on the results ofthe comprehensive UIW study performed by

CornEd and overseen by the UIW Task Force. (See IPCB Order and Opinion, AS96-10,

dated Oct. 3, 1996). The Adjusted I-55 Thermal Standard includes the following thermal

limits and conditions:

Adjusted I-55 Thermal Standard

January:

February:

March:

April 1-15:

April 16-30:

May 1-15:

May 16-31:

June 1-15:

June 16-30:

July:

August:

September:

October:

November:

December:

60

of

60 of

65 of

73 of

80 of

85 of

90 of

90

OP

91°F

91 of

91 of

90 of

85

°

F

75

° F

65 °

F

The Adjusted I-55 Thermal Standard may be exceeded by no more than 3 ° F during 2% of

the hours in the 12-month period ending December 31, except that at no time shall Midwest

Generation'splants cause the water temperature at the I-55 Bridge to exceed

93 ° F.

• A total

of 175 excursion hours per calendar year are allowed.

The Adjusted I-55 Thermal Standard replaces the General Use Thermal Water QualityStandard

for the Midwest Generation Plants. The Adjusted I-55 Thermal Standard recognizes the

limitations and artificial influences on the thermal conditions

ofthe UAA Reach while

continuing to protect the existing uses

ofthat waterbody.

V.

THE RELATIONSmp BETWEEN THE ADJUSTED THERMAL STANDARD

AT I-55 AND

THE UAA FOR THE LOWER DES PLAINES RIVER

In seeking the thermal adjusted standard from the IPCB in 1996, CornEd was required, in part, to

show that the proposed adjusted standard would not adversely impact or prevent improvements

to the aquatic community within the UAA Reach. In that proceeding before the IPCB, CornEd

presented data for the entire UIW waterway, from Lake Michigan downstream to the Dresden

Island Lock and Dam. The data presented demonstrated that thermal discharges from the power

plants are not the main factor limiting further improvements in the aquatic community in the

entire waterway, including the UAA Reach. There are other physical and biological constraints

that prevent those improvements. These findings from the UIW Study, relied upon previously by

12

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the IPCB in AS96-l 0 adjusted standard proceeding, are equally applicable here in the UAA of

the Lower Des Plaines River.

According to Section 27(a)

ofthe Illinois Environmental Protection Act (the "Act"), the IPCB

was required to take into account the following factors in determining whether to grant the

adjusted thermal standard requested by CornEd:

(a)

the existing physical conditions;

(b)

the character

ofthe area involved, including surrounding land uses;

(c)

zoning classifications;

(d)

nature

ofthe receiving water body, and

(e)

the technical feasibility and economic reasonableness

of measuring or reducing the

particular type

of pollution.

The Illinois EPA also addressed each

ofthese factors in its recommendation filed with the Board

to grant the adjusted standard

in AS96-l0. (AS96-l0 Agency Recommendation, filed August 9,

1996) The IPCB summarized the Agency'srecommendation as follows:

While stating that it was "technically feasible" to reduce the effluent temperature

from the plants to meet the General Use Thermal WQS (at I-55) by the use

of

cooling towers... the Agency provided the opinion that the costs of installing

additional cooling "may not be economically reasonable when compared to the

likelihood

of no

improvement in the aquatic community ofthe

UIW".

(AS96-

10, Opinion and Order at p.7 )--(emphasis added).

After a thorough review

ofthe information presented in the AS96-l0 proceeding, in October,

1996, the Board granted CornEd the requested I-55 adjusted thermal limitations applicable at the

I-55 Bridge

in the Des Plaines River. (General Use thermal water quality standards continue to

apply to the waterway below the I-55 Bridge). In granting CornEd the thermal adjusted standard,

the Board accepted, with the Illinois

EPA'ssupport, the findings ofthe UIW Study. The UIW

Study found that the operation ofthese power plants does not interfere with maintaining a

reasonably balanced indigenous community

of aquatic organisms in the UIW consistent with the

limited physical habitat and history

of chemical contamination that remains in the sediment and

the predominant uses

ofthe waterway, namely barge transport and conveyance of non-point and

treated point source discharges.

In 2000, with Illinois EPA support, the Board again found that the conditions

in the UIW,

including the lack of impact that the adjusted thermal standards would have on the ecosystem of

the receiving waterway, supported the transfer ofthe adjusted thermal limits from CornEd to

Midwest Generation. (AS96-l0 Opinion and Order, March 16, 2000)

The Board concluded that conditions

in the Lower Des Plaines River in 2000 had not changed

appreciably from when the original thermal adjusted standard was granted, based on the 1991-

1995 data presented

in the UIW Study. Today, just a few years later, these significant limiting

factors in the UAA Reach are still present and prevent it from attaining full General Use status.

13

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There have been no significant changes in Midwest Generation'soperation of its power plants

since the AS96-1 0 adjusted thennal standard was granted. No adverse impacts have been

observed on the indigenous fish community during the course

of the plants' operation since

Midwest Generation assumed ownership in late 1999. Annual fisheries monitoring has

demonstrated that the fish community present is consistent with what one would expect for an

impaired waterway. Midwest Generation continues to monitor the fish community in the

system, as well as temperature and dissolved oxygen at the I-55 Bridge, on a regular basis.

Results

of these studies are submitted to Illinois EPA and other regulatory/environmental groups

on an annual basis. The more recent monitoring results continue to show no appreciable changes

from the 1991-1995 data on which the IPCB granted the thennal adjusted standard.

VI.

CURRENT THERMAL COMPLIANCE STATUS

All thermal discharges from Midwest Generation'spower plants continue to meet the near-field

Secondary Contact standards at the edge ofthe allowed mixing zone, as well as the far-field

adjusted thermal standard at the I-55 bridge. Compliance is maintained through continuous real-

time monitoring, as well as the use of customized thenno-hydrodynamic modeling to adjust

station operations, when warranted, to meet both near and far-field thennal limitations.

VII.

PHYSICALIHYDRAULIC/CHEMICAL NATURE OF THE SYSTEM

The upper two-thirds of the UIW can best be characterized as a slow-moving, relatively unifonn

canal with little or no natural shoreline. The bottom one third is, in essence, a series of

impoundments separated by locks and dams. The hydrology ofthe entire system is complex,

owing to the diverse mixture ofwater sources and their inherent flow variabilities. The flow rate

in the system is unstable, especially in close proximity to the Locks and Dams, and is largely

controlled by flows regulated by the locks and dams, in response to navigational needs, as well

as upstream run-off events. (MWRD, 1992)

The inputs from all water sources vary seasonally, although the system

is dominated by

wastewater treatment plant discharges year-round (Dick Lanyon, MWRD, personal

communication). Currently, summer discretionary diversions from Lake Michigan account for

less than 50% ofthe overall flow. Moreover, as the discretionary diversion from Lake Michigan

into the Ship Canal incrementally decreases as more lake water is used for domestic purposes,

the system will eventually be dominated solely by wastewater treatment plant (WWTP) flows

and non-point source run-offyear-round, without the benefit of any dilution water from Lake

Michigan.

A.

Brief Description of the Pools Comprising the Upper Illinois Waterway

Lockport Pool (Not part ofthe UAA Reach): 34 mile reach. Narrow, dredged waterway with

borders comprised of vertical rock, pilings or rip-rap. Depths vary from 16 to 26 feet.

Brandon Pool: 5 mile reach. Extends for five miles from the Lockport Lock and Dam to the

Brandon Road Lock and Dam. The Des Plaines River enters the Brandon Pool just downstream

14

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ofthe Lockport Lock and Dam (RM 290) at which point the waterway changes from a narrow

man-made channel to a wider canal with an average depth

of20 feet and variable width.

Dresden Pool:

15 mile reach. Extends from the Brandon Road Lock and Dam down to the

Dresden Island Lock and Dam. Main channel depths vary from

15 to 20 feet. The Dresden Pool

has less artificial shoreline than the other two navigational pools. In addition, it has limited off-

channel backwater and slough areas which are largely absent in the upstream reaches. Dresden

Pool also has several minor tributaries, including the DuPage River, Hickory Creek, Jackson

Creek and Grant Creek.

Both the Brandon Pool and upper portion

ofthe Dresden Pool are being evaluated to determine if

it is appropriate to change their current use designation. Lockport, Brandon and Upper Dresden

Pool waters are currently designated as Secondary Contact waterways. (See Table

1)

B.

Effects of Artificial Flow Control and Barge Traffic

From the information presented to the UAA Task Force, Hey and Associates' cursory review of

selected data and conclusions regarding the lack of impact by barge traffic on the system is

notably incomplete. The review was largely confined to the potential effects on main channel

chemical

water column quality. It did not take into consideration the significant impacts that

frequent barge traffic in the

UAA Reach has on the aquatic biota or their preferred habitats

within the waterway as a whole.

The transportation of commodities along the UAA Reach continually affects the physical and

biological quality

ofthe system. The waterways are typically ice-free in the winter, allowing

barges

to navigate the UAA Reach year-round. Pool water levels are variably controlled to aid

barge navigation, as well as to reduce flooding, thereby eliminating environmentally beneficial

seasonal flushing events found in natural systems. The frequent manipulation

of pool levels and

flows to balance navigational requirements, along with the need

to release the magnitude of

excess water resulting from rainfall and snowmelt runoff, results in continuous disruptions to the

biota that are not found in natural systems. Due to the relatively narrow breadth

ofthe

waterway, surge effects from the barges continually disrupt the channel border areas and carry

fine-grained sediments into protected backwater and off-channel habitats. (Burton, 1995b)

The constant barge traffic through the

UAA Reach may adversely affect aquatic organisms,

particularly fishes, by:

(1) physically injuring

or stranding fishes,

(2) disrupting

or disturbing spawning habitat,

(3) uprooting aquatic vegetation,

(4) increasing turbidity via resuspension

of bottom materials, and

(5) enhancing toxicity by resuspending and dispersing the fine-grained sediments shown to be

associated with toxic compounds.

The net effect

of barge traffic on the UAA reach is to make the main channel and border areas a

less hospitable environment for most aquatic life and for recreational users alike.

15

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As acknowledged by U.S. EPA and well-established in the literature, the presence of dams

reduces the abundance and diversity

of riverine species. This is a result of interrupting or

eliminating migration, the pooling effect upstream

of each dam, the sediment that builds up

behind dams, etc. Species most effected are so-called fluvial specialists (e.g., most darters, many

suckers, etc.), whereas habitat generalists (e.g., common carp, gizzard shad, channel catfish), and

pelagic species (e.g. emerald shiner, freshwater drum) do quite well under impounded

conditions. Similarly, simple lithophiles (e.g., redhorse and most darters), which require clean,

hard substrates, do poorly

in impounded situations because of increased siltation while those that

are nest builders (e.g., centrarchids), or have modified spawning strategies (e.g., bluntnose

minnow) do quite well under the same set of circumstances.

The studies that

u.S. EPA conducted and/or sponsored on the Fox River clearly demonstrate

these impacts as shown by declines in

lEI scores upstream of each dam. The adverse impacts on

aquatic communities caused by dams are recognized by other Region 5 States. For example,

Wisconsin and Michigan are actively promoting dam removal. Ohio has a separate use

classification that recognizes effects from dams, as reflected by the subcategory

of their

Modified Warmwater Habitat (MWH) designation noted as "impounded".

In

addition, Ohio also

retains a MWH subcategory for "Channel-Modified" conditions. (See Table 7-15

of Ohio

Administrative Code, Chapter 3745-1, effective July

7, 2003).

A recent study by United States Geological Survey (USGS) and the Illinois Natural History

Survey (INHS) has documented direct mortality to aquatic life caused by towboats. Gutreuter et

al (2003) found that various medium to large fish were killed as a result

ofpropeller strikes in

Pool 26

ofthe Mississippi River, as well as the lower portion ofthe Illinois River. They

estimated that 790,000 gizzard shad were killed in just this area as a result

of propeller strikes.

The number

of fish killed was a function of the number of fish killed per kilometer times the

amount

of barge traffic (kilometers traveled). On a large river such as the Mississippi, at least

some fish will move away in response to oncoming barge traffic. (Lowery 1987, Todd et al

1989). In a smaller, narrower river like the Des Plaines, propeller avoidance would likely be

more difficult, so it is reasonable to assume that the mortality rate estimated for the Mississippi

River will at least be as high and may be higher in the Des Plaines River. So, in addition to

detrimental effects due to re-suspension

of sediment (contaminated and otherwise) and localized

changes in water levels due to barge traffic and storm water control, direct mortality to the

aquatic community due to barge traffic also has now been documented.

The system'shydraulic modifications are solely under the control

ofMWRDGC and the U.S.

Army Corps

of Engineers, and are in place exclusively to accommodate flood control and

commercial navigation. There is no indication that navigational/flow control and ensuing barge

traffic will ever be removed as a existing use for this waterway, as "navigation" is a protected

use under the Clean Water Act. (See Clean Water Act, § 303(c)(2)(A)). As such, it constitutes a

"permanent" modification which significantly precludes the attainment

offull General Use in the

UAA waterway under Factor #4

ofthe UAA criteria. (Appendix

1).

A considerable body of research has been collected during the past 20 years showing that

significant adverse impacts are associated with the type

of hydraulic modifications found in the

16

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UAA Reach. For similar conditions, other states, such as Ohio, have refined their use

classification systems to address the specific limitations posed by such modifications Here, even

the IEPA Consultant'sDraft UAA report acknowledged (See Draft

UAA Report, p. 8-16) that

expectations for the Upper Dresden Pool were lower because of hydraulic impacts and thus

suggested the creation ofa proposed use category called "General Use Impounded". Clearly,

the reasonable biological expectations for areas like the UAA Reach are lower than those

required for a General Use Classification System. The hydraulic modifications in the UAA

Reach support either retention

ofthe existing Secondary Contact use or creating a new use that

could include modified water quality standards and associated criteria to reflect the aquatic

community and recreational use limitations imposed by such adverse, persistent constraints.

C.

Pollutant Loadings to the UAA Reach

A major component ofthe flow to the UAA Reach, 70% or more ofthe flow upstream of

Brandon Road Lock and Dam is derived from treated wastewater discharges (Final Report, UIW

Study, 1995. p. 10.4-2). These discharges" by their nature and volume alone, remain a

significant influence on conditions for aquatic life in the UAA Reach, and the UIW as a whole.

A wide variety of industrial facilities line the shores ofthe UIW, particularly in the Lockport and

Brandon Pools. (There are no power plants that discharge directly into the Brandon Pool).

Discharges from these facilities are currently controlled by the NPDES permitting program,

in

accordance with the existing Secondary Contact Water Quality Standards.

Current monitoring data presented in the preliminary UAA reports indicate that water column

quality may have improved over the years to the extent that most General Use chemical criteria

are now being

met within the waterway below Brandon Lock and Dam, and possibly upstream as

well. (This subject is addressed in detail in the Hey and Associates' Draft Final UAA Report and

will not be described here). However, there are still many non-point sources, as well as

combined sewer overflows (CSO), that contribute to the overall pollutant loading to the system,

including its sediment contamination, and are not readily controllable through current regulatory

mechanisms. According to the U.S.

EPA's review ofthe states' 2002 section 303(d) Lists,

pathogens are the second most frequent cause ofwater quality impairments under the Clean

Water Act. Excessive nutrients are also among the top four leading causes ofwater quality

impairments. (U.S. EPA, August 2003). Hey and Associates found that the General Use fecal

coliform standard cannot be met in the UAA Reach and that nutrient standards not yet developed

but under consideration for Illinois General Use streams also may not be attainable in this

waterway (Draft UAA Report, Chapter 7)

D.

Extent and Physical Characteristics of Sediments in the UIW

From an aquatic ecological perspective, a significant stressor in the UAA Reach is the

accumulation of fine-grained sediments and the presence of legacy contaminants from historic

discharges. Next to structural habitat availability (discussed in the following section), the

physical nature

ofthe sediment in the UIW continues to be one ofthe most significant factors

adversely influencing the present and future expected assemblage

of aquatic biota present in the

Lower Des Plaines River.

17

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In the July 2002 U.S. EPA draft guidance on non-point source pollution, U. S. EPA identified

many detrimental effects on aquatic life caused by excessive sedimentation from urban run-off.

(U.S. EPA, July, 2002. p. 26-3 I) Sediment, whether contaminated or not, was found to be the

leading cause

of impairment accounting for 38% ofthe impaired waters in the nation. More

recently, the U.S. EPA reported that "[s]edimentation and siltation problems account for more

identified water quality impairments of U.S. waters than any other pollutant." (U.S. EPA,

August, 2003). Excessive erosion, transport and deposition

of sediment in surface waters is a

significant form

of pollution. Sediment imbalances impair many waters' designated uses.

Excessive sediment can impair aquatic life by filling interstitial spaces

of spawning gravels,

impairing fish food sources, filling rearing pools, and reducing beneficial habitat structure

in

stream channels.

While the UIW Study did not

quantifY the amount of sediment present within the waterway, it

did examine the types

of sediment present, as well as its depositional pattern, particularly as it

relates to the presence

of contaminated sediment in the waterway.

The extensive studies performed by ComEd in the mid

90's (Burton, 1995a and 1995b, and

1998, 1999) found that contaminated sediments occur in all three navigational pools and are

present primarily in side-channels and backwater areas. Sediment inputs from local drainages

appear to have covered the historically contaminated sediments in some areas, especially along

the lower reaches

ofthe Dresden Pool. However, substantial deposits of fine-grained and

potentially contaminated materials remain throughout the UIW, including in the limited habitat

areas in the UAA Reach, posing a permanent impediment to significant improvement of overall

ecological integrity

ofthe system. In a recently completed (EA. May, 2003) habitat evaluation

on the Dresden Pool, it was found that sedimentation was moderate to severe in many (23 out

of

34, or 70%) ofthe areas where QHEI scores were calculated. Sedimentation appears to have

gotten worse over the past 5-

I

0 years (e.g., DuPage Delta). (Maps of QHEI locations are

available upon request--large bmp files: 9.8MB).

A key limiting factor to improved biological conditions in the UAA Reach is the physical

characteristics

ofthe sediment itself (i.e., fine, silty, organic). The fine, silty and organic nature

ofthe sediments are not suitable for many higher quality fish species which need a hard, clean

substrate for spawning. Even

ifthe stream could be remediated and the existing sediment

(contaminated or not) removed, the nature

ofthe waterway itself (e.g. impounded) would ensure

that additional fine, silty sediment (whether clean or contaminated) would continue to be

deposited, thereby preventing an improved habitat for better quality aquatic life. The

unpreventable and irreversible accumulation and physical quality

ofthe sediments that will

always be present in the system

is limiting further biological improvements in the UAA Reach,

with existing, depositional area sediment contamination exacerbating the fundamental siltation

problem.

As part of ComEd's UIW Study, conducted from 1991-1995, a thorough literature review (EA,

1992), followed by a detailed risk screening (LMS, 1995), defined historic patterns

of sediment

contamination in the Lower Des Plaines River and identified the following list

of contaminants

of special concern: ammonia, arsenic, cadmium, chlordane, chromium, copper, DDT,

dieldrin, lead, mercury, nickel, PCBs, PAHs

and zinc.

18

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Intensive sediment and immediately overlying water column samples were subsequently taken

and analyzed as part

ofthe UIW study. (Burton, 1995a) Toxicity varied among pools and

habitat types. Differences were correlated with sedimentation patterns. Fine-grained sediments

from depositional areas were found to be the most toxic. Overlying waters also were found to be

toxic. These fme-grained, contaminated sediments tend to occur at the tributary mouths and

in

backwater and protected areas ofmain channel border habitat---especially in the Lockport and

Brandon Pools. These contaminated sediment depositional areas provide the primary source

of

potential habitat for the fish community. As such, the fish are likely exposed to whatever

contamination currently exists within these specific areas. In contrast, sediments collected from

main channel habitat and power plant intakes and discharges throughout the UIW generally had

no or very little sediment toxicity. However, these areas do not provide suitable aquatic habitat

for most aquatic organisms.

Monitoring by the Illinois Department

of Natural Resources (IDNR) has shown significant body

burdens

of contaminants in adult, bottom-feeding fishes within the UAA Reach, as well as

elsewhere

in the UIW. These results are used by the Illinois Department of Public Health

(IDPH) to establish annual human health risk advisories. (IDNR, 2002-2003 and IDPH, 2002-

2003) There is an on-going consumption advisory for bottom-feeding fish species in effect for

the Dresden Pool,

as well as the upstream reaches and further downstream. This fish

consumption advisory is clear and continuing evidence

ofthe prevalence and persistence of

sediment contamination in the UAA Reach.

The highest levels

oftoxicity were found in sediments collected between the junction ofthe Cal-

Sag Channel and the Chicago Sanitary and Ship Canal and the Brandon Road Lock and Dam

tailwaters. The Brandon tailwater area has been previously identified

as the best quality aquatic

habitat

in the UAA Reach, based on its physical characteristics. (These are the same

depositional areas AquaNova and Hey and Assoc. identify as potential "recreational use" waters

(littoral zones)). Sediment toxicity in the Dresden Pool was more variable than in the two upper

pools, with effects observed predominantly on growth. Toxicity was not restricted to the surface

sediments, as much

ofthe historic deposition has since been covered over by cleaner material.

More recent sediment sampling in the UAA Reach was performed by

u.S. EPA Region 5 during

the summer of2001. Results

ofthis investigation only have been released as part ofthe draft

UAA Report, and have not undergone prior review by the UAA Biological Subcommittee or the

UAA Workgroup. A thorough review

ofthis data should be conducted as part ofthe overall

evaluation

ofthe future use potential ofthe waterway; however, these results must also be

viewed with caution. Sediment is so heterogeneous and selectively dispersed in the system that

unless a large quantity

of samples are taken and analyzed, as was done in the previous UIW

Study, the sampling may not be fully representative ofthe UAA Reach. Areas of significant

contamination may be missed by a random sampling program. The draft UAA Report presents

only average sediment sampling values from the

u.S. EPA sediment sampling database. This

partial

di~closure

ofthe U.S. EPA 2001 sediment sampling results does not allow for a

meaningful, scientific assessment ofthe data. The average values do not reveal whether they

reflect either a broad

or narrow range of individual sediment sampling location results.

19

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Grouping sediment data together to present only an "average" concentration of chemicals/metals/

toxics does not provide a true picture

of where the specific areas of contamination are or the

associated contamination levels. Averaging dampens

out the heterogeneity of sediment quality

and distribution, which is an extremely important factor in determining the adverse exposure

levels sediment present to biological organisms. The data presented in the draft UAA Report

does not disclose or differentiate between sediment sample type(s) or specific sampling site(s) at

any given River Mile location. Thus, there is no way to determine if it reflects the results of

main channel or side-channel/backwater areas. As explained above, sediment distribution (and

any associated contamination) is extremely heterogeneous in nature within the UAA Reach.

Depositional areas that would otherwise provide available fish habitat, such as those found just

above or below lock and dams or backwaters/side channels, have large accumulations

of

sediment, while locations near the main channel may have sparse or no sediment accumulation,

due to the scouring effects

of barges and sporadic high river flows. Accordingly, sediment

sampling results that average the values across various types

of sediment areas will likely

understate the levels

of sediment toxicity present in the aquatic habitat areas in the UAA Reach.

In contrast, the sediment data obtained during the course

ofthe UIW studies has been fully

disclosed and peer reviewed.

It

represents the most comprehensive record available of current

sediment quality and composition in the system, as well as how its presence in various locations

relates to habitat quality and toxicity, within the UAA Reach and beyond. Since sediment

characteristics do not change appreciably over a few year'stime, the results

ofthe UIW sediment

characterization/toxicity work remain valid and applicable to this UAA process. A thorough and

reliable assessment of sediment quality is critical to the overall use designation assessment ofthe

Lower Des Plaines River.

It

affects the assessment of both biological habitat quality andthe

long-term potential for future recreational activity in the waterway. As noted earlier, the areas

that are the most important biologically are also the areas that have been found to be the most

contaminated.

The IEPA consultants assume that any contaminated sediments can be removed permanently and

are not a limiting factor to the overall improvement

ofthe waterway. However, this

contamination is the result

of historic deposition. It is not solely due to current point source

discharges which could, theoretically, be controlled through tighter NPDES permit limits. No

proposal, plan or funding has yet been identified by anyone that would remove the biological

limitations these sediments (contaminated and otherwise) place on the UAA Reach and prevent

them from reoccurring.

Even

if remediation of any historically contaminated sediments was feasible, the impounded

nature

ofthe waterway will result in the continual deposition of fine, silty sediments, especially

in the main-channel

,

border,

'

side-channels and backwaters where the majority

of aquatic

organisms reside. This type of sediment, as well as the continual barge traffic that affects its

ultimate location in the waterway, is not conducive to the development

of an improved

biological community. The physical quality

ofthe sediments in the system will continue to limit

further biological improvements, with existing, depositional area sediment contamination

exacerbating the siltation problem. The presence and persistence

of fine-grained sediments in

the UAA Reach constitutes a "lack

of proper substrate..., unrelated to water quality," within the

20

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meaning ofthe UAA regulations (UAAFactor #5), that preclude the attainment of aquatic life

protection uses.

E.

Effect of Temperature on Contaminated Sediments

Generalizing on the effects that elevated water temperatures may have on contaminants in the

UIW is a difficult task. Elevated water temperatures may increase the rate

of chemical or

biological degradation

of complex organics, strengthen or weaken the physical or electrostatic

bonding

of toxicants to inert substrates or to other chemical molecules, increase or decrease the

rates at which organisms take up materials, increase physiological capabilities

ofthe organism to

eliminate or metabolize toxicants, thereby altering the level

of concentration ofthe chemical at

which toxic effects are expressed, and so on. Since it has been shown that the thermal discharges

to the system are buoyant and do not generally affect the lower portion

ofthe river, the sediments

are not likely exposed to high water temperatures and should not be impacted by them, either

positively or negatively. (Burton, 1995a) In any event, the overriding negative effects caused

by the levels

of contamination that remain present in the system, as well as the presence of fine-

grained sediments themselves, regardless

ofwhether they are contaminated or not, pose a

continuing concern for the future potential

ofthe waterway to meet a higher use.

F.

Physical Habitats

1. Types and Availability

of Physical

Habitats

An obvious requirement for a diverse aquatic biota is a suitable variety of living spaces. As part

ofthe original UIW study performed by CornEd, the entire UIW was surveyed to determine the

types, distribution and relative amounts

ofphysical habitats available in the three navigational

pools. (Habitat definitions conventional for large rivers and reservoir systems were used in the

survey). These habitat classifications are still valid today, as they are based on physical

characteristics

ofthe waterway, that have not changed appreciably since the UIW study. (EA,

1993)

Main Channel:

Main Channel Border:

Backwaters, Sloughs and

Artificial Embayments:

Tributary Deltas:

Tailwaters:

Tributary Mouths:

IntakelDischarge Embayments:

51.6%

22.4%

10.4%

7.0%

4.6%

3.0%

1.0%

The preponderance

of habitat available

in

the system is main channel (MC) and main channel

border (MCB), areas where the effects

ofbarge transport and industrial and municipal discharges

are especially dominant. Main channel habitat, which accounts for more than 50%

ofthe

available area, is poor habitat for most fishes owing to excessive depths, scour and lack

of food

resources. Protected backwater areas and tributary mouths are almost non-existent in the

Lockport Pool and uncommon in the Brandon Pool. These two upper pools are primarily

artificial or dredged waterways with a uniform bottom and shear rock, piling or rip-rap borders.

21

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A greater diversity of habitats is available downstream in the Dresden Pool, although these are

still adversely affected by barge traffic and historical sediment deposition.

2. Physical

Habitat Quality

Quantitative techniques for evaluating physical habitat in large river systems are generally

lacking. Although it has shortcomings and limitations, the best quantitative system available for

the UIW is the Qualitative Habitat Evaluation Index (QHEI) (Rankin, 1989). This numeric index

ranks aquatic habitats as to selected attributes, availability and desirable quality characteristics.

The outcome is a numeric score (ranging from 0-100) that allows comparison

of habitats from

other aquatic systems. The higher the numeric score, the better the quality

of aquatic habitat in

the waterway. The points allotted for the QHEI scores are divided as follows: Substrate (20

pts), Cover (20 pts), Channel Morphology (20 pts), Riparian Zone (10 pts), Pool/Riffle Quality

(20 pts) and Gradient (20 pts).

The UIW studies found that average QHEI scores for the different habitat types ranged from 42

to 69, with the higher values attributed only to tributary mouths, a small riffle-run area in the

Upper Des Plaines River, and the Brandon Road tailwater. The predominantly low scores reflect

the artificial nature

ofthe system and the limited variety of habitat. Channelization, inadequate

in stream cover, lack

ofriffle-run habitat, excessive siltation, lack of clean, hard substrates, and

poor quality riparian and floodplain areas all contribute to the low QHEI scores.

The UIW study also found that habitat conditions were poorest in the Lockport Pool (mean

QHEI

= 45.3), marginally better in the Brandon Pool (mean QHEI = 48.6) and better still in the

Dresden Pool (mean QHEI

= 54.8). However, even the best ofthese three QHEI scores is well

below values typical

ofunaltered systems of comparable size. For example, Ohio EPA identifies

a target minimum value

of 60 as necessary to assume a potential for warmwater habitat use. All

of the QHEI scores for the UAA Reach, except for the Brandon Road tailwater, were well below

the target score

of 60 that would be the Ohio equivalent to consider a General Use designation.

A more recent and more extensive habitat evaluation study was performed by EA Engineering,

Science and Technology ("EA") in May 2003 on the entire Dresden Pool. QHEI scores were

calculated along both banks

ofthe river at 0.5 mile intervals throughout the pool. Field

biologists from Illinois EPA accompanied EA during this investigation. Results are presented in

Tables lA and IB. The results ofthis 2003 study show that habitat conditions today in the UAA

Reach remain relatively unchanged from when first reviewed as part

of the comprehensive UIW

studies conducted in the early to mid-1990s. In fact, average scores now are even lower than

they were in the mid-90's. The recent QHEI scores for the UAA waterway are all clearly well

below what would be expected for a General Use stream under the Illinois use classification

system. EA personnel reviewed the QHEI scores collected at all 34 locations and determined

that poor habitat is pervasive throughout the Pool. IEPA biologists, present throughout the

evaluation process, concurred that the entire area "looked the same" (Joe Vondruska, EA,

personal communication).

Modifications to the QHEI factors which could improve overall habitat should be considered by

Illinois EPA and its consultants as part

ofthe UAA analysis. On the whole, however, the

22

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individual QHEI metrics which are the major contributors to degraded habitat quality are those

that cannot be feasibly or economically reasonably mitigated, including insufficient current

speed, sediment quality (physical characteristics

ofthe sediments), excessive siltation, lack of

riffle areas, little or no sinuosity and poor riparian development (Table IC).

Table lA. Des Plaines River QHEI Scores, 21 May 2003.

Upstream 155

Downstream 155

QHEI Score

QHEI Score

RM

Right Bank

Left Bank

RM

Right Bank

Left Bank

285.5

65.5 (TW)*

48 (MCB)

277.5 (408)

28 (MCB)

45.5 (MCB)

284.5

47.5 (MCB)

36.5 (MCB)

276.5

39 (MCB)

42 (MCB)

283.8 (403A)

43.5 (MCB)

39 (MCB)

275.5

49.5 (MCB)

57 (MCB)

282.5

35.5 (MCB)

36.5 (MCB)

274.4 (419A)

60 (MCB)

40 (MCB)

281.5

36 (MCB)

36 (MCB)

273.5 (501)

54.5 (MCB)

28 (MCB)

280.5

38 (MCB)

41 (MCB)

272.5

56 (MCB)

37 (MCB)

279.5

59 (MCB)

49 (MCB)

272.0 (510/507)

51 (MCB)

32.5 (MCB)

278.5

56 (MCB)

48 (MCB)

Overall Mean

= 44.7

(Range

= 35.5-65.5)

* Habitat Type:

TW

=

Tailwater

MCB

=

Main Channel Border

Table IB. QHEI Scores at Off-Channel Locations.

Location

Score

405--Treats

53

Island

(RM

279.7)

40~--Mouth

of

54.7

Jackson Creek

(RM 278.3)

414--Bear

40.5

Island Slough

(RM

275.9)

418--Mouth

of

57.5

Grant Creek

(RM

274.8)

Overall Mean

= 44.3

(Range

= 28-60)

23

---

Provided below are the 10 major components ofthe QHEI that contributed to the low scores:

Table 1C--Dresden Pool Individual QHEI Factors--May 2003

Factor

No. of Locations Affected (out of 34)

Poor Development (of riffles)

ALL

No Riffles

32

Current Speed None or Slow

32

Recent Channelization or Lack or

30

Recovery

No Sinuosity

23

Moderate to Heavy Silt

23

Extensive or Moderate/Extensive

19

Embeddness

Only Substrate Silt or Detritus

10

Poor

(=::;

6) Instream cover

8

Urban or Industrial Riparian Zone

6

Practically speaking, these factors either cannot be remediated (e.g. lack of sinuosity, substrate

only silt) or the effort to remediate them, (e.g., the amount

of instream cover) would be

unprecedented for a stream

ofthis size.

In addition,

EA reviewed the habitat characteristics ofthe Brandon and Upper Dresden Pools and

compared them to

Ohio's use designations for Warm Water Habitat (WWH) and Modified

Warm Water Habitat (MWH) to provide additional analysis, as requested

by U.s. EPA. The

results

of this effort are presented in the following table (Table ID), which was compiled based

on the same criteria used by Ohio

EPA to determine whether an area should be classified as

WWH or MWH. As these data show, both the Brandon and Upstream Dresden Pool areas share

many

ofthe characteristics of modified warm water habitat streams, and except for depth,

possess

none ofthe characteristics associated with warm water habitat streams.

24

---

Table ID. Comparison of warm water habitat (WWH) and modified warm water habitat

(MWH) characteristics ofthe Des Plaines River.

Brandon Pool

Upper Dresden Pool

WWH Characteristics

No Channelization or

Recovered

Boulder, Cobble, Gravel

Substrates

Silt Free

Good-Excellent

Development

Moderate-HiQh Sinuosity

Cover Moderate to

Extensive

Fast currents

& Eddies

Low/Normal Substrate

Embeddness

Max Depth> 40cm

X

X

Low/No Riffle embeddness

TotalWWH

1

1

Characteristics

MWH Characteristics

with

High Influence

Recent Channelization

Silt/Muck Substrates

X

X

No Sinuosity

X

X

Sparse/No Cover

X

X

Total MWH (High)

3

3

MMH Characteristics With

Moderate Influence

Recovering Channelization

X

X

High or Moderate Silt Over

Other Substrates

Sand Substance (Boat)

Fair/Poor Development

X

X

Low Sinuosity

Only 1-2 Cover Types

Intermittent or Interstitial

Max Depth

< 40cm

High Embeddness

of Riffle

X

X

Substrates

Lack

of Fast Current

X

X

Total MWH (Moderate

4

4

Total

MWH (All)

7

7

25

---

With regard to the approach summarized in Table 1D, Yoder and Rankin (1996) stated that "as

the predominance

of modified habitat attributes increase to a modified warmwater ratio of

greater than 1.0-1.5, the likelihood of having IBI scores consistent with the WWH use declines."

In both Brandon Pool and Dresden Pool, the ratio is

7: 1, far greater than 1.5: 1 trigger point

suggested

by Yoder and Rankin. Thus, it is clear, based on this well established methodology,

that neither

ofthese areas is capable of attaining a Warmwater (i.e.General) Use, so some lower

classification

is clearly warranted.

These unalterable limitations in the physical conditionslhabitat features

ofthe waterbody, even

without the presence

of contamination, preclude the attainment of aquatic life protection uses

consistent with General Use requirements. Therefore, these limitations meet the requirements

of

factor #5 ofthe UAA criteria for determining that General Use is not an attainable use

designation for the UAA Reach. (Appendix 1).

Also, in the May 2003 EA study, no significant differences were found between habitat type or

availability upstream or downstream

of I-55. Similarly, the fish community downstream ofI-

55, where General use thermal water quality standards are in force, is not appreciably better than

the fish community upstream

of I-55, where Secondary Contact thermal limits are effective.

This demonstrates that the maintenance

of General Use thermal standards in the area

downstream

ofI-55 does not allow attainment ofa fish community commensurate with a General

Use designation. The fish community is comparable upstream

ofI-55 where the less restrictive

thermal Secondary Contact standards apply.

Ifthermallevels made any appreciable difference,

this would not be the case. Clearly, there are factors like the absence

of adequate habitat in the

Lower Des Plaines River, not thermal levels, that are limiting the assemblage

of aquatic

organisms present in the waterway.

The absence

of adequate habitat limits the fish species that can inhabit the UAA Reach. Fish

species whose natural history minimizes contact with the sediments or that are highly tolerant

of

degraded conditions, that preferentially attach to "clean or non-silty" substrates such as rocks or

rip-rap around power plant intakes, are pelagic in nature or that prefer to live along rocky

submerged cliffs, can be expected to inhabit the system. However, most aquatic species,

especially fishes, require a sequence

ofvarying habitat types as they proceed through the

different life stages. The .overalliack

ofhabitat diversity in the UIW represents a serious

impediment to the development

of a more diverse resident aquatic biota consistent with a

General Use designation. (Final Report, UIW Study, 1995.

p. 2.6-1)

G.

Limitations of the Illinois Use Classification System

Section 303(c) ofthe Clean Water Act provides that in setting water quality standards, States

should consider the following factors: the use and value

of State waters for public water supplies,

propagation

of fish and wildlife, recreation, agriculture and industrial purposes, and navigation.

(See also 40 CFR

§131.1 O(a». Thus, the Act allows the States to consider the use and value of

the particular water body in determining its appropriate use designation. Within these directives,

a state has the flexibility to develop and adopt whatever use classification system, including

subcategories

of uses, it deems appropriate. For example, Section 303(c)(2)(A) ofthe Clean

26

---

Water Act includes "industry", "navigation", "marinas" and "agriculture", among the many

suggested use designations for a water body.

However, Illinois has only two generic use designations for inland waterways: Secondary

Contact and Indigenous Aquatic Life and General Use. The General Use classification is a broad

aquatic life use that assumes a water body will support all aquatic life and all types

of

recreational uses.

It

does not differentiate among aquatic communities or the physical

characteristics

of a water body. Illinois also has not developed any use subcategories under its

existing use classification system. As the U.S. EPA has noted, making a determination

of non-

attainment in waters with broad use categories may be difficult and open to alternative

interpretations. (See

Water Quality Standards Handbook: Second Edition,

U.S. EPA, August

1994, Section 2.4,

p. 2-5). Due to the lack of any refined delineation ofuse classifications in

Illinois, there is a regulatory bias in favor of designating or "defaulting" waterways to the

General Use classification.

In U.S.EPA's Water Quality Standards Handbook (Second edition. 1994--p.2.5), the Agency

discusses the need for sub-categories

of use in certain cases:

"Designated uses are described as being intentionally general. However, States may

develop subcategories within use designations to refine

and clarifY the use class.

Clarification ofthe use class is particularly helpful when a variety ofsurface waters

within distinct characteristics

fit within the same use class, or do notfit well into any

category."

(emphasis added).

In the newly published "Strategy for Water Quality Standards and Criteria" document (U.S.

EPA, August, 2003), it was stated that "assigning tiered designated uses is an essential

step in

setting water quality standards." EPA'sOffice of Science and Technology (OST) agrees that

refined uses including biologically "tiered" uses can improve the effectiveness and credibility

of

state and tribal standards in many situations. "Many states are learning that refmed uses offer

advantages for waterways where information is available to develop them. For example, they

can provide better operational definitions

of desired outcomes, and can provide flexibility to

describe locally-important variations that broad uses cannot." (EPA Strategy for Water Quality

Standards

and Criteria--August, 2003. EPA-823-R-03-010, p. 24 ).

Other Region 5 states either already have or are in the process of refming and expanding their

use classifications. Ohio has four warmwater aquatic life use classifications. Their very best

streams are classified as Exceptional Use. The majority

of Ohio streams are classified as

Warmwater Use; this use would be equivalent to Illinois' General Use. The next lower Ohio

classification is Modified Use, which they further subdivide depending on the type of

modification, e.g., Impounded (dams), Channelized, or Acid Mine Drainage. Thus, Ohio clearly

recognizes that dams, due to their impounding effect, can necessitate a lower use classification.

Lastly, Ohio has a category called Limited Resource Water, which is their lowest classification.

In some cases, water quality criteria are adjusted to provide the level

ofprotection necessary to

protect each

of Ohio's uses.

27

---

In comparison to Illinois' existing use designations, the state of Ohio'suse classification system

has a range

of acceptable use designations based on measured physical, chemical and biological

criteria. In Ohio's use designation guidance documents, the Ohio EPA has noted that sites with

QHEI scores of less than 60 often do not support balanced, indigenous aquatic communities.

(Ohio EPA, 1989a) Ohio EPA also notes that streams with gradients <5 ft/mile (as is the case in

the UAA Reach) are very slow to recover or may not recover at all, resulting in an "irretrievable

anthropogenic modification".

Wisconsin is in the process of developing new and more refined uses and has prepared

(November 2002) a Draft document entitled "Guidelines for Designating Fish and Aquatic Life

Uses for Wisconsin Surface Waters". For warmwater, Wisconsin is proposing the following

categories: Diverse Fish and Aquatic Life (which they propose to further subdivide), Tolerant

Fish and Aquatic Life, and Very Tolerant Aquatic Life. These categories would be quite similar

to Ohio's Warmwater, Modified Warmwater, and Limited Resource Water uses, respectively.

The draft Wisconsin guidance lists the factors which would allow one oftheir streams to be put

into one ofthe two lower use categories. Three ofthe reasons they cite are particularly relevant

to the

UAA Reach:

1)

"Dams, diversions or other types ofhydrologic modifications preclude the attainment of a

Diverse Fish and Aquatic Life community, and it is not feasible to restore the water body

to its original condition or to operate such modification in a way that would result in the

attainment of a Diverse Fish and Aquatic Life community."

Thus, Wisconsin, like Ohio, recognizes the negative effect that dams can have on aquatic

life.

2)

"Human caused conditions or sources

ofpollution prevent the attainment of a Diverse

Fish and Aquatic Life community and cannot be remedied or would cause more

environmental damage to correct than to leave in place."

They go on to note that "This condition can occur where years

ofpoor land management

have resulted in sediment and nutrient deposits in streams and other water bodies. These

deposits can result

in habitat destruction and degraded water quality. These conditions

may not be attributable to one source and cannot be remediated through enforcement or

reasonable management actions. Degraded habitat or water quality will likely continue to

persist even with better land management in the watershed."

The problem

of legacy sediment contamination in the UAA Reach clearly would fall

under this definition.

3)

"Physical conditions related to the natural features

ofthe water body, such as the lack of

proper substrate, cover, flow, depth, pools, riffles, and the like, unrelated to water quality,

preclude attainment of a Diverse Fish and Aquatic Life community."

Wisconsin proposes to apply this to situations where the lack ofthese features is a result

ofthe natural condition ofthe waterway. Nonetheless, it is a clear acknowledgement that

28

---

these factors, whether a result of natural conditions, or from the damming of a river, as in

the UAA Reach, has severe consequences to the biota.

Given the precedents established by these other Region 5 states, Illinois should give strong

consideration to developing one or more new and more appropriate use categories.

In its

Water Quality Standards Handbook,

the U.S. EPA offers some guidance in establishing

subcategories

of use designations. The U.S. EPA nOtes that subcategories of aquatic life uses

may be based on: attainable habitat

(e.g.,

coldwater versus warmwater habitat); innate

differences in community structure and function

(e.g.,

high versus low species richness or

productivity); or fundamental differences

in important community components

(e.g.,

warmwater

fish communities dominated by bass versus catfish).

(Water Quality Standards Handbook:

Second Edition,

U.S. EPA, August 1994, Section 2.4). The U.S. EPA also suggests using

biological data as a basis for creating subcategories, such as using measurable biological

attributes to create a use subcategory.

Id

In general, the U.S. EPA supports the use of greater specificity by states in defming use

classification systems.

It

is considering revisions to the water quality regulations that would

require more precise use designation systems by the states. In its 1998 Advanced Notice of

Proposed Rulemaking on the Part 131 water quality regulations, the U.S. EPA said:

[T]he Agency'scurrent thinking

is that there is a growing need to more precisely

tailor use descriptions and criteria to match site-specific conditions, ensuring that

uses and criteria provide an appropriate level

ofprotection which, to the extent

possible, is neither over nor under protective. 63 Fed.Reg. 36750 (July 7, 1998).

The discussions held during the recent U.S. EPA-sponsored national symposium entitled

"Designating Attainable Uses for the Nation's Waters" (GLEC, July, 2002) also

highlighted the current need for more refined designated uses with more differentiated

criteria applicable to site-specific waterbodies.

For Illinois, the development

of additional use classification designations to address those waters

which fall between Secondary Contact and General Use may be an appropriate course

of action

to further evaluate the proper use classification

ofthe UAA Reach

l

.

The Lower Des Plaines River data reveals that in some ways it can attain uses that are higher

than those included in the Secondary Contact Use designation. However, the application

ofthe

UAA regulatory factors shows that

it cannot attain a General Use designation. The alternative

of creating a new use designation or a subcategory that incorporates an appropriate hybrid of

General and Secondary Use water quality standards is an option that would be consistent with

U.S. EPA guidance and current thinking on use classification systems.

I

The Clean Water Act regulations require an opportunity for public hearing before a State may establish a use

subcategory. See 40 C.P.R.

§ BUO(e).

29

---

An additional use category would allow the State to recognize and maintain the improvements

that have been made in the Lower Des Plaines River chemical water quality over time, while also

accurately concluding that certain fishable/swimmable uses are not attainable. Under such an

additional use category, less stringent limitations are justified and warranted for those parameters

which are not responsible for limiting the existing and potential indigenous aquatic community

or preventing full recreational uses

in a physically compromised system.

VIII. POWER PLANT EFFECTS ON THE WATERWAY

A. Effects

of Power Plants on Physical Habitat

Power plants add to the availability ofphysical habitats in a localized but generally

positive way. Intake and discharge embayments provide protected off-channel refuges. High

velocities in the discharge areas tend to scour fine, contaminated sediments. Discharge water

temperatures during mid-summer reach levels sufficient to exclude many

ofthe more heat-

sensitive fish species from the hottest portions

ofthe plumes, but the areas affected are quite

small. These same areas attract fish during the colder months

ofthe year. Thermal plume

observations conducted in connection with the UIW study in 1993-1994 revealed that in each

instance at least 75% ofthe cross-section ofthe stream was in compliance with applicable

thermal standards, providing a zone

of passage for potentially affected organisms. (Final Report,

UIW Study, 1995. Chapter 3). The data collected during the 2002 Joliet thermal plume studies

conducted by

EA for Midwest Generation, during typical summer operating conditions, showed

that the two thermal plumes from the Joliet Stations are continuing to meet both the mixing zone

and zone of passage requirements of302.102 in the context ofthe existing Secondary Contact

thermal water quality standards (EA, 2003,

p.B-15). Being surficial in nature, the thermal

plumes from Midwest Generation's plants have no negative impacts on the existing physical

habitats for aquatic life in the Lower Des Plaines River.

B. Water Temperature Regime

Generally, main channel water temperatures in the entire UIW tend to be warmer year round than

would be expected for a river

of comparable size in this geographic region. As an effluent-

dominated waterway, the primary causes

ofthe elevated thermal regime in the UIW are

discharges from power plants and wastewater treatment plants (WWTP). WWTPs contribute a

large component ofthe flow (l00 % during low flow periods) and their discharges tend to have a

relatively constant, moderate temperature which has the effect

of dampening seasonal and

diurnal changes. While power plants do not change the volume

of flow, they add heat and raise

the water temperatures not only near the plant, but progressively downstream. The increases in

incremental temperature gradually diminish as heat is lost to the atmosphere, but overall water

temperatures do increase from the Chicago Metropolitan area to the Joliet area, due to a

combination

of ambient solar heating, WWTP discharges, power plant contributions and non-

point source sheet runofffrom urbanized areas

.. (Final Report, UIW Study, 1995. Chapter 3).

The UIW study confirmed the cyclic nature ofboth temperatures and organism life stages in the

waterway. Because nearly all temperate zone organisms normally live in temperatures that cycle

annually, it is assumed that maintenance

of a seasonal cycle is important. Thermal modeling

30

---

shows that water temperatures in the system are higher than they would be without the power

plants in operation, but that the seasonal cycle is nonetheless preserved. The UIW studies

observed actual conditions associated with power plant operations.

It

also confirmed that

biological cycles are maintained in the waterway. The timing

of biological cycles did not appear

to be altered significantly, although some shifts probably do occur because the temperature cycle

in the waterway cannot be considered "natural".

c. Longitudinal Temperature Distributions

The variability

in temperatures inherent in the water source inputs to the UIW, atmospheric

conditions (largely unpredictable), and operations

ofthe power stations make concise,

quantitative portrayal

of longitudinal temperatures throughout the system extremely difficult.

Midwest Generation uses predictive mathematical models to extrapolate hypothetical

temperature distributions assuming fixed representative inputs and atmospheric conditions. The

reliability

ofthese models to depict realistic conditions has been confirmed for a wide range of

. seasonal and operational circumstances. (Holly, et. aI, 1994-1995)

All

ofMidwest Generation'spower plants in the UIW utilize once-through, open cycle cooling

systems. Each plant takes relatively large volumes of water through its condensers and

discharges

it directly back into the waterway at an elevated temperature. Stations must meet the

current Secondary Contact thermal limitations at the edge

ofthe allowable mixing zone.

Compliance is monitored by reporting end-of-pipe temperatures, per NPDES permit

requirements. Compliance

is verified internally by performing mass-balance calculations to

determine the fully mixed waterway temperature. Field verification studies have been

performed, including the field studies performed by ENSR as part

ofthe UIW Study (ENSR,

1995) , as well

as more recent studies (EA, 2003) that demonstrate compliance with the

Secondary Contact thermal limits at the edge ofthe allowed mixing zone.

The UIW thermal modeling analysis shows that the overall thermal regime

ofthe waterway

downstream

ofthe MWRDGC'sStickney Water Reclamation Plant (WRP) is influenced more

by the temperature

ofthe Stickney WRP treated effluent discharge than by any upstream

temperatures: warmer

in the winter, cooler in the summer. Therefore, any impacts on

temperature from the operation

ofMidwest Generation'sFisk and Crawford Plants (located

upstream ofthe Stickney WRP and approx. 33 River Miles upstream of the UAA Reach) on the

Lower Des Plaines are negligible.

D.

Non-Summer Water Temperatures in the Lower Des Plaines River:

While summer temperatures have been the primary focus

in the draft UAA report, non-summer

temperature limits also need to be adequately addressed

in the course ofthe this UAA evaluation.

There are periods during the Winter and Spring when ambient river temperatures currently

exceed the corresponding General Use thermal water quality limit, largely due to the influences

ofthe MWRDGC's Stickney Water Reclamation Plant (the "Stickney WRP"). The Stickney

WRP provides up to 100

%

ofthe flow to the waterway during the winter months. Its discharge

elevates UIW temperatures above what would be found

in a natural waterway during this time

31

---

of year. The result is an altered thermal regime, regardless ofthe input of heat from MWGen's

plants.

This phenomenon is substantiated by MWGen'stemperature monitoring data upstream of the

UAA study reach that indicates ambient water temperatures often exceed the General Use

thermal water quality criteria limit of 60 of / 63 of during the winter months. This is largely

due, as indicated above, to the significant influence

ofMWRD'streated wastewater discharge on

the waterway. Unless the temperature ofthis dominant discharge is controlled to ensure that

downstream ambient temperatures meet the General Use criteria, the "natural" (in so far as

anything can be considered natural in this waterway) background temperature ofthis waterway

will remain elevated during the Winter and Spring months.

The Cal-Sag Channel enters the Chicago Sanitary and Ship Canal between the Stickney WRP

discharge and Will County Station. Inflow temperatures from the Cal-Sag tend to be very

similar to those at the Roosevelt Road Bridge (the most upstream influent point in the UIW

system). Proceeding downstream, the next significant thermal input in the Lockport Pool (aside

from the MWRD discharge during the winter months) is the discharge from Midwest

Generation's Will County Station. Some ofthe heat from the Will County Station'sdischarge is

gradually dissipated to the atmosphere along the approximately five mile reach from the Station

to the Lockport Dam. This cooling continues for another mile and a

half below the Lockport

Dam, at which point it is further diluted by the discharge from the upper Des Plaines River.

Inflows from the upper Des Plaines tend to have a cooling effect on the Lower Des Plaines River

year-round, although the volume

oftotal flow contributed is minimal.

Joliet Stations #9 and #29 are located in the Dresden Pool approximately a mile downstream of

Brandon Road Lock and Dam. The waterway in this lower pool has a moderately large cross-

sectional area (and surface area) and water movement downstream is relatively slow. A

substantial portion ofthe heat input from the Joliet Stations is lost to the atmosphere before the

flow reaches the I-55 Bridge located approximately seven miles downstream--the point at which

General Use water quality standards begin.

Five miles downstream ofI-55, the mixing ofthe Lower Des Plaines River with the cooler

waters

ofthe Kankakee River further reduces the water temperature. However, the inflow ofthe

Kankakee tends to be compressed along the south bank ofthe channel such that full mixing (and

reduction ofthe temperature by dilution) does not occur until downstream ofthe Dresden Island

Lock and Dam. (Holly, et. al. 1995)

E. Lack of Thermal Effects on Phytoplankton and Zooplankton

The warmest areas in the UAA Reach occur in the near-field plumes immediately downstream of

the points of discharge from Midwest Generation's power plants. Important questions associated

with possible near-field impacts include whether these temperatures are sufficiently high to kill

or injure planktonic organisms passing through the plants' cooling systems, whether mobile

organisms will be excluded from areas in the immediate discharge vicinity, and whether the

movements

of mobile organisms up and down the waterway will be blocked by elevated

temperatures that might completely occupy the cross-section near any particular station. The

32

---

UIW Study components were designed to respond to these questions. More recent information

(EA, 2003) also confirms the limited extent

of influence ofthe thermal plumes from MWGen's

Joliet plants on the lower Des Plaines River under typical summertime operations.

The UIW Study showed that truly planktonic forms of algae (and presumably zooplankton) make

up a very minor component

ofthe flora and fauna in the UAA Reach. (Final Report, UIW

Study, 1995. Chapter 5). For the most part, planktonic organisms are represented by species that

attach

to or are closely associated with the substrate--periphytic algae and grazing zooplankters.

The UIW Study results indicate that phytoplankton densities generally increase with distance

downstream. These increases are related to an expansion

of available habitats in the lower pools,

the input

ofplankton from tributaries in these pools, and to some extent, from increased growth

rates due to elevated water temperatures.

Previously done studies documented in the

UIW report, as well as the monitoring work done for

the

UIW study, confirm that algae in the UIW system have little susceptibility to entrainment and

that similar community structure and abundances are found throughout the UIW. The

community below Dresden Lock and Dam (RM 271.4) on the Illinois River was similar to that in

the upper Des Plaines River and the Kankakee River. These results indicate that members

ofthe

phytoplankton communities in the system receiving warm-water effluents were similar to those

removed from this influence. Although identified as a potential concern in the draft

UAA report,

the UIW studies

of phytoplankton and periphyton clearly show that the system is not dominated

by blue-green algae.

It

is, in fact, populated by the same species assemblage as other similar

river-reservoir navigation channels. Phytoplankton density at Joliet was comparable to the

density observed in Pool 19

ofthe Mississippi River, which is not thermally impacted. This

shows that members

ofthe phytoplankton and zooplankton communities are not impacted on a

long-term basis

by power generation.

F. No Adverse Thermal Effects on Macrophytes

Surveys showed that aquatic macrophytes occur throughout the UIW wherever suitable substrate

occurs (Final Report,

UIW Study, 1995. Chapter 6). Elevated water temperatures seem to be

having no adverse effect on macrophyte stands, either in the general, system-wide context or in

the immediate vicinity

ofpower plant discharges. As the result ofrespiration, oxygen levels

within the confines

of the macrophyte beds may fall to low levels during the night, especially in

the two upper pools. This may limit the value

of such areas as habitat for sensitive fish species

and life stages.

G. No Adverse Thermal Effects on Benthic Macroinvertebrates

The elevated water temperatures below power plant discharges or the generally warmer

conditions that prevail in the

UIW relative to nearby waterways are not adversely affecting

macroinvertebrate composition

or distributions. Habitat condition, as well as sediment quality,

rather than temperature, appear to be the primary controllers

ofbenthic invertebrate community

composition within

the UIW system. (Final Report, UIW Study, 1995. Chapter 7). The

assemblages

of near-field areas at each ofthe generating stations studied generally demonstrated

an overall improvement in community quality relative to areas either upstream

or further

33

---

downstream ofthe discharge, a result likely arising from improvements in flow regime within

the discharge canals themselves. The UIW Study findings directly contradict the draft UAA

report contention that the number and distribution

of bottom organisms decreases as temperature

increases. This might hold true where identical, suitable habitat conditions are present and not

variable, as in the case of the Lower Des Plaines River, where macroinvertebrate habitat

conditions are generally better within the discharge canals

ofthe power plants than elsewhere in

the waterway, despite the sometimes elevated temperature conditions.

It

is also important to

understand that the warmest temperatures occur in the upper to middle portions ofthe water

column, thus not affecting bottom-dwelling benthic macroinvertebrates. In the UIW study, any

taxa that were found to be reduced or eliminated within the near-field areas typically

demonstrated a rapid recovery to the composition and condition

ofthose upstream ofthe

discharges. This suggests that there was no observable cumulative impact ofthermal effluents

on the macroinvertebrate community.

H. Effect on Fisheries

The "Selection ofthe Temperature Standard" and "Critique ofthe Current Secondary Contact

and Indigenous Aquatic Life Standard" sections ofthe draft UAA report have many inaccurate

statements regarding temperature effects on riverine species and ecosystem processes. High and

low temperatures

mayor may not be detrimental to aquatic life that resides in the UIW. There is

not a simple relationship, as noted from many past studies (e.g., Cairns et al. 1973; Cairns et al.

1978; review by the Institute for Environmental Quality 1995). Both low and high temperatures

can increase

AND decrease toxicity due to exposures from other chemical stressors, such as

found in the UIW, and is both species, toxicant type, toxicant concentration and species

dependent. The overly simplistic statement that high temperatures increase toxicity is simply

incorrect. Nitrification is also inhibited by cold temperatures and ammonia is not always

consumed in the upper sediment layers. Nitrification is very sensitive to toxicants, which abound

in the depositional sediments. The UAA consultants AquaNova and Hey and Associates

incorrectly imply that high temperatures are always detrimental by focusing only on negative

thermal impacts and over-generalizing. Both ammonia and ammonium can be toxic but this

is

both species and concentration dependent. For example, the amphipod

Hyalella azteca

is more

sensitive to total ammonia than the un-ionized form. Blue green algae are not a concern in the

UIW due to its high flow. Toxic cyanobacterial blooms have only been noted in pond, lake and

reservoir ecosystems. So, many ofthe "negative" examples used in the draft UAA Report do

not apply to the UIW, yet their presentation implies that they do.

The UIW study data, as well as the results ofMWGen's on-going monitoring, show that the

magnitude, duration and extent

of excess temperature in the Lower Des Plaines River is within

the tolerance range for most ofthe species expected to reside in this waterway, given the existing

physical constraints. Contrary to the implication in the draft UAA Report (October, 2003

revised temperature section, p. 2-93), "[d]irect deaths from excessive temperature beyond the

thermal lethal point" have never been documented in the Lower Des Plaines River. MWGen's

monitoring work (EA, 1997-2002) continues to show that dissolved oxygen levels in the Lower

Des Plaines remain at

or above that needed to support the indigenous aquatic community.

MWGen's long-term fisheries monitoring program (EA, 2002) assessments

offish condition

show that there are no obvious food availability problems in the system. Synergisms between

34

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heat and toxic substances have been shown by Burton'sstudies (1995, 1998, 1999), however,

these studies were conducted under controlled laboratory or in-situ conditions which represented

worst-case exposure conditions. In reality, the heat from MWGen'spower plants does not reach

the areas where most

ofthe sediment-bound contaminants are found.

Exclusion areas--small areas of elevated temperature avoided by sensitive mobile organisms--

will occur

in the immediate discharge vicinities for all ofthe Midwest Generation stations during

the warmer months. The three-dimensional mapping

ofthe thermal plumes (ENSR, 1994, EA,

2003), shows that buoyancy

of warm water limits these exclusion areas to upper water column

layers and that a zone ofpassage at cooler temperatures (of at least 75% ofthe cross-section of

the waterway) remains beneath the surface thermal plume at any time. As part ofthe UIW

Study, fly-over, infra-red imagery was taken

ofthe waterway. (Brady, 1993-1994) These data

also confirm the surficial nature

of the thermal plumes in both the summer and winter periods.

These findings, together with the fact that no fish kills have been reported in or around any

of

Midwest Generation'sstations, support the premise that resident fish species can and do move

temporarily out

ofthermally enhanced areas and into portions ofthe river that are more suited to

their preferred temperature range. Thermal refuges (e.g. tributary mouths) exist throughout the

expanse

ofthe Lower Des Plaines River downstream ofBrandon Road Lock and Dam, and are

also found upstream, although are more limited there due to the physical structure

of the canal in

this area.

The fishery

ofthe UIW is basically a "warm-water" assemblage consistent with the physical

circumstances

ofthe system. Common carp dominate the biomass throughout the system.

Improvements in the diversity of species occur as one moves downstream through the three

navigational pools. The assemblage inhabiting the Dresden Pool, though improved over those

of

the Lockport and Brandon Pools, is still well below expectations. Brandon Road Lock and Dam

is clearly a transition point for the fishery, based primarily on improvements

in habitat

availability relative to the upstream reaches. While it may not be possible to separate the various

stressors to the system to determine which ones are most responsible for the limitations on the

biological potential

ofthe waterway, thermal discharges are not sufficient to account for the lack

of a balanced indigenous fish community in the Lower Des Plaines River. Given the lack of

balance in the Lower Dresden Pool, even ifthermal discharges were to required to comply with

General Use Thermal Standards, there still would not be a balanced indigenous fish community

in the UAA Reach.

The warmer overall conditions

ofthe waterway may also playa beneficial role in protecting the

aquatic ecosystem as a whole, especially in light ofthe recent efforts of state and federal natural

resources agencies to deter the threat

of invasive species to our waterways. The water

temperatures currently encountered in the UAA reach may actually serve to preclude the

migration

of non-native invasive alien species offish, such as the Asian carp, to more sensitive

waterbodies, such as the Great Lakes, which, if unchecked, could have a devastating effect on

Lake Michigan's indigenous aquatic community/sport fishing industry. Midwest Generation has

been working cooperatively with state and federal natural resources agencies to assist

in the

development of plans to control the migration of invasive species in the UAA waterway, using

whatever means are technically and legally available.

35

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I. Temperature Effects on Dissolved Oxygen Levels

For purposes of analyzing dissolved oxygen (D.O.) levels, the waterway can be divided into two

segments: the area above and the area below the Brandon Lock and Dam. Dissolved oxygen

levels vary seasonally in both areas in accordance with the prevailing water temperature regime,

the changing solubilities

of oxygen and with oxygen levels in tributaries and other source waters.

Oxygen concentrations in the Lockport and Brandon Pools are typically below saturation,

periodically dropping below the Illinois Secondary Contact standard

of4.0 ppm. Generally,

higher oxygen levels are observed downstream

ofthe Brandon tailwaters and in the Dresden

Pool. In part, this

is the result ofthe reaeration that occurs at the Brandon Road Dam and

transport through the tailwater area. Dissolved oxygen levels in the Dresden Pool main channel

are generally improved over those in the two upper pools, and are generally

in compliance with

applicable limits. (EA, 1997-2002 Temp/D.O. Study Reports).

It has also been speculated that power plant discharges, by adding an increment

of heat to the

overall waterway, are accelerating the bacterial and chemical decomposition

of organic matter

and the respiration

of aquatic plants, thereby reducing dissolved oxygen levels. While this may

be conceptually correct, the actual reduction is very small, and more importantly, accelerating

decomposition has the overall positive effect

ofreducing levels of organic materials in the

system.

It

is likely that occasional decreases in dissolved oxygen levels in the system are

primarily caused by heavy rainfall events, nutrient introduction and primary productivity cycling

and/or increased boat traffic, rather than the input

of heat from power plants. (EA 2001

Temp./D.O. Study Report, p. 8-11). Illinois

EPA's UAA consultant also has suggested that the

cause

of sporadically low D.O. cycles in the system may be more the result of nutrient

enrichment and photosynthesis, rather than strictly thermal inputs. (Vladimir Novotny --personal

communication. December 13,2001).

At times power plants can also contribute to increasing the level of dissolved oxygen in a

waterway. In the

UAA Reach, the intermittent use of Joliet Station #29's supplemental cooling

towers during warm weather periods contributes additional dissolved oxygen to the waterway.

The total contribution has not been quantified but may more than offset any incremental

decreases in dissolved oxygen perceived to be the result

of power plant operations under high

temperature conditions.

Significantly, the water temperature/dissolved oxygen studies at the I-55 Bridge performed

annually by ComEd/Midwest Generation since 1997 have not shown consistent correlations

between high water temperatures and prolonged adverse levels

of dissolved oxygen.

Supplemental physicochemical monitoring done as part

of Midwest Generation's long-term

fisheries monitoring system also show that dissolved oxygen levels are variable throughout the

waterway during the course

ofthe monitoring period. Typically, D.O. levels are at or above

minimum limits in the various habitats sampled over the course

ofthe summer period. (EA

Upper Illinois Waterway Fisheries Investigation Reports, 2000, 2001, 2002) The observation

that lower D.O. levels in the system are generally limited to a few locations for short periods

of

time indicates that low D.O. is not a widespread problem in the waterway.

36

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Short-term, localized "low" D.O. levels, whatever the cause, should not have any measurable

adverse impacts on the aquatic community. The U.S. EPA Green Book (FWPCA, 1968)

recommends a warm water fisheries one-day acceptable minimum dissolved oxygen

concentration

of 3.0 mg/l, with a 7-day minimum of4.0 mg/I. Dissolved oxygen levels in the

Lower Des Plaines River are generally well above these minimums. The data analysis presented

as part ofthe current UAA Study, as well as the UIW Study results and current monitoring data,

all indicate that dissolved oxygen levels

in the Lower Des Plaines River are more than sufficient

to support the indigenous aquatic community.

Overall, the average D.O. in the waterway

is well above that needed to sustain the indigenous

biological community,

as evidenced by both continuous I-55 monitoring, as well as

measurements taken

as part ofMWGen's long-term fisheries monitoring program. These data

continue to show more than adequate levels

ofD.O. at all ofthe sampling locations in the Lower

Des Plaines River, including the immediate generating station discharge canals, where water

temperatures are the highest.

IX.

UNIQUENESS

OF THE

WATERWAY

The Lower Des Plaines River, along with the Chicago Sanitary and Ship Canal, Cal-Sag Canal

and portions ofthe Chicago River are the only major waterbodies in the State currently

designated

as Secondary Contact and Indigenous Aquatic Life waters. They have held this

designation since its inception in 1974

.. This is due to the unusual and unique character of this

waterway. Its uniqueness creates additional challenges in trying to determine what its overall

potential as a valued State aquatic resource could be in the future.

The unique character

of the UAA Reach makes it difficult to identify a biological reference site

for this portion

ofthe UIW. The UAA Biological Subcommittee had several discussions

regarding the availability, or lack

of availability,ofa biological reference site for the Lower Des

Plaines River UAA Reach. A reference site is needed in order to be able to compare biological

measurements from the Lower Des Plaines River with other physically similar streams

in the

State to determine the overall potential

ofthe system. Several rivers in the same ecoregion have

been proposed for consideration as a reference site by various Subcommittee members and the

IEPA consultants, but none has received the consensus support

ofthe UAA Biological

Subcommittee upon further review. This is because there are no other waterways

in the State

that have the same artificially-controlled flow/level regime, the man-made "shorelines" or the

significant commercial navigationaVstorm water control uses

of the UAA Reach. All ofthese

characteristics must be considered for a proper assessment and comparison

of biological

potential, because they are permanent features ofthe UAA Reach.

Without

an appropriate representative reference stream, a prediction that the UAA Reach can

attain the General Use classification

is highly speculative. In other words, there is no actual

real-life stream that mirrors the UAA Reach to show with a reasonable degree of certainty that

General Use can

be attained. We lack this reasonable basis on which to determine what the

UAA Reach

is capable ofregarding the type ofaquatic life it can support with more stringent

water quality limitations in place. For this reason, the suggestion that a separate use designation

37

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for this particular portion ofthe waterway should be developed based on what it actually has

attained,

or what it might reasonably attain in the future, warrants further review.

x.

CURRENT MONITORING STUDIES OF THE UAA REACH

Midwest Generation continues to perform physical monitoring in the UAAReach, including

temperature monitoring (done year round at each generating station and at the I-55 Bridge), as

well as seasonal temperature/dissolved oxygen monitoring at I-55. Midwest Generation,

working with the Iowa Institute

of Hydraulic Research, also continues to perform thermo-

hydrodynamic modeling

ofthe waterway as part of its on-going compliance commitment. These

models are, by necessity, very customized in nature, due to the unique circumstances present in

the river system. .

The studies conducted on the UIW show the waterway to be populated with aquatic biota

capable

of carrying out their life functions under the constraints ofavailable physical habitat.

The studies also show that some species (e.g. walleye) and organism groups (e.g. redhorses) that

might be expected in a slow-moving river-reservoir system

in the Midwest at this latitude,

though present, are found in reduced numbers.

The important questions here are:

(1)

Is the heat contribution

of Midwest Generation'splants sufficient to raise temperatures to

a range that would exclude expected species, or are the reduced numbers

of such species

a result

of other factors, such as poor habitat?; and

(2)

What temperature limits are reasonable for the protection of organisms one would

reasonably expect to inhabit the waterway?

Although temperature is but one factor among many that the study has shown affects aquatic life,

it is useful to examine the temperature requirements

ofthe biota in relation to existing and

expected future waterway temperatures. The best information on temperatures requirements for

biota is available for fish. The fish community

ofthe Lower Des Plaines River has been

monitored on an ongoing basis for the past twenty-plus years, sponsored by ComEd/Midwest

Generation. The monitoring results continue to show general improvements and/or status quo in

the biological community over time under the existing Secondary Contact thermal water quality

limits. These results indicate that the existing thermal levels in the UAA Reach are not a

significantly limiting factor to the present or future expected biological community.

38

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XI.

ESTABLISIDNG PROTECTIVE THERMAL LIMITS FOR THE BRANDON

POOL AND THE UPPER DRESDEN POOL

A.

Temperature is a Unique Constituent

Temperature has several unique characteristics that need to be considered when determining

appropriate and protective thermal limits. Temperature is non-conservative; excess temperature

dissipates very rapidly to the atmosphere.

It

does not bioaccumulate and under most conditions

it stratifies vertically in the water column, thus allowing for a zone of passage even when surface

temperatures might be excessive. Because temperature "behaves" in a very predictable manner,

thermal models can accurately predict the general spatial distribution ofthermal plumes based on

a few fairly simple input parameters. However, the sudden and unpredictable flow fluctuations

that occur in the Des Plaines River as a result of artificially controlled flow management make

predictions much more difficult than in natural systems.

In

addition to unique physical properties, fish have a well established ability to avoid excessively

warm or cool temperatures (EPRI 1981). Assuming thermal refugia are available, fish will

simply avoid areas that are too hot and return quickly when temperatures are more favorable.

Thus, many species avoid thermal discharges during the middle ofthe summer, but seek out

these areas during cooler periods. This is why many discharge areas are favored "fishing holes"

over much

ofthe year. Avoidance of excessive temperatures is why fish kills are rare during the

summer...the more sensitive species simply leave the area. Thus, from a behavioral perspective,

thermal avoidance is protective.

It

allows fishes to move away from conditions that otherwise

may become lethal.

A distinction needs to be made between short term and long term avoidance (Ohio

EPA 1978).

Short-term avoidance is "the temporary avoidance by a species population caused by the onset of

limiting or unfavorable environmental conditions" (Ohio EPA 1978). Short-term avoidance,

though not rigorously defined, is typically considered to be on the order

of hours or days,

whereas long-term avoidance has been defined as the permanent or prolonged avoidance of an

area (Ohio EPA 1978). Thus, long-term avoidance would be on the order ofweeks or months.

Long-term avoidance is an indicator of appreciable harm (assuming the area avoided is not trivial

in size), whereas, short-term avoidance is not (Ohio EPA 1978). Fisheries studies performed by

EA for over the past 20 years demonstrate that there is short term avoidance

ofthe power plant

discharge canals during the hotter periods ofthe summer, but that fish move back into the

discharge areas once more preferable temperatures resume. There is no evidence that fish

permanently move from the area and do not return.(EA Fisheries Monitoring Studies, various

years).

The AquaNova/Hey Report states (p. 2-99) that "only adult fish are known to escape the impacts

of high temperatures" and that the effect on juvenile fish is "uncertain". This is simply untrue.

U.S. EPA has long acknowledged that juvenile fish can avoid high temperatures. For example,

in their "Gold Book" (U.S.

EPA 1986), the Agency states that "(J)uvenile and adult fish usually

thremoregulate behaviorally

by moving to water having the temperature closest to their thermal

preference" (emphasis added). The EPA report goes on to note that "this response (avoidance)

precludes problems

of heat stress by juvenile and adult fish during the summer." (U.S. EPA

39

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1986). Another interesting aspect of temperature is that the temperatures fish prefer during the

summer are quite close (often within 2-4

0c) to those that are lethal (EPRI 1981).

B.

Brandon Pool Current Conditions

As evidenced by the final meeting minutes ofthe UAA Biological Subcommittee (April 3,

2002), there was a general consensus reached by the biological experts assembled that a General

Use classification is not appropriate for Brandon Pool. This determination was based on existing

limitations (principally poor habitat quality, urbanization, sediment quality and barge traffic)

which either cannot be changed (i.e., the habitat limitations and urbanization) or will not be

changed in the foreseeable future,

ifat all (i.e., sediment quality and barge traffic). Because of

these present and continuing limitations, the aquatic biota in the Brandon Pool will continue to

be dominated by tolerant fishes and macroinvertebrates.

Given the existing and potential biotic community in the Brandon Pool, the present Secondary

Contact thermal water quality standards (WQS) will be protective, whether the area remains

Secondary Contact or is upgraded to a new "modified" use that also accounts for the limitations

inherent in this segment

ofthe UAA Reach.

C.

Dresden Pool

Ifthe use classification for the Upper Dresden Pool (i.e., the area upstream of I-55) remains as

Secondary Contact, then the Secondary Contact thermal standards are and would remain

appropriate to protect that use designation. However, as part ofthe UAA, a potential upgrade of

the use designation to General Use or some other intermediate "modified" use is under review.

Although Midwest Generation submits that a complete analysis

ofthe UAA factors shows that

General Use is not attainable for the UAA Reach, we have included in our review

ofthe thermal

standards whether more restrictive thermal standards would be needed to support any proposed

upgrade in the use designation

ofthe Upper Dresden Pool. As explained further below, this

review concludes that more restrictive thermal standards would not result in any significant

improvement to the aquatic communities

in the Upper Dresden Pool.

To evaluate Upper Dresden Pool thermal alternatives, we applied some

ofthe protocols typically

used as part

ofa 316(a) demonstration under the Clean Water Act

l

.

As with a UAA, a 316(a)

analysis evaluates the physical, chemical and biological conditions

ofthe waterway and

characterizes potential stressors and their impacts. In a 316(a) demonstration, the main focus is

on thermal discharges. The 316(a) process considers what thermal limits are necessary to

support balanced, indigenous aquatic communities.

U.S. EPA has long recognized that it is not practical or necessary to evaluate the thermal

tolerance

of every aquatic species.

It

recommends that a group of Representative Important

Species (RIS) be assessed.

1. A 316(a) demonstration is prepared to support the position that applicable thermal limits are more stringent than necessary to

assure the protection and propagation

of a balanced indigenous community of shellfish, fish, and wildlife in or on the water to

which the discharge is made. The applicant attempts to demonstrate that alternative, less stringent thermal limits, will allow the

protection of existing balanced indigenous communities, or alternatively,.will allow the development ofsuch a community if one

is not present currently. This is the.showing that CornEd successfully made before the Board in the AS96-10 proceeding.

40

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According to U.S. EPA's Technical Guidance Document (U.S. EPA 1977), RIS are those that

are:

1.

Commercially or recreationally valuable;

2.

Threatened or endangered;

3.

Critical to the structure and function ofthe ecological system

I;

4.

Potentially capable of becoming localized nuisance species;

5.

Necessary in the food chain for the well-being of species determined in 1-4; or

6.

Representative ofthe thermal requirements of important species but which

themselves may not be important.

Recognizing that it is not possible or even necessary to study every species at a site in great

detail due to time and resource limitations, U.S. EPA (1977) suggests that 5 to

15 species be

designated as RIS because this range

ofRIS species allows for a representative assessment ofthe

biotic community. Except for threatened and endangered (T&E) species, investigators generally

pick species that are (or are expected to be) fairly common because it is difficult to assess the

status of, or impacts to, species that occur

in low abundance. Also, all other things being equal,

species chosen as RIS should be ones for which thermal tolerance data are available.

Based on existing site-specific information, we compiled thermal tolerance data on the following

Representative Important

SpeCies (RIS) consistent with the U.S. EPA suggestion:

Gamefish

Smallmouth bass

Largemouth bass

Panfish

Green sunfish

Bluegill

Forage Species

Gizzard shad

Emerald shiner

Bluntnose minnow

Benthic Species

Smallmouth buffalo

Channel catfish

Redhorse

Miscellaneous

Species

Freshwater drum

Common carp

D. Justification for the Selection ofRIS:

The selection ofRepresentative Important Species (RIS) for the Lower Des Plaines River is

consistent with accepted methods and guidance. MWGen also considered the inclusion

of a

number

of cool water species, such as walleye, other percids and esocids, as suggested by U.S.

EPA.

However, such cool water species are not appropriate representatives

ofthe potential fish

community in the Lower Des Plaines River. Not only

is the Upper Dresden Pool near the edge

oftheir natural ranges, but there is little or no habitat in the Brandon and Upper Dresden Pools to

support them. For cool water species such as northern pike and yellow perch, which are

examples

ofthe percid species found in some Illinois waters, clear, well-vegetated lakes, pools,

or backwaters are required for them to thrive and particularly to reproduce. Such areas are rare

to nonexistent

in these ,lJIW pools. Therefore, these species will be limited naturally by the lack

of suitable habitat.

-r:-

To evaluate this factor, most investigators include at least one species at each trophic level (e.g. a herbivore, an insectivore, an

omnivore and a top predator).

41

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Even assuming the General Use Thermal Standards applied to the Upper Dresden Pool, neither

good northern pike

nor yellow perch populations would become established. Since, as shown

during

EA's recent habitat survey ofthe entire Dresden Pool (EA. May, 2003), habitats upstream

and downstream

ofI-55 are similar, it follows that these species should have been able to

establish viable populations in the lower Dresden Pool, which is already subject to the General

Use thermal standard. However, data collected over the past nine years (See Table IE), show

that only one yellow perch and one northern pike have been collected from the General Use

portion

ofthe pool. Since populations ofthese two species in lower Dresden Pool are already

protected by the General Use thermal standard, the only logical reason for their extreme rarity in

lower Dresden Pool is lack

of proper habitat or other non-thermal causes. Both species are also

rare in the Upper Marseilles

Pool, which is subject to the General Use thermal water quality

standard, for the same reason (Le. lack

ofhabitat). (See Table IF).

These cool water species are habitat limited in the

UAA Reach and should not be designated as

RIS. U.S. EPA (1977) guidance supports this approach for species at the edge

oftheir range.

The U.S. EPA report stated (p. 36) that "[w]ide-ranging species at the extremes oftheir ranges

would generally not be considered acceptable as 'particularlyvulnerable'

or 'sensitive'

representative species" though they still could be considered important." Here, based not only

on their peripheral nature

but also the obvious habitat limitations, the U.S. EPA guidance does

not support their inclusion in the RIS designation.

Walleye are more thermally tolerant than yellow perch

or northern pike and, as a result, are more

widely distributed in Illinois (Smith 1979). Thus, they were not excluded from the MWGen RIS

list based on being peripheral. However, like the

two species just discussed, they clearly are

habitat limited. Most walleye populations spawn over clear cobble

or rubble areas, but some

populations can spawn in flooded, well-vegetated backwaters. However, except for a small

portion

ofthe Brandon tailwaters, both habitat types are rare in Dresden Pool. Examination of

data from Lower Dresden Pool and Upper Marseilles Pool supports our contention that walleye

are habitat limited.

Nine years of collecting fish has yielded only one walleye from the Lower

Dresden Pool and only one from

the Upper Marseilles Pool (See Tables IE and IF) despite the

fact that General Use thermal standards prevail in both areas. Thus, there is no reason to believe

that walleye would be any more successful in the Upper Dresden Pool than the Lower Dresden

Pool.

Ifwe compare catches of walleye with those of smallmouth bass, a species considered to have

similar thermal tolerance,

or to redhorse, which are likely more thermally sensitive (Reash et al

2000), it is equally clear that walleye numbers in these areas are constrained by something other

than temperature.

For example, Lower Dresden Pool, which yielded only one walleye, produced

477 smallmouth bass and 571 redhorse (all redhorse species combined) during the same period

(See Tables

IE and IF), and upper Marseilles Pool, which also yielded only one walleye, yielded

172 smallmouth bass and 348 redhorse. The only possible interpretation

ofthis data is that

walleye are habitat limited while the other

two species, which have roughly similar thermal

requirements, are not. Given that it is habitat limited, walleye is clearly not an appropriate RIS

for the

UAA Reach.

42

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E.

Temperature Tolerance of RIS

In considering the temperature tolerance of fish, it is important to recognize that their upper

lethal temperature varies directly with acclimation temperature until that species can no longer

be acclimated to any higher temperature (usually referred to as the ultimate upper incipient lethal

temperature). Thus, fish exposed to summertime ambient conditions should be able to withstand

water temperature at or near the upper end

ofthe tolerance range reported for that species. All

the Des Plaines River RIS except for redhorse, have upper temperature tolerances in the mid to

high 30s °C (95

- 100 OF) (Table 2). This indicates that occasional exposure to temperatures in

the mid to high 90s

of should have little effect on these species. The fact that populations of

several RIS are good in the Upper Dresden Pool (EA 2001, 2002) supports this interpretation.

If Secondary Contact thermal standards are adversely affecting RIS, then one would expect that

RIS catch rates would be lower in the Dresden Pool upstream

ofI-55, where the Secondary

. Contact thermal limits apply. Conversely, similar catch rates upstream and downstream ofI-55

would suggest that the Secondary Contact thermal standards in the Upper Dresden Pool have

little

or no influence on the abundance ofRIS. In Table 3, catch rates for all native RIS in the

Dresden Pool (divided into the upstream and downstream

ofI-55 segments) are compared for the

period 1999-2001. Thirty-three upstream vs. downstream comparisons can be made

(11 taxa x 3

years). In

14 ofthe 33 comparisons, there is no appreciable difference between upstream and

downstream

ofI-55 ePE's. In ten of33 comparisons, CPE's are noticeably higher downstream

ofI-55. In nine of33 comparisons, CPE's are noticeably higher upstream ofI-55, where the

Secondary Contact thermal limits apply. Thus, overall there is no clear pattern favoring the

Dresden Pool segment upstream or downstream

ofI-55. On a species-specific basis, there are

some differences. Emerald shiner, green sunfish, channel catfish, and freshwater drum are

generally higher upstream

ofthe I-55 Bridge. Catches of smallmouth bass, gizzard shad,

bluntnose minnow, and smallmouth buffalo show

no clear-cut upstream/downstream pattern.

Redhorse, largemouth bass and especially bluegill

CPE's are higher downstream of I-55.

In

sum, eight

ofthe 11 RIS taxa show either no upstream/downstream preference or have slightly

higher catch rates in the warmer upstream portion

ofthe study area.

Largemouth bass, redhorse, and especially bluegill

CPE's were generally higher in the cooler

waters downstream

ofI-55. However, ofthese three species, only bluegill showed a large

difference in catch rates. Both bluegill and largemouth bass are very thermally tolerant so their

higher catches downstream

ofI-55 are likely not a result of avoiding the area upstream ofI-55.

Given that the abundance of most RIS is not lower upstream ofI-55 and, even when catch rates

are higher downstream

ofI-55, the difference is slight (bluegill being the only exception), it

appears that changing the thermal standard upstream

of I-55 from Secondary Contact to General

Use may result in only a marginal improvement to the fish community.

The only species (group) that would likely be limited

by the Secondary Contact thermal water

quality standards are the redhorses. Little quantitative thermal data are available for redhorse but

the limited data available indicate that its upper lethal limit is about 92

OF and they likely avoid

temperatures in the mid

to high 80s OF (Reash et al 2000). Although the thermal limits

associated with the Secondary Contact use designation would likely be limiting to redhorse, it

43

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appears that other, more important factors, already limit redhorse abundance in the Lower Des

Plaines River.

The Des Plaines River downstream

of I-55 is already designated as General Use. Ifwater

temperature was the principal factor affecting redhorse abundance in the Des Plaines River, then

one would expect that redhorse abundance would be much higher downstream of I-55, which is

already subject to the General Use thermal standards, than upstream ofl-55, where the

Secondary Contact thermal limits apply. Furthermore, in the absence

of other limiting factors,

redhorse abundance

in the Des Plaines River downstream of I-55 would be comparable to that

seen in other similar sized rivers. Redhorse catch rates are higher in the Des Plaines River

downstream

ofl-55 as compared to upstream ofl-55 (Table 4). However, the difference is slight

(about 2 fish/km downstream

ofl-55 compared to about 0.5- fish/ km upstream ofl-55) and

probably not biologically significant. Further, redhorse catches per unit

of effort (CPEs)

downstream

ofl-55 are much lower than they are in the Kankakee River (Table 4). This

indicates that other factors (likely either poor habitat or sediment quality) limit redhorse

abundance

in the Dresden Pool. This being the case, imposing more restrictive thermal

limitations on the river upstream

ofl-55 would likely result in only marginal improvement in

redhorse abundance and little or no improvement in the other RIS.

F.

Is a Balanced, Indigenous Aquatic Community Present?

Another way to determine whether existing or proposed thermal limits are protective is to

determine whether a balanced, indigenous community (BIC) is present; or, if such a community

is not present, are current thermal WQS precluding development

of a Ble. Based on low Index

of Biotic Integrity (illI) scores (calculated using scoring procedures developed in Ohio, (Ohio

EPA 1987), we conclude that a BIC

is not present in the Des Plaines River below the Brandon

Road Lock and Dam (i.e., Upper Dresden Pool). In both 2000 and 2001, mean

illl scores

gradually improved from the mid-teens in Lockport and Brandon Pools to the low 20s in the

Dresden Pool (Figures 2

&

3). A BIC should have illl scores in the low 40s (Ohio EPA 1987).

Thus, even

in the "best" areas (i.e., those downstream of I-55), the Des Plaines River fish

community

is poor, with illI scores not even approaching those that would be expected from a

me.

G.

Are the Secondary Thermal Limits the Cause of the Lack of Balance?

Given that a BIC is not present, it is appropriate to consider whether the lack of a BIC is due to

thermal effects or other causes. Several lines

of evidence suggest that the lack of a BIC is due

primarily to factors other than thermal impacts.

First, IBI scores upstream

ofl-55, where the Secondary Contact thermal WQS apply, are only

marginally lower than in the area downstream of I-55 where the more restrictive General Use

thermal WQS apply (Figures 4-6). This indicates that even

if the observed IBI differences are

due to differences in thermal standards, the net environmental benefit associated with the more

restrictive General Use standards

is minor.

44

---

Second, the mean IBI score in the Joliet Station discharge was comparable to or higher than the

mean score at the location just upstream ofthe station in two ofthe past three years (Figures 4-

6). Ifthe thermal discharge was causing a significant impact, then one would expect that the

impact would be most severe

in the discharge canal (where water temperatures are highest), but

such is not the case.

Third, when slightly better IBI scores do occur

in

the Dresden Pool, they occur in off-channel

areas (e.g., tributary mouth and slough locations) suggesting that,

in general, habitat is more

important than temperature

in determining the quality ofthe aquatic biota. This assertion is

supported by the fact that IBI scores in the Joliet discharge canal (DIS) are comparable to those

at main channel border (MCB) locations both upstream and downstream ofI-55. Also,

temperature measurements

in these off-channel areas can be as high or higher than those in the

main channel, further indicating that temperature is not the driver

in this system (EA 2002).

Fourth, within the upstream I-55 Segment, IBI scores

in the Joliet Station discharge are

comparable to (i.e., within 4 IBI units, Ohio EPA 1987) to those

in other habitats, including

Main Channel Border (MCB), Tributary Mouth (TM), and even Dam Tailwater, a habitat with a

considerably higher QHEI score.

Fifth,

iftemperature was the driving factor with regard to the quality ofthe aquatic biota, then

one would expect that IBI scores downstream

ofthe discharge to be noticeably lower than those

upstream

of it. IBI scores at the first MCB location downstream of the discharge were slightly

lower than at the MCB location upstream ofthe discharge in two ofthree years, however, the

decline is minor (on average about 3 to 4 IBI units, Figures 4

&

6). Even if this small decline is

real, the spatial extent

ofthe decline is small. In 2001, IBI scores immediately upstream and

downstream

ofthe discharge were comparable (Figure 5). Further, the fact that IBI scores in the

discharge itself, where water temperatures are highest, were higher than in areas downstream of

it suggests that the slightly lower scores at the next location downstream (where temperatures

would be lower) may not even be related to the thermal discharge.

In any case, it is reasonable to conclude that whatever thermal impacts there might be are minor,

limited to a small area, and

ofminor consequence compared to other, more limiting factors.

If thermal is not the principal factor accounting for the lack of a BIC and causing a poor biota

throughout the Dresden Pool, then it is reasonable to ask what factor(s) are limiting the biota. As

discussed in greater detail elsewhere in this report, there are several factors that clearly limit the

quality

ofthe biota. The two most severe limiting factors are poor habitat quality and sediment

quality/contamination. Constant barge traffic and urbanization are two likely additional factors,

and, based on QHEI metric scores, siltation is also a likely contributing factor (Note: this refers

to the general negative effects

of siltation in general [e.g., burying of habitats], not the toxic

component

of sediment). His also important to note that ofpossible contributing factors, only

water temperature can be addressed in part by point source controls. Thus, even if General Use

thermal standards were adopted for the Des Plaines River upstream ofI-55, the relevant data

shows that the aquatic biota would not significantly improve because the factors that do

significantly limit the quality

ofthe biota cannot and will not be controlled.

45

---

H.

Would the Upper Dresden Pool Aquatic Biota Improve Significantly if General Use

WQS Were Applied and Would a BIC be Achieved?

Theoretically, the numbers of only a few species would increase in the Upper Dresden Pool, with

redhorse being the group most likely to improve. In reality, however, any improvement is likely

to be negligible because other, more influential, factors limit the quality

ofthe biota. With

regard specifically

to redhorse, this is clearly the case as the abundance of redhorse in Dresden

Pool downstream

of I-55, where General Use thermal WQS already exist, is only marginally

higher than that in the Dresden Pool upstream

ofI-55. (Table 3). Some ofthe other reasons why

meaningful improvement in the Upper Dresden Pool aquatic community

is unlikely include the

following:

(l) No thermally sensitive cold- or cool-water species are present

(2) Other factors, some

of which are irreversible, limit the community

(3)

The community in the Des Plaines River downstream ofthe I-55 Bridge is not

balanced despite General Use WQS (and thermal limits) being in place

(4)

The amount of clean spawning substrate is limited for certain fish species due to

excessive siltation.

Therefore, except for a possible small increase in redhorse abundance, the fish and benthic

communities

ofDresden Pool upstream ofI-55 are not likely to improve significantly even if

General Use thermal standards are imposed. For these same reasons, it is highly unlikely that a

BIC would develop in this area.

The biological community data collected on the Lower Des Plaines River for the past

20+ years

is more reliable and ecologically meaningful.

It

warrants a higher level of credence than

laboratory-derived endpoints that attempt to predict how the biological community would

respond. Good populations will be maintained only

if there is adequate early life history

survival, successful spawning, etc. An examination

ofthe long term data sets shows that those

species tolerant

ofthe extensive limiting conditions that exist in the study area

(e.g.,

gizzard

shad, most centrarchids, various minnows, etc.) are doing quite well, whereas those that are more

sensitive to these limitations (e.g., redhorse and darters) are not. Thus, it is factors other than

temperature

(e.g.,

sedimentation, poor habitat, silty and/or contaminated sediments, etc.) that

determine and limit the Upper Dresden and Brandon fish communities. Temperature plays an

insignificant role.

In

other words, there would be no significant change in these fish populations

even

if General Use thermal standards were applied to the Upper Dresden and Brandon Pools.

Indeed, the results

ofthe recent pool-wide habitat assessment (EA. May, 2003), coupled with the

poor IEI scores throughout Dresden Pool suggest that,

if anything, it is Lower Dresden pool that

is misclassified. Because

ofpoor habit conditions due to impounding and the other factors

discussed previously, the biological data supports a lowering

ofthe use classification ofLower

Dresden Pool and does not support upgrading the use designation

ofthe upper Dresden Pool.

46

---

TABLE 1E.

NUMBER, CPE (No. Ikm), AND RELATIVE ABUNDANCE OF ALL FISH TAXA COLLECTED

ELECTROFISHING FROM LOWER DRESDEN POOL

(between the I-55 bridge and Dresden Lock and Dam) FOR THE PERIOD OF 1994-2002.

LOWER DRESDEN

POOL

SPECIES

#

CPE

-----

%

LONGNOSE GAR

32

0.16

0.079

SHORTNOSE GAR

1

0.01

0.002

UNID GAR

3

0.02

0.007

SKIPJACK HERRING

35

0.18

0.087

GIZZARD SHAD

12,070

62.00

29.881

THREAD FIN SHAD

391

2.01

0.968

GRASS PICKEREL

4

0.02

0.010

NORTHERN PIKE

1

0.01

0.002

CENTRAL STONEROLLER

5

0.03

0.012

GOLDFISH

9

0.05

0.022

GRASS CARP

1

0.01

0.002

COMMON CARP

1,022

5.25

2.530

CARP X GOLDFISH

HYBRID

134

0.69

0.332

BIGHEAD CARP

2

0.01

0.005

GOLDEN SHINER

21

0.11

0.052

PALLID SHINER

3

0.02

0.007

EMERALD SHINER

3,781

19.42

9.360

GHOST SHINER

12

0.06

0.030

STRIPED SHINER

20

0.10

0.050

SPOTTAIL SHINER

347

1. 78

0.859

RED SHINER

2

0.01

0.005

SPOTFIN SHINER

400

2.05

0.990

SAND SHINER

3

0.02

0.007

REDFIN SHINER

1

0.01

0.002

MIMIC SHINER

3

0.02

0.007

CHANNEL SHINER

1

0.01

0.002

BLUNTNOSE MINNOW

2,602

13.37

6.442

FATHEAD MINNOW

1

0.01

0.002

BULLHEAD MINNOW

1,141

5.86

2.825

RIVER CARPSUCKER

141

0.72

0.349

QUILLBACK

90

0.46

0.223

UNID CARPIODES

1

0.01

0.002

WHITE SUCKER

11

0.06

0.027

SMALLMOUTH BUFFALO

363

1. 86

0.899

BIGMOUTH BUFFALO

21

0.11

0.052

BLACK BUFFALO

9

0.05

0.022

SPOTTED SUCKER

4

0.02

0.010

SILVER REDHORSE

28

0.14

0.069

RIVER REDHORSE

6

0.03

0.015

BLACK REDHORSE

1

0.01

0.002

GOLDEN REDHORSE

358

1. 84

0.886

SHORTHEAD REDHORSE

177

0.91

0.438

UNID MOXOSTOMA

1

0.01

0.002

BLACK BULLHEAD

3

0.02

0.007

YELLOW BULLHEAD

47

0.24

0.116

CHANNEL CATFISH

376

1.93

0.931

UNID AMEIURUS

1

0.01

0.002

TADPOLE MADTOM

4

0.02

0.010

FLATHEAD CATFISH

17

0.09

0.042

TROUT-PERCH

1

0.01

0.002

BLACKSTRIPE TOPMINNOW

16

0.08

0.040

BROOK SILVERSIDE

98

0.50

0.243

WHITE PERCH

4

0.02

0.010

WHITE BASS

9

0.05

0.022

YELLOW BASS

8

0.04

0.020

HYBRID MORONE

2

0.01

0.005

UNID MORONE

5

0.03

0.012

ROCK BASS

11

0.06

0.027

47

---

TABLE lE

(cant. )

LOWER DRESDEN POOL

SPECIES

(cant. )

---

#

---

CPE

----

%

GREEN SUNFISH

3,146

16.16

7.788

PUMPKINSEED

26

0.13

0.064

WARMOUTH

5

0.03

0.012

ORANGES POTTED SUNFISH

3,040

15.62

7.526

BLUEGILL

7,271

37.35

18.000

LONGEAR SUNFISH

67

0.34

0.166

REDEAR SUNFISH

1

0.01

0.002

HYBRID SUNFISH

108

0.55

0.267

UNID LEPOMIS

110

0.57

0.272

SMALLMOUTH BASS

477

2.45

1.181

LARGEMOUTH BASS

1,659

8.52

4.107

UNID MICROPTERUS

1

0.01

0.002

WHITE CRAPPIE

15

0.08

0.037

BLACK CRAPPIE

35

0.18

0.087

BANDED DARTER

1

0.01

0.002

YELLOW PERCH

1

0.01

0.002

LOGPERCH

126

0.65

0.312

BLACKS IDE DARTER

1

0.01

0.002

SLENDERHEAD DARTER

3

0.02

0.007

WALLEYE

1

0.01

0.002

FRESHWATER

DRUM

439

2.26

1. 087

TOTAL FISH

40,394

207.50 100.000

48

---

TABLE IF.

NUMBER, CPE (No.

lion),

AND RELATIVE ABUNDANCE OF ALL FISH TAXA COLLECTED

ELECTROFISHING DOWNSTREAM OF DRESDEN LOCK AND DAM

FOR THE PERIOD OF 1994, 1995, AND 1999-2002.

DiS

DRESDEN L&D

SPECIES

LONGNOSE GAR

SHORTNOSE GAR

UNID GAR

SKIPJACK HERRING

GIZZARD

SHAD

THREAD FIN SHAD

GOLDEYE

GRASS PICKEREL

NORTHERN PIKE

GRASS CARP

COMMON CARP

CARP X GOLDFISH HYBRID

GOLDEN SHINER

EMERALD SHINER

GHOST SHINER

STRIPED SHINER

SPOTTAIL SHINER

RED SHINER

SPOT FIN SHINER

SAND SHINER

MIMIC SHINER

SUCKERMOUTH MINNOW

BLUNTNOSE MINNOW

BULLHEAD MINNOW

RIVER CARPSUCKER

QUILLBACK

HIGHFIN CARPSUCKER

UNID CARPIODES

NORTHERN HOG SUCKER

SMALLMOUTH BUFFALO

BIGMOUTH BUFFALO

BLACK BUFFALO

SILVER REDHORSE

RIVER REDHORSE

BLACK REDHORSE

GOLDEN REDHORSE

SHORTHEAD REDHORSE

GREATER REDHORSE

BLACK BULLHEAD

CHANNEL CATFISH

FLATHEAD CATFISH

TROUT-PERCH

MOSQUITOFISH

BROOK SILVERSIDE

WHITE PERCH

WHITE BASS

YELLOW BASS

HYBRID MORONE

UNID MORONE

ROCK BASS

GREEN SUNFISH

PUMPKINSEED

ORANGES POTTED SUNFISH

BLUEGILL

LONGEAR SUNFISH

HYBRID SUNFISH

SMALLMOUTH BASS

LARGEMOUTH BASS

#

18

1

2

23

1,003

55

1

1

3

1

178

2

2

2,565

7

7

50

5

422

36

9

8

265

257

91

69

1

2

7

180

1

1

50

3

2

236

56

1

1

126

4

1

2

24

3

50

7

3

50

2

466

1

11

559

7

2

172

174

CPE

0.41

0.02

0.05

0.52

22.80

1. 25

0.02

0.02

0.07

0.02

4.05

0.05

0'.05

58.30

0.16

0.16

1.14

0.11

9.59

0.82

0.20

0.18

6.02

5.84

2.07

1. 57

0.02

0.05

0.16

4.09

0.02

0.02

1.14

0.07

0.05

5.36

1. 27

0.02

0.02

2.86

0.09

0.02

0.05

0.55

0.07

1.14

0.16

0.07

1.14

0.05

10.59

0.02

0.25

12.70

0.16

0.05

3.91

3.95

%

0.239

0.013

0.027

0.305

13.301

0.729

0.013

0.013

0.040

0.013

2.360

0.027

0.027

34.014

0.093

0.093

0.663

0.066

5.596

0.477

0.119

0.106

3.514

3.408

1.207

0.915

0.013

0.027

0.093

2.387

0.013

0.013

0.663

0.040

0.027

3.130

0.743

0.013

0.013

1.671

0.053

0.013

0.027

0.318

0.040

0.663

0.093

0.040

0.663

0.027

6.180

0.013

0.146

7.413

0.093

0.027

2.281

2.307

49

---

SPECIES

TABLE IF

(cant.)

DiS

DRESDEN L&D

__#__CPE

%_

WHITE CRAPPIE

2

0.05

0.027

BLACK CRAPPIE

8

0.18

0.106

LOG PERCH

36

0.82

0.477

SLENDERHEAD DARTER

1

0.02

0.013

WALLEYE

1

0.02

0.013

FRESHWATER DRUM

207

4.70

2.745

TOTAL FISH

7,541

171.39

100.000

50

---

Ta ble 2

.

UIpper ThermaIT

empera

t

ures 0

fV

anous

.

D

es

PI.

ames

R'

Iver

RIS

Species

Location

Lifestage

Upper Lethal

Reference

(size)

Temp. (oC)

C. carp*

Poland

Juvi

40.6

Horoszewicz 1973

Lake Erie

YOY

39.0

Reutter and Herdendorf 1975,

Reutter and Herdendorf 1976

Canada

YOY&

35.7

Black, E.C. 1953

Juvi

Channel CF

Lake Erie

165

38.0

Reutter and Herdendorf 1975

Reutter and Herdendorf 1976

AK hatchery

44-57

37.8

Allen and Strawn 1967

Lower

158

36.5

Peterson, Sutterlin, and

Susquehanna R,

Metcalf 1979

PA

SC hatchery

50

36

Cheetham, et

aI. 1976

Bluegill

SC cooling ponds

Juvi (27-

41.9-42.8

Holland, W.E., et aI. 1974

58mm)

SC cooling ponds

40-82

38.5-41.4

Holland, W.E., et aI. 1974

mm

WabashR,

IN

49mm

39.0

WAPORA, Inc. 1976

TN

73, 140

37.4-39.2

Cox, D.K. 1974

Lake Erie

168

38.3

Reutter and Herdendorf 1975,

Reutter and Herdendorf 1976

Mississippi River

Juvi

37.3

Banner and Van Arman 1973

VA hatchery

50-100

36.0

Cherry, D.S., et

aI. 1977

Lower

Peterson, Sutterlin, and

Susquehanna R,

52-159

36.0

Metcalf 1979;

PA

Peterson and Schutsky 1979

Lower

Peterson, Sutterlin, and

Susquehanna R,

52-159

35.8

Metcalf 1979;

PA

Peterson and Schutsky 1979

Lake Erie

35.5

Hickman and Dewey 1973

Mississippi River

YOY

35.0

Cvancara, V.A. 1975

Galveston Bay,

35.0

Chung,

K.

1977

TX

Mississippi River

Juvi,

34,33

Hart 1947

adults

Mississippi River

Eggs

33.8

Banner and Van Arman 1973

Mississippi River

YOY

28.5

Cvancara, V.A. 1975,

Cvancara, et

aI. 1977

*

All data (except redhorse data) from Talmage, S. and D. Opresko. 1981. Literature Review: Response ofFish to Thermal Discharges. EPRI

Publication EA-1840. Redhorse data from Reash,

R., G. Seegert, and W. Goodfellow. 2000. Experimentally-derived upper thermal tolerances for

redhorse suckers: revised 316(a) variance conditions at two generating facilities

in Ohio. Env. Sci.

&

Policy VoI3:S191-Sl96.

51

---

T

a

bl

e 2

.

VJpper

Th

erma

IT

empera

t

ures 0 fVanous

D

es

PI'

ames

R"

Iver

RIS

Species

Location

Lifestage

Upper Lethal

Reference

(size)

Temp. (oC)

LMbass

Parpond, SC

Immature

40.0

Smith, M.H. and Scott 1975

Galveston Bay,

37.2

Courtenay, et al. 1973

TX

Mississippi River

YOY

36.2

Cvancara, V.A. 1975

Galveston Bay,

36

Chung,

K.

1977

TX

Mississippi River

YOY

35.6

Cvancara, V.A. 1975

Cvancara, V.A. et al. 1977

Canada Lake

52

g

28.9

Black, B.C. 1953

SM bass

Alabama

YOY

37.0

Wrenn 1980

Lake Erie

151

36.3

Reutter and Herdendorf 1975,

Reutter and Herdendorf 1976

New

&

East R.,

50-100

35.0

Cherry, D.S. et al. 1977

VA

Alabama

Adults

35.0

Wrenn 1980

Green SF

35

Whitford 1970

FWDrum

Mississippi River

YOY

36.0

Cvancara 1975

Lake Erie

180-212

34.0

Reutter and Herdendorf 1975,

Reutter and Herdendorf 1976

Mississippi River

YOY

32.8

Cvancara, V.A. 1975

Cvancara, V.A. et al. 1977

E. shiner

S. Canadian R,

Adults

37.7

Matthews and Maness 1979

OK

Lake Superior

Juvi

35.2

McCormick and Kleiner 1976

Canada

Juvi

30.7

Hart 1947

Gizzard shad

Lake Erie

?

36.5

Hart 1952

Lake Erie

152-167

31.7

Reutter and Herdendorf 1975,

Reutter and Herdendorf 1976

Mississippi

YOY

31.0

Cvancara, V.A. 1975

Mississippi

YOY

28.5

Cvancara, V.A. 1975,

Cvancara, et al. 1977

BNminnow

WabashR, IN

38

WAPORA, Inc. 1971

New

&

East

Rivers, VA

50-100

32

Cherry, et al. 1977

New Yark streams

31.9

Kowalski, et al. 1978

Shorthead

Muskingum R,

Juvi

33.3

Reash et al 2000

RH

OH

SM buffalo

WabashR, IN

31-34

Gammon 1973

(preferred)

Ohio River

22-23

Yoder

&

Gammon 1976

(preferred)

52

---

Table 3. Comparison of RIS Catch Rates (No/km) Upstream and Downstream of 155.

1999

2000

2001

Species

US 155

DS155

US 155

DS155

US 155

DS155

Smallmouth bass

1.2

0.6

0.4

1.1

1.0

0.9

Largemouth bass

7.9

14.0

7.2

13.7

5.4

6.4

Green sunfish

29.7

12.6

24.5

28.9

16.9

7.0

Bluegill

10.6

50.9

19.0

86.4

18.2

33.9

Gizzard shad

32.1

51.0

27.0

62.3

65.1

84.9

Emerald shiner

10.1

3.2

7.7

1.8

11.4

9.2

Bluntnose minnow

8.3

12.1

6.2

26.7

20.9

19.1

Smallmouth buffalo

3.4

3.7

2.4

2.4

2.5

3.2

Channel catfish

3.2

1.9

3.6

2.0

3.5

1.9

Freshwater drum

3.0

2.6

4.6

1.6

3.0

2.4

Redhorse spp.

0.6

1.1

0.9

0.8

0.2

0.7

53

---

Table 4. Kankakee, IIIinois and Des Plaines River Redhorse (all species combined)

Catch Rates

Kankakee River near Braidwood (11 locations)

YEAR

1999

1998

1996

1993

1992

1991

1990

1989

ePE

(No./km)

27.3

17.5

18.1

25.2

11.4

15.6

20.8

21.5

Kankakee River (IDNR data, timed effort converted to effort per 1 km)

Wilmington Dam

YEAR ePE

2000

88.0

I-55

YEAR ePE

2000

104.0

Confluence

YEAR ePE

2000

4.0

IIIinois River Downstream of Dresden Lock and Dam (upper Marseilles pool)

YEAR ePE

1999

8.7

1995

15.3

1994

4.3

IIIinois River Lower Dresden Pool (several locations)

YEAR ePE

1999

0.9

1998

8.6

1997

5.6

1995

13.1

1994

3.3

Des Plaines River: Lower Dresden Pool Downstream I-55

YEAR ePE

1999

1.1

1998

2.4

1997

2.5

1995

2.3

1994

2.5

Des Plaines River: Upper Dresden Pool Upstream I-55

YEAR ePE

1999

0.6

1998

0.7

1997

0.8

1995

0.0

1994

0.3

54

---

Figure 2. Upper Illinois Waterway Mean 181 Scores, 2001.

50

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55

---

Figure 3. Upper Illinois Waterway Mean 181 Scores, 2000.

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56

---

38 to 42 are the NumericallBI Criteria for Ohio EPA's Warmwater Habitat Aquatic Life Use

18

Figure 4. Mean 181 Scores Within the Upstream and Downstream 1-55 Segments,

1999.

50

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48 is the Numerical

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24

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Riv""r 1\1&1""

57

---

38

to 42 are the Numerical lSI Criteria for Ohio EPA's Warmwater Habitat Aquatic Life Use

Figure 5. Mean IBI Scores Within the Upstream and Downstream 1-55 Segments, 2000.

50,-----------------.,--------------------------,

48 is the Numerical lSI Criteria for Ohio EPA's Exceptional Warmwater Habitat Aquatic Life Use

48

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Riv",r Mil",

58

---

Figure 6. Mean IBI Scores Within the Upstream and Downstream 1-55 Segments,

2001.

38 to

42

are the NumericallBI Criteria for Ohio EPA's Warmwater Habitat Aquatic Life Use

50

~---------------...,..--------------------------,

48 is the Numerical

1BI

Criteria for Ohio EPA's Exceptional Warmwater Habitat Aquatic Life Use

~

--------------------------------------l------------------------------------------------------------1

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Riv",r Mil",

59

---

Xll. COSTIBENEFIT ISSUES

A significant question to be answered in the context ofthe current UAA process is: What is the

costlbenefit

of applying tighter limits and/or technological controls to further limit the amount of

heat introduced to the system? The previous section has documented that the environmental

benefit

of lower temperatures in the Lower Des Plaines River would be negligible in the context

ofthe existing and/or permanent physical limitations ofthis waterway. This section serves to

provide general information for the Agency'sconsideration in determining appropriate thermal

water quality limits for the UAA Reach which adequately serve both biological and industrial

uses while not causing unjustified, adverse economic impacts.

We have not attempted here to

assess all

ofthe other economic impacts that would be caused generally ifthe UAA Reach were

upgraded to General Use. That inquiry is beyond the scope

ofthis report.

A.

Compliance with General Use Thermal Water Quality Limits

Based on modeling studies done as part ofthe UIW Study, it is unlikely the Lower Des Plaines

River could meet the General Use thermal criteria even in the absence

of power plant thermal

discharges. (Final Report, UIW Study, 1995. Chapter 3). Applicability

ofthese limitations to a

system which is so heavily influenced by artificially controlled conditions and the effects

of

heavily urbanized surrounding areas is not likely to improve the biological community and is

also not economically reasonable to achieve.

B.

Costs Associated with Technological Controls and/or Operating Restrictions

to Meet More Stringent

Thermal Water Quality Standards

Review ofthe other UAA factors included in this report demonstrates that General Use is not

attainable in the UAA waterway based on one or more

ofthem Having shown that tone of more

ofthe UAA factors is satisfied here, the proper legal conclusion is that the UAA Reach should

not be designated as a General Use waterway. Therefore, MWGen believes that a full socio-

economic impact study under the remaining sixth UAA regulatory factor

is not warranted.

However, at the Agency's request, a preliminary engineering cost estimate on the

operationaVtechnological considerations

of meeting a stricter near-field water quality

temperature limit will be provided by MWGen as part

ofthis UAA effort. If the opportunity is

provided, details regarding this cost estimate can be presented at a future UAA Workgroup

meeting.

60

---

XIII. CURRENT AND FUTURE OPERATIONAL CONSIDERATIONS

A.

SEASONALITY

OF PEAK POWER PRODUCTION

The highest demand for Midwest Generation's product ("electricity") comes concurrently with

the highest ambient air and water temperatures and lowest river flows.

The critical summer

period is when the need for electricity is the greatest. Air conditioning all ofthe commercial

businesses and residential buildings in northern Illinois requires a tremendous amount

of power.

This is in addition to the normal demands on the system: lighting, computer systems, health care

equipment, routine conveniences, etc. During the hottest times

ofthe year, the ambient river

temperatures are also increased, due

to higher air temperatures and solar inputs. The discharges

from

our power plants also contribute to this temperature rise. This creates a situation in which

thermal stress is exerted on the

waterway from both natural and man-made sources, in response

to ambient weather conditions.

Despite this reality, and yet in fact, because

of it, Midwest Generation plants must remain

available

to provide needed power to the citizens and businesses of Northern Illinois (and

beyond) during these periods. Production levels cannot be adjusted/moved to a less sensitive

time

of year, as an industrial manufacturing facility may be able to do. (i.e. Midwest Generation

cannot

"store" electricity made during off-peak seasons to provide for customer demand during

critical

summer periods).

Midwest Generation is very sensitive to potential impacts on the environment. We have a

continuing commitment to remain

in compliance with our permit limitations. We have continued

to take significant steps to reduce effluent temperature levels during critical periods, including

the use

of cooling towers and unit deratings, in order to maintain compliance with all applicable

thermal

water quality standards while optimizing the ability of our stations to continue to

produce needed power. Midwest

Generation's goal is to strike an equitable and protective

balance between the energy needs

ofthe citizens of Illinois and the environmental concerns

associated with

our operations.

B.

USE OF EXISTING COOLING TOWERS

The 24 mechanical draft, once-through cooling towers at Joliet Station #29 were installed on a

completely voluntary basis

by ComEd in 1999. (This installation took place after the current

alternate thermal limits for I-55 were granted,

not as a means to obtain them). Use ofthe towers

serves to mitigate any potential adverse thermal impacts that station operations could have on

either a near-or far-field basis.

The towers are designed to operate on an intermittent basis only,

and do not receive any type

oftreatment for biofouling control, other than drying. Operation of

the towers results in an effective discharge temperature considerably less than the end-of-pipe

value. Based on design criteria, the

use ofthe towers is projected to result in a temperature

decrease

of at least 14 of in the volume of discharge passed through them (approx. 33% ofthe

total design flow

ofthe station, or over 50% ofthe typical condenser flow rate). Based on actual

temperature monitoring data, a comparison

ofthe pre-cooling tower effluent and the post-cooling

tower effluent shows a more typical temperature decrease is approximately 20 of, and can be

higher under elevated tower influent temperature conditions. This results in

an overall effective

61

---

discharge temperature at least 5 of cooler, and more typically 10°F cooler, than the

corresponding condenser discharge temperature.

Station management remains committed to using the cooling towers on an as-needed basis, to

ensure that all applicable thermal limitations continue to be met.

In

2001, the towers were used

for approximately 40 days during the year to maintain thermal compliance.

In

2002, the towers

were used for approximately

55 days.

In

2003 (to-date), the towers were used for a total of

approximately 37 days, primarily to control near-field compliance with the Secondary Contact

thermal limits. While increased use

ofthe cooling towers could possibly reduce the magnitude of

potential temperature limit exceedances that occur within the allowable excursion hours provided

in the Secondary Contact thermal standard, the cooling towers are not capable

of providing the

cooling needed to prevent the frequency

of such elevated temperatures and hence, the

requirement for significant unit deratings remains the same, raising the possibility

of complete

unit shutdowns, to

meet more stringent thermal limits under General Use water quality standards.

C.

CURRENT PLANT DERATINGS

Use ofthe existing Joliet Station cooling towers alone is often not sufficient to control the

thermal discharge from the plant to meet the current Secondary Contact thermal limits under

adverse weather/river flow conditions. Under these situations, units have been and will continue

to be derated (i.e. megawatt load restricted) when compliance conditions warrant. Unfortunately,

this forced loss

of power occurs when it is most needed by the citizens and businesses of

Northern Illinois. The cost ofunplanned, emergency unit deratings to Midwest Generation is

extremely high, in terms

of lost revenue, and can adversely impact system reliability.

Derating is also not necessarily confined to the summer period. There have been several

occasions in the recent past when the Joliet units have needed to reduce load to meet the

applicable thermal limits during December and March!April, when upstream river temperatures

were elevated and/or when abnormally warm weather conditions persisted over several days.

D.

FUTURE COMPLIANCE ALTERNATIVES

Compliance costs are one ofthe factors to be considered under the UAA to evaluate the

economic impact

of any proposed use upgrade. Among the potential economic impacts caused

by upgrading the UAA Reach to General Use are the costs for additional controls/deratings that

would be required to meet these more stringent General Use thermal standards on a near-field

basis for the Joliet and Will County Stations.

In

the AS96-1 0 adjusted standard proceeding, ComEd presented evidence showing that the cost

estimate to derate generating units to comply with the General Use thermal limits at I-55 (seven

miles downstream of the Joliet Station discharge) was in the range of $3.5M to $16M annually

(in 1995 dollars). As further shown below, complying with General Use thermal limits near-

field, even with an allowed mixing zone, would be significantly more costly, and likely is not

possible given the physical and technological constraints to doing so.

62

---

Based on a review of historical river temperature and station operating schedules, and confirmed

by thermal modeling results, neither Will County nor Joliet Station can consistently meet the

General Use thermal water quality standards under their current operational mode. This would

be true for Joliet Station #29 even with all available supplemental cooling towers in operation.

Further, significant unit deratings would be required during non-summer periods should warmer

weather conditions prevail during the period from December through March, when the General

Use limit is 60/63 of. Ambient, upstream temperatures

ofthis magnitude have been observed

during a number

of years at both our Will County and Joliet Stations.

Installation

of additional cooling towers would appear to be the solution of first choice.

However, there are several, serious obstacles that surface upon further analysis.

The installation

of additional supplemental cooling towers for either Joliet or Will County

presents significant technological obstacles. Aside from the significant costs associated with the

equipment, installation and operation/maintenance

of additional cooling towers, there is not

enough physical space at either station to accommodate the number

oftowers that would be

needed to ensure uninterrupted unit operations during critical demand periods.

It

simply is not

feasible to do. The number oftowers that were installed at Joliet #29 in 1999 was chosen based

not simply on historical derating information, but on the physical space available to

accommodate them on-site. The 24 towers installed filled all

ofthe available physical space

along the Joliet Station discharge canal. These towers enable the Joliet Station to maintain

compliance with the applicable thermal limits. They are not sufficient to achieve compliance

with General Use thermal standards without drastically limiting the operating capability

ofthe

Joliet generating units.

To achieve compliance with more stringent thermal standards, significant unit deratings, and

most probably total unit shut-downs, would be required under the critical load demand

conditions typically encountered during hot, dry summers. The potential loss

of electrical power

totals approximately 2500 megawatts ofnormally available generation to the citizens of Northern

Illinois, or the amount required to service approximately 2.5 million homes. These users would

need to find an alternate source

of power. Since Midwest Generation'ssole business is to

generate power for sale to the open market, the loss

ofthis capability, due to a station's inability

to consistently meet tighter thermal limits at normal operating loads, would likely result

in

the

decision to shut down units unable to supply required power during peak demand times. While

there are other sources

of power in the area, these may not be available during critical demand

conditions, due to prior sale commitments or operational problems. The potential result

ofthe

loss ofthis amount ofpower from the grid could, under extreme circumstances, lead to

instability and ultimately rolling brown or black-outs under adverse weather conditions.

63

---

XIV. TEMPERATURE LIMIT PROPOSAL FOR THE BRANDON POOL

Based on the biological information and supporting data presented and/or referenced in this

report, as well as the determination

ofthe UAA Biological Subcommittee (See meeting notes

dated April 3, 2002), the Brandon Pool cannot support a General Use designation. Dissolved

oxygen, bacteria, copper and temperature limits are not currently meeting General Use standards

in this segment

of the waterway, largely due to unregulated and/or non-point source

contributions. Moreover, the physical characteristics

ofthe Brandon Pool will continue to limit

its future potential to support a higher quality aquatic community, as well as any form

offull

body contact recreation. For the above reasons, Midwest Generation submits that the

existing Secondary Contact thermal water quality standards upstream of the Brandon

Road Lock and Dam should be retained. These standards remain adequately protective ofthe

current and expected assemblage of aquatic organisms that inhabit the Brandon Pool, given the

existing physical

and chemical constraints ofthe system and the existing navigational uses.

XV.

TEMPERATURE LIMIT PROPOSAL FOR THE UPPER DRESDEN POOL (From

Brandon Road

Lock and Dam to the I-55 Bridge)

Midwest

Generation's operations are governed by the variable weather conditions and the

artificially controlled

UIW river flow, neither of which is reliably predictable in either the short

or long-term.

Midwest Generation has taken actions to ensure that its stations can continue to

operate during high electrical demand periods, while still meeting all currently applicable

thermal limitations. This compliance strategy involves using actual monitoring data to track

actual

UIW flow and thermal conditions and also employs thermal modeling to try to anticipate

when river conditions will change and require more stringent control

ofthermal discharges.

Midwest Generation remains on diligent and constant watch

ofthe UIW in-stream conditions to

adjust as necessary its unit loads so that compliance with existing thermal standards is

maintained.

The biological and physical monitoring data from the ongoing collection efforts

ofMidwest

Generation persuasively demonstrate that generally, existing thermal conditions in the

UAA

Reach have no significant adverse effects to the types of indigenous aquatic organisms existing

in or expected

to inhabit this waterway, given the existence of other permanent limitations and

human-induced disturbances. In fact, under the prevailing ambient temperatures, there have

been gradual improvements in the fish community over time, as predicted

by this same type of

evidence that was presented to support the IPCB's decision to grant the alternate thermal

standards in the AS96-10 proceeding. All

ofthis has been achieved because the continual input

of heat to the system at Secondary Contact and AS96-1 0 levels does not cause significant

adverse effects to the

UAA Reach.

As such, Midwest Generation submits that continuing compliance with the existing

Secondary Contact limits near-field, and the alternate I-55 thermal limits far-field, as set

forth in the AS 96-10 Board Opinion and Order, has and will continue to adequately

protect the indigenous aquatic community in the entire

VAA

Reach. Actual river

monitoring data for a period of over twenty years and reliable scientific evaluations of that

64

---

data, supports the conclusion that additional or more stringent thermal restrictions are not

likely to result in any substantial improvement in

the biological community of the system.

Modified

Thermal Limits for Upper Dresden Pool:

Under either the existing Secondary Contact or a new use designation, thennal water quality

standards may be modified in order to provide further protection the current and expected

assemblage

of aquatic life that would reside in the Upper Dresden Pool, given appropriate

consideration

ofthe pennanent constraints on the system under the UAA Factors 3, 4 and/or 5.

In an effort to make the thennal water quality standards more reflective ofthe existing seasonal

variability in the Upper Dresden Pool, Midwest Generation proposes that a maximum thennal

standard

of 93 of should apply during the summer months of June through September, with step-

wise monthly

or semi-monthly limits applied during the remainder of the year. Temperature in

the main body

ofthe river, as detennined by the Midwest Generation'sNear-Field Thennal

Compliance Model, shall not exceed the maximum limits

by more than 5 of for more than 5% of

the hours in the 12-month period ending December 31m:. This proposal is also conditioned upon

the allowance

of a mixing zone consistent with Illinois regulations. This seasonal approach is

consistent with the standards set in several other Region 5 states, including Ohio, and is also

reflective

of how the adjusted I-55 thermal standards were developed.

Table 5 shows the proposed maximum thennal limits for the Upper Dresden Pool. The numeric

limits are based on the general seasonal temperature cycle

ofthe waterway and incorporate an

increased margin

ofsafety, beyond that already currently afforded by the Secondary Contact

thennal limits. Compliance with these proposed main river temperature standards can be

documented through the use

ofthe proposed Midwest Generation Near-Field Compliance Model,

previously submitted to Illinois EPA and U.S.

EPA Region 5 for review in 2001. (A copy this

submittal is attached as Appendix 4.)

Midwest Generation has proposed this alternate temperature limitation for the Upper Dresden

Pool in an effort to assist the Agency in the development

of appropriate water quality limitations

for this transitional waterway that are reflective

of both the improvements and limitations

inherent to the

Lower Des Plaines River.

Under this proposal, water temperature limits would be gradually lowered over the Fall and

Winter periods, and increased in the Spring period, in correspondence with the current modified

thennal regime ofthe waterway. The seasonal cycle to be approximated by the step-wise

progression

of monthly or semi-monthly temperature limitations would be more reflective of the

ambient conditions encountered and would also be complementary to the existing adjusted

thennal standards at the I-55 Bridge. This approach is appropriate because the Upper Dresden

Pool

is basically a "transition zone" from Secondary Contact to General Use designated waters.

These proposed modifications to the Upper Dresden Pool thermal limits could be implemented

as part

of an overall sub-classification ofthe use designation for the Upper Dresden Pool.

Alternatively, it may be accomplished by a site-specific classification for the Upper Dresden

Pool with water quality

standar~s

that reflect the existing conditions in that segment ofthe UAA

65

---

Reach. More stringent thermal water quality limitations than those proposed above will only

create significantly more burdensome and costly compliance requirements for Midwest

.

Generation stations that are not economically sound or environmentally beneficial for this

particular waterway. Such unnecessary restrictions also threaten

to impose additional hardships

on the general public due to the potential loss

of existing levels of electrical power at competitive

prices when it

is most needed.

66

---

Table 5: Proposed Modified Thermal Limits for the Upper Dresden Pool

(Brandon Road Lock and Dam down to the I-55 Bridge):

Jan 1-31

Feb 1-29

Mar 1-15 Mar 16-31 Apr 1-15 Apr 16-30 May 1-15

May 16-31 Jun 1-30 Ju1I-31

Aug 1-31 Sept 1-30 Oct 1-31 Nov 1-30

Dec 1-31

72

77

82

82

90

90

92

93

93

93

93

93

92

90

82

Maximum temperature in the main body of the river, as determined by the Midwest Generation'sNear-Field Thermal Compliance

Model, shall not exceed the maximum limits listed above by more than 5

of for more than 5% of the hours in the 12 month period

ending December

3l~.

This temperature limits proposal is also conditioned upon the allowance of a mixing zone consistent with

Illinois regulations.

67

---

XVI. SUMMARY AND CONCLUSIONS

There is an abundance of data demonstrating that conditions in the UAA Reach are, and will

remain, strongly limiting for aquatic life. The UIW Study results show that the lack

of diversity

and quality

of physical habitats in the UAA Reach are the primary reasons why a full aquatic life

use is not attainable. The existence

offme, silty sediments in the limited habitat areas that do

exist in the UAA Reach, along with chemical contamination present in certain sediments, are

also important, contributing factors that prevent the attainment

of the "fishable/swimmable" uses

represented by the General Use classification. Even

if the physical habitat conditions could be

improved significantly, the predominant uses

ofthe waterway, namely barge transport and

conveyance

oftreated effluents and storm water away from the Metropolitan Chicago area,

would still have significant adverse effects on the biological community. Artificially controlled,

variable flows and pool levels to accommodate navigational needs present a condition which is

considerably altered from what would be found in a natural waterway. As such, these constraints

are irreversible and cannot practically be mitigated. Similarly, there is no cost-effective or

practical solution to the residual chemical sediment contamination that exists throughout the

system, or the fact that the system will continue to be dominated by fine-grained sediment in the

future, limiting its ability to support a more diverse biological community. In addition to

continuing siltation, the impounding effect caused by the Brandon and Dresden Lock and Dams

has permanently degraded the riverine habitat by the elimination

of riffles and fast water areas.

And finally, there is no legal authority to require the reduction

of the non-point source run-off

that enters the UAA Reach in significant amounts and aggravates further the chemical sediment

contamination.

Ambient water temperatures (main channel temperatures without power plant contributions)

approximate the regional norm for warm-water streams in spring, summer, and fall. Winter

ambient water temperatures tend to be elevated slightly above regional expectations due to the

large inputs

ofwater from POTWs. The maximum summer temperature rise above background

when the five Midwest Generation stations (Fisk, Crawford, Will County, Joliet #9, and Joliet

#29) are operating at normal load schedules (all sources considered)

is about 8 OF at I-55, while

compared to the General Use standard'sprohibition

of no more than a 5 OF rise above "natural"

conditions. However, under winter conditions, the maximum temperature rise through the

system is about 12 OF above background (assuming all plants are operating at normal load

schedules, which is often not the case during the winter period when unit maintenance outages

occur). Small areas around the discharges from the individual power stations may be warmer.

There is substantial temperature variability outside the main channel in the UAA Reach that is

unrelated to power plant operations. Side channel, slough, and backwater habitats are often

warmer than mid-channel areas in mid-summer (due to solar heating) and colder in winter.

Complex physical and chemical interactions occur between the elevated temperatures and the

dissolved oxygen cycle and the system dynamics

of organic and inorganic toxicants. However,

in no case is temperature the primary factory that constrains the establishment

of more favorable

physical and/or chemical conditions for aquatic life. In other words, even

ifthe thermal

standards were upgraded to General Use, the "fishable, swimmable" standards

ofthe Clean

Water Act would not be attained.

68

---

The extensive biological studies done to date continue to support the conclusion that, due to both

physical and chemical limitations, the UIW as a whole, and the UAA Reach specifically, remains

incapable

of sustaining a high quality aquatic biota representative of the region and oftrue

General Use waterbodies. At the same time, the studies provide no indication that water

temperature is, in any way, significantly constraining the establishment of a unique biota suited

to the physical and chemical limitations

of the system. Species that find physical circumstances

that suit their natural history appear to flourish within the limits set by sediment chemical

contamination and physical constraints and navigational use

ofthe UAA Reach. Species tolerant

ofthe physical and chemical limitations that define the system are typically tolerant ofthe

elevated temperature regime

as well. The discharge temperatures allowed by the applicable

Secondary Contact standards, including the AS96-1

0

limits, clearly do not further limit the

representative fish species and other aquatic life present

in the UAA Reach.

Moreover, conditions for aquatic life

in the UAA reach are not expected to substantially improve

in the foreseeable future, even if point source dischargers are required to reduce current loadings

to the water body. The "recovery"

of a degraded system generally depends on a sequence of

improvements. Ofprimary importance is a substantive improvement in the physical, as well as

the chemical condition ofthe waters. Suitable water clarity, dissolved oxygen content, and

nutrient loadings associated with an absence or low levels

of chemical contaminants such as

trace metals, ammonia, herbicides, pesticides, petroleum products and other materials associated

with agriculture, industrial processes, or urbanization are paramount. A diversity

of

uncontaminated physical habitats suitable to the native regional assemblage of aquatic life is also

a necessary component

of overall ecological integrity. Given a physical and chemical

environment that meets minimal requirements for life, there must be a diversity of seed

organisms available to recolonize a formerly degraded area. Finally, the physical/chemical

environment must be sufficiently favorable to permit the recolonization process to proceed.

In the UAA Reach, the water quality has greatly improved since the adoption and application

of

the Secondary Contact water quality standards. These improvements stem from additional

treatment and control implemented by public and private waste treatment facilities that discharge

to the UAA Reach. Moreover, similar improvements have realized in the tributary drainages.

There also is a suitably diverse assemblage

of seed organisms available to colonize the UAA

Reach. Nonetheless, irreversible obstacles still remain to the establishment

of a higher quality

biota. These obstacles include: (i) the general lack

ofhabitat diversity and lack of balance

among habitat types in the UAA Reach

(e.g.

except for the Brandon tailwaters, riffles are absent

in the UAA study area); (ii), physical characteristics ofthe sediments; and (iii) contaminated

sediments and physical habitat disturbances associated with barge traffic and water level

fluctuations.

The resurgence ofmacrophyte beds, proliferation

of more tolerant forms and continuous input of

immigrants of more sensitive species from the tributaries to the UAA Reach serve to mask the

prevailing level

of physical and sediment-based chemical degradation that still exits.

Colonization by more highly tolerant species and the ability

ofmore sensitive immigrant

organisms to survive in the system may provide some optimism which would lead to the

misassumption that these species would be capable

of carrying out their full life histories in the

69

---

UAA reach. However, there is little prospect of establishing a true resident biota of more

sensitive native species similar

to those inhabiting the higher quality tributaries that feed the

system, such

as the Kankakee River. Sufficient physical habitat to make this possible is simply

not present in the UAA Reach. Moreover, the limited habitat that does exist is further

constrained by the navigational traffic and

the constant flow manipulations and alterations

required

to maintain this protected use in the UAA Reach.

The limiting factors in the UAA Reach are clearly and consistently the physical habitat and

sediment quality limitations that characterize this system. These factors will remain unchanged

for

the foreseeable future. Each ofthese factors alone satisfy the requirements of the UAA

analysis under the Clean Water Act regulations for maintaining the current use designation ofthe

UAA Reach, or developing an alternate use designation that reflects the constraints present in the

waterway. Clearly, the weight

ofthe biological and physical evidence here supports the

conclusion

that General Use is not attainable for the UAA Reach, within the meaning of 40 CFR

131.10(g).

This report also has provided actual monitoring data and pertinent reference information to

demonstrate that the thermal levels in the UAA Reach have not and cannot improve to those

required

under the General Use standards without a significant technical and financial burden to

MWGen. To propose such a use upgrade, and the corresponding thermal water quality standards

required

by General Use, would likely result in a serious loss of electrical capacity to service the

needs

of Illinois industrial and residential users while not reaping any significant environmental

benefits

to the UAA Reach. Twenty-plus years of actual river monitoring data show that the

present thermal regime

ofthe Lower Des Plaines River has not negatively impacted the

biological

community that resides in the system. Other more important factors, such as habitat

limitations, sediment quality and flow alterations/commercial navigation have far more influence

on the overall assemblage of species capable of residing in the waterway both now and in the

future.

In

addition, there is still a consumption advisory in effect for certain species of fish

present in the

UAA Reach--this alone should preclude the area from being designated as full

General Use.

All

ofthe above unalterable conditions and conditions that cannot be modified sufficiently

satisfy

one or more ofthe UAA six regulatory factors to allow for an alternate use designation

for this industrialized urban waterway which

would be commensurate with its permanently

altered character. Accordingly, the Illinois

EPA may elect to preserve the improvements in

chemical

water quality that have been realized in the UAA Reach by creating a new use

classification

or sub-classification that incorporates the chemical levels that are being attained by

the

UAA Reach. Ohio's more specific and refined use classification system is one approach that

can serve as guidance to the Illinois EPA in crafting an alternative use designation. Better and

more refined use designations, with correspondingly differentiated water quality standards, may

help recognize the

water quality improvements in the UAA Reach. As it currently stands, the

Illinois use classification system is not differentiated sufficiently to acknowledge any use levels

that fall between Secondary Contact and General Use. .

The UAA study reach, as a whole, will

not

meet the criteria for a full General Use waterway. Further, as U.S. EPA's UAA guidance

states, primary contact recreation, one

ofthe requirements of a General Use classification, is

also a significant concern for the

UAA Reach. Navigational traffic, as well as widespread

70

---

bacteriological concerns, threaten the safety ofpublic recreation in the waters ofthe Lower Des

Plaines River. Several deaths and near-misses have occurred

in recent years, even with the

current Secondary Contact designation in place. Further mishaps and/or potential tragedies are

more likely to occur

ifthe State deems the UAA Reach suitable for full body contact recreation.

Absent some further refinement

of the Illinois use classification system, the current Secondary

Contact designated use is the only use designation attainable, as shown by the physical, sediment

chemistry/character and biological data relating to the UAA Reach.

71

---

PAGE INTENTIONALLY LEFT BLANK

72

---

APPENDIX 1

Use

Attainability Analysis (UAA) Factors

A Use Attainability Analysis (UAA) consists of six factors that are to be considered in

detennining whether the fishable/swimmable goals

ofthe Clean Water Act (CWA) may be

attainable for a particular water body. (Ref: 40

CPR

Section 131.1 O(g). These factors must be

looked at holistically for the waterway, and not segmented for each particular aspect

ofthe

system, as the draft UAA report has done. Ecological integrity is the summation of all factors

which influence the ability

of organisms to carry out their full life cycles in a given waterway.

Based on the chemical, physical and biological data available for the waterway, the six factors

are outlined below, along with a determination

oftheir applicability to the Lower Des Plaines

RiverUAA:

1.

Naturally occurring pollutant concentration prevent the attainment ofthe use;

»>Potentially applicable if ammonia is considered a naturally occurring pollutant.

2.

Natural, ephemeral, intennittent or low flow conditions or water levels prevent the

attainment

ofthe use, unless these conditions may be compensated for by the discharge of

sufficient volume of effluent discharges without violating State water conservation requirements

to enable uses to be met;

»>Applicable to UAA Reach. See discussion in Paragraph 4 below regarding effect of

low flow conditions and water levels.

3.

Human-caused conditions or sources of pollution prevent the attainment ofthe use and

cannot be remedied or would cause more environmental damage to correct than to leave in place;

»>Applicable to UAA Reach.

Widespread, historic sediment contamination (the result ofhuman activities), as well as

artificially-controlled flow manipulations and barge traffic disturbances affect the entire

length ofthe UAA reach, and beyond. Barge traffic has been shown to be lethal to fish.

Also, there has been no proposal made to remediate the existing sediment contamination

problem and a means to prevent future sediment contamination from non-point sources is

unknown. The impounded nature

ofthe waterway will continue to result in the

deposition

of fine-grained, silty sediments (contaminated or not), which are not

conducive to the development

ofhigher quality fish and macroinvertebrate habitat. As

water-borne commerce, transportation and industrial uses are protected uses under the

CWA, it is unlikely that these activities will cease in the foreseeable future. As such, the

waterway will continue to be dominated by upstream POTW and industrial effluents,

artificial flow control, channelization and barge traffic effects.

73

---

APPENDIXl

Use Attainability Analysis

(VAA)

Factors

4.

Dams, diversions, or other types of hydrologic modifications preclude the attainment of

use, and it is not feasible to restore the water body to its original condition or to operate such

modification in a way that would result

in attainment ofthe use;

»>Applicable to the UAA Reach.

The entire Upper Illinois Waterway (UIW), including the UAA reach,

is basically a series

of pools separated by locks and dams. Flow in the system is controlled entirely by

diversions from Lake Michigan, effluents from large POTWs, and level manipulation to

accommodate barge traffic. Besides their hydraulic influence, these dams greatly affect

habitat quality by eliminating riffles, causing silty sediment deposition and reducing

current speed, etc.

Flow rates are sporadic in nature and vary widely

in magnitude on any given day. Flow .

patterns do not follow any natural, seasonal cycle and cannot be forecast with any

measure

ofaccuracy due to their completely artificial nature.

5.

Physical conditions related to the natural features ofthe water body, such as the lack of

proper substrate, cover, flow, depth, pools, riffles, and the like, unrelated to water quality,

preclude attainment of aquatic life protection uses; or

»>Applicable to the UAA Reach.

Limitations on available, suitable habitat in the system

is the primary constraint which

prevents further substantive improvements in the indigenous aquatic community. What

habitats do exist are also continually disturbed by barge traffic and artificially controlled

river flows and levels. There

is little or no shoreline cover, fast water areas, riffles or

other physical features needed for more desirable fish species to establish viable

populations in this portion

ofthe Lower Des Plaines River. The species that do exist and

actually thrive

in

this system are those whose life history characteristics are better suited

to the physical characteristics and conditions

ofthe waterway.

6.

Controls more stringent than those required by Section 301(b)(I)(A) and (B) and 306 of

the CWA would result

in

substantial and widespread economic and social impact.

»Applicable to the UAA Reach.

The cost to install and operate supplemental cooling for the three Midwest Generation

Stations situated along this waterway to meet General Use thermal limitations would

constitute a significant economic hardship on the company (assuming that installation is

74

---

even feasible, due to physical space constraints at the sites). These costs would not be

offset

by any comparable significant environmental benefit, and would, conversely,

create a serious and potentially dangerous situation in which the power supply of

northern Illinois citizens could be severely jeopardized in

tim~s

of greatest demand,

because the Joliet #9, Joliet #29 and Will County Stations would be forced to shut down

to meet the tighter General Use thermal water quality limits. The citizens

of Illinois

would suffer, and the aquatic community

ofthe Lower Des Plaines would likely see no

measurable or meaningful improvement.

75

---

APPENDIX 2

Executive

Summary ofUIW Study, Results and Conclusions

The UIW Investigation was initiated

in late 1991 with an invitation to Illinois and Federal

regulatory and water management agencies, certain public interest groups, and other water-users

to participate. In response to this solicitation, a multi-institutional group - the Upper Illinois

Waterway Task Force - was formed and charged with the design and oversight

of studies that

would clarify the current status

ofthe waterway and aid in predicting future conditions. CornEd,

in tum, committed to conduct the requisite studies deemed necessary by the Task Force and

utilize this technical information base to develop recommendations for alternative thermal

standards applicable to its power plants.

The investigation included a broad base

of ecological studies ofthe waterway relevant to

evaluating the aquatic ecosystem.

It

included studies of available habitats, biota that would be

expected to be present in these habitats, levels ofwater and sediment contamination, chemical

risk screening, surface thermal imagery

ofthe entire waterway as well as in the immediate

vicinities

ofthe power stations, 3-dimensional reconstructions ofthe thermal plumes for each

power station to evaluate zones of passage around the warmest parts, mathematical thermal

modeling

ofthe entire geographic reach considering all other relevant features affecting water

temperature (including calibration using actual field measurements), and a 40+ year

climatological reconstruction to estimate water temperatures under all historically known

combinations

of ambient weather and plant operating conditions. It included a thorough

literature review

of previous UIW studies, including contaminants in fish tissues.

It

also

included literature reviews on effects

of temperature on fish, interactions of temperature and

chemicals of freshwater biota, and effects ofturbidity and barge traffic on aquatic ecosystems.

These studies, in combination with the biological monitoring

of phytoplankton/periphyton,

macrophytes, benthic invertebrates, ichthyoplankton, fish, and fish diseases comprise the

most thorough study of this portion of the UIW ever conducted.

The studies and surveys performed clearly demonstrate that conditions in the waterway

remain limiting for aquatic life. Lack of diversity and stability ofphysical habitats clearly are

limiting factors, as are the pervasive chemical contamination in sediments and occasional

depressed dissolved oxygen levels. The limitations are mostly severe in the upper pools.

Prospects for improving physical habitat conditions are limited and tend to conflict with the

predominant uses

ofthe waterway, namely barge transport and conveyance oftreated point and

non-point source discharges. Similarly, there are no obvious practical and economical short-term

solutions to the residual chemical contamination

in sediments that persist throughout the system.

The biological studies conducted under the UIW Task Force's direction support the

conclusion that, due to physical and chemical limitations, the UIW remains incapable of

sustaining a high quality aquatic biota representative of the region. At the same time, the

studies provide no indication that the contribution to higher water temperature caused by

power

plant operation is constraining the establishment of aquatic biota suited to the

physical and chemical limitations ofthe system. Species that find physical circumstances that

suit their natural history appear to flourish within the limits set by both chemical contamination

76

---

APPENDIX 2

and limited habitat. Species tolerant of the physical and chemical limitations that define the

system are typically tolerant

ofthe elevated temperature regime as well.

In short, operation

of ComEd's (now Midwest Generation's) power plants does not interfere with

maintaining a reasonably balanced indigenous community

of aquatic organisms in the UIW

consistent with its limited physical habitat, abnormal thermal pattern even in the absence

of

power stations, and history of chemical contamination that remains in sediments.

Based on the results

of these studies, alternative thermal limitations for the I-55 Bridge were

developed and submitted to the Illinois Pollution Control Board in the spring

of 1996. The

Board approved the proposed standards on October 3, 1996. The NPDES permits were modified

to include the standards by February, 1997.

It

is important to note that while alternate

thermal limitations were approved for I-55 based on the study results, the supporting

information contained in

the mw study reports also confirms that the Secondary Contact

thermal limits remain generally supportive of the existing indigenous aquatic community in

the upstream reaches, especially given the other permanent limitations in the system.

Midwest Generation continues to obtain information about the waterway by conducting focused

studies on particular areas

of concern, including potential effects on the fisheries community and

temperature/dissolved oxygen interactions. All recent data suggest that temperature

is not a

significant contributor to the current biological integrity

ofthe system. A reassessment ofthe

conditions in the waterway will be made as conditions warrant.

77

---

APPENDIX 2

Executive Summaries from All Individual

Upper Illinois Waterway Studies

(included with original January 24, 2003 report--electronic copies not available)

78

---

APPENDIX 3

List

of Individual Biological, Chemical and Physical Study Reports

Associated with the Upper Illinois Waterway, 1990 to present

LITERATURE REVIEW

•

EA Compilation/Annotation

of Physical, Chemical

&

Biological Data Pertaining to CSSC,

Lower Des Plaines

&

UIW 1980 - 1991

- Main Report

&

Appendices - (July 1992)

•

Reviews

of Literature Concerning:

- Effects

of Temp. on fish

- Effects

of Freshwater Biota from Interactions of Temperature and Chemicals

- Effects

of Turbidity and Barge Traffic on Aquatic Ecosystems (Dec. 18, 1995)

PHYSICAL/CHEMICAL

•

ENSR Physical-Chemical Study

ofUIW - Summer '93 - Spring '94

•

ENSR D.O./Temp. Monitoring

@

I-55 (1995)

•

EA D.O./Temp. Monitoring

@

I-55 (1997)

•

EA D.O./Temp. Monitoring @ I-55 (1998)

•

EA D.O./Temp. Monitoring

@

I-55 (1999)

•

EA D.O./Temp. Monitoring

@

I-55 (2000)

•

EA D.O./Temp. Monitoring

@

I-55 (2001)

•

EA D.O./Temp. Monitoring

@

I-55 (2002)

•

EA D.O./Temp. Monitoring @ I-55 (2003)--In progress

• Appendix A - Summary

of Physico-chemical Measurements Collected by Municipal

&

Industrial Dischargers within CornEd'sArea of Concern (1993)

(reference copy only)

•

Aerial Imagery

of Surface Temps using Infrared (IR) Imagery

- Summer 1993

.

- Winter 1994

• Thermo-Hydrodynamic Model

ofthe Chicago Sanitary

&

Ship Canal and the Lower Des

Plaines River (Dec. 1994)

(volumes 1

&

2)

•

Fly-Over Photos (Natural

&

IR) (multiple years throughout study period)

•

UIW Report on Estimation

of Water Temperature Exceedance Probabilities in the UIW using

Thermo-Hydrodynamic Modeling (Jan. 1996)

•

LMS UIW Chemical Risk Screening (Jan. 1996)

(Main Report

&

Appendices A - P)

•

UIW 1994 - 1995 Sediment Contamination Assessment, G. Allen Burton Dec. 18, 1995

79

---

APPENDIX 3

List Qf Individual Biological, Chemical and Physical Study Reports

Associated with the Upper Illinois Waterway, 1990 to present

PHYSICAL/CHEMICAL (cont).

•

Continuous In-Situ Monitoring and Thermal Effect Characterization Tasks - Final Report

June 18, 1998 (July 1997 - March 1998)

•

Continuous In-Situ Monitoring and Thermal Effect Characterization Tasks - Final Report

March

11, 1999 (July 1998 - October 1998)

•

Habitat Evaluation

ofthe Dresden Pool (May, 2003--unpublished), performed by EA

Engineering, Science and Technology for Midwest Generation.

BIOLOGICAL

•

Des Plaines River Long-Term Monitoring Program: Aquatic Biology Section Technical

Report Phase I 1986 (6)

•

Des Plaines River Long-Term Monitoring Program: Aquatic Biology Section Technical

Report Phase II (87/04)

•

Des Plaines River Long-Term Monitoring Program: Vegetation Analyses and Habitat

Characterization (88/5)

•

Des Plaines River Long-Term Monitoring Program

-- Vegetation Analyses and Habitat

Characterization (July 1992)

•

1993 Phytoplankton Survey (March 1994)

•

Aquatic Macroinvertebrates within the Upper Illinois Waterway 1992-1993 Report (Feb. 2,

1994)

•

1993 Benthic Macroinvertebrate Investigation and Habitat Assessment

(RM. 272-323) (Feb.

2, 1994)

•

UIW 1994 Benthic Macroinvertebrate Investigation and Habitat Assessment (March 2, 1995)

•

1994 Aquatic Macrophyte Investigation and Habitat Assessment (Feb. 21, 1995)

•

1995 Aquatic Macrophyte Investigation and Habitat Assessment (Jan. 5, 1996)

•

Winter Fisheries Survey on the Des Plaines River 1992 (May 1992)

•

Lower Des Plaines River Aquatic Monitoring - Final Report 1992 (Jun 1993)

•

Winter Fisheries Studies in the UIW 1993 (Oct. 1993)

•

Spring Spawning Survey in the UIW 1993 (Oct. 1993)

80

---

APPENDIX 3

List oflndividual Biological, Chemical and Physical Study Reports

Associated with the Upper Illinois Waterway, 1990 to present

BIOLOGICAL (cont).

•

1994 Winter Fisheries Survey (July 1994)

•

1994 Ichthyoplankton Investigation (UIW) (April 1995)

•

UIW 1993 Fisheries Investigation (March, 1994)

(Report

&

Appendix)

•

UIW 1994 Fisheries Investigation (March, 1995)

(Report

&

Appendix)

•

UIW 1995 Fisheries Investigation (Dec., 1996)

(Report

&

Appendix)

•

UIW 1997 Fisheries Investigation (Feb. 1998)

•

UIW 1998 Fisheries Investigation (April 1999)

•

UIW 1999 Fisheries Investigation (May, 2000)

•

UIW 2000 Fisheries Investigation (March, 2001)

•

UIW 2001 Fisheries Investigation (April, 2002)

•

UIW 2002 Fisheries Investigation (May, 2003)

•

UIW 2003 Fisheries Investigation (In Progress)

uiwsfudies.doc

81

---

APPENDIX 4

Joliet 29 Near-Field Thermal Compliance Model

1.0 Introduction

This model calculates a "fully-mixed" receiving water temperature immediately downstream

of

the Joliet 29 condenser cooling water discharge. Compliance with the Secondary Contact

temperature standards specified in the Joliet Station 29 NPDES permit is determined based on

the output

of this model. (Note: A similar model has also been developed for Joliet 9, but does

not include operation

ofthe supplemental cooling towers in its calculations).

The model determines the fully-mixed receiving water temperature by calculating a weighted

average temperature

ofthe receiving stream, after mixing with the station's condenser cooling

water discharge, based on the effective temperature and flow

ofthe condenser cooling water

discharge and the temperature and flow

ofthe receiving stream. This approach is patterned after

the general mass balance procedure for conservative substances outlined in IEPA's

Illinois

Strategy

for Point Source Waste/oad Allocation,

January 17, 1991.

2.0 Thermal Balance Procedure for Determination

ofEffective Discharge Temperature

The effective discharge temperature input for the model is determined by consideration

of

condenser cooling water flow, condenser cooling water discharge temperature, cooling tower

flow, and cooling tower discharge temperature. When the cooling towers are not

in operation,

the effective discharge temperature is equal to the condenser cooling water discharge

temperature. The basic thermal balance equation for determination ofthe effective discharge

temperature is:

T

EF

= Tcw(Qcw - QT)

+

TTQT

Qcw

Description

Calculated effective condenser cooling water discharge temperature after mixing

with cooling tower discharge, in degrees F.

T

cw

Qcw

QT

Actual condenser cooling water discharge temperature in degrees F. Temperature is

continuously monitored by Bailey and Endeco systems at head of discharge canal.

Condenser cooling water flow in cubic feet per second (cfs). Flow is based on the

number

of circulating water pumps on at the time in question. Each ofthe four

circulating water pumps is rated at 230,000 gpm (512.5 cfs).

Flow

of condenser cooling water routed through the cooling towers in cfs. Flow is

based on the number of cooling tower pumps on at the time in question. Each ofthe

48 cooling tower pumps is rated at 7500 gpm (16.7 cfs).

82

---

TT

Cooling tower discharge temperature in degrees F. Temperature is continuously

monitored by three thermocouples in the cooling tower discharge flume. Input for

the model

is the average ofthe three readings.

3.0 Thermal Balance Procedure for Determination

ofFully-Mixed Receiving Water Temperature

Fully mixed receiving water temperatures are determined using a thermal balance model that

considers condenser cooling water flow, effective condenser cooling water discharge

temperature, upstream river flow, and upstream river temperature. The basic thermal balance

equation for determination

ofthe fully-mixed receiving water temperature is:

T

FM

= TEFQcw

+

T

lJ

sCO.5*QAY)

Qcw

+

(0.5*QAv)

Term

T

FM

Qcw

Tus

Description

Calculated fully-mixed receiving water temperature in degrees F.

Calculated effective condenser cooling water discharge temperature after mixing

with cooling tower discharge, in degrees F. Determined using thermal balance

procedure outlined in step 2.0.

Condenser cooling water flow in cubic feet per second. Flow

is based on the

number

of circulating water pumps on at the time in question. Each ofthe four

circulating water pumps is rated at 230,000 gpm (512.5 cfs).

Available receiving stream dilution flow in cfs. Available dilution flow

is

determined by subtracting condenser cooling water flow from the upstream river

flow.

Ifthe upstream river flow is equal to or less than the condenser cooling water

flow, the available receiving stream dilution flow is zero. Upstream river flow

is the

average value of flow recorded during the 24-hour period preceding the time in

question. The primary source

of flow data is the gauging station operated by the

Army Corps

of Engineers at the Brandon Road Lock and Dam. Secondary sources

for flow data are the gaging station on the Chicago Sanitary and Ship Canal at

Romeoville operated by the United States Geological Survey, and the Des Plaines

River gaging station at Riverside, operated by the Army Corps

of Engineers.

Upstream river temperature

in degrees F. Temperature is continuously monitored

by Bailey and Endeco systems in the station intake canal.

4.0 Near-Field Thermal Compliance Matrix

The excel-based Near-Field Thermal Compliance Matrix can be used by station personnel on an

as-needed basis to insure that compliance with the Secondary Contact thermal standards

is

maintained under current receiving stream conditions. Input the condenser cooling water

discharge temperature and flow and the cooling tower discharge temperature and flow; the

matrix displays fully-mixed receiving water temperatures at various upstream river flows and

temperatures. A sample output

of the matrix is attached.

83

---

Example of Joliet 29 Near-Field Compliance Matrix:

APPENDIX 4

River Temperature

Upstream River

Available Dilution

Flow cfs

Flow' cfs

75

76

77

78

79

80

81

82

83

84

85

86

87

88

2050

513

92.30

92.37

92.45

92.53

92.60

92.68

92.76

92.84

92.91

92.99

93.07

93.14

93.22

93.30

2250

713

91.79

91.90

92.00

92.10

92.21

92.31

92.42

92.52

92.62

92.73

92.83

92.94

93.04

93.14

2450

913

91.32

91.45

91.58

91.71

91.83

91.96

92.09

92.22

92.35

92.48

92.61

92.74

92.87

93.00

2650

1113

90.87

91.02

91.17

91.33

91.48

91.63

91.79

91.94

92.09

92.25

92.40

92.55

92.71

92.86

2850

1313

90.44

90.62

90.79

90.97

91.15

91.32

91.50

91.67

91.85

92.03

92.20

92.38

92.55

92.73

3050

1513

90.04

90.24

90.43

90.63

90.83

91.03

91.22

91.42

91.62

91.82

92.01

92.21

92.41

92.61

3250

1713

89.66

89.87

90.09

90.31

90.53

90.75

90.96

91.18

91.40

91.62

91.84

92.05

92.27

92.49

3450

1913

89.29

89.53

89.77

90.01

90.24

90.48

90.72

90.95

91.19

91.43

91.67

91.90

92.14

92.38

3650

2113

88.95

89.20

89.46

89.71

89.97

90.23

90.48

90.74

90.99

91.25

91.50

91.76

92.02

92.27

3850

2313

88.62

88.89

89.16

89.44

89.71

89.98

90.26

90.53

90.80

91.08

91.35

91.62

91.90

92.17

4050

2513

88.30

88.59

88.88

89.17

89.46

89.75

90.04

90.33

90.62

90.91

91.20

91.49

91.78

92.07

4250

2713

88.00

88.31

88.62

88.92

89.23

89.53

89.84

90.15

90.45

90.76

91.06

91.37

91.68

91.98

4450

2913

87.72

88.04

88.36

88.68

89.00

89.32

89.64

89.97

90.29

90.61

90.93

91.25

91.57

91.89

4650

3113

87.44

87.78

88.11

88.45

88.79

89.12

89.46

89.79

90.13

90.47

90.80

91.14

91.47

91.81

4850

3313

87.18

87.53

87.88

88.23

88.58

88.93

89.28

89.63

89.98

90.33

90.68

91.03

91.38

91.73

5050

3513

86.93

87.29

87.65

88.02

88.38

88.74

89.11

89.47

89.83

90.20

90.56

90.93

91.29

91.65

5250

3713

86.68

87.06

87.44

87.81

88.19

88.57

88.94

89.32

89.70

90.07

90.45

90.83

91.20

91.58

5450

3913

86.45

86.84

87.23

87.62

88.01

88.40

88.79

89.17

89.56

89.95

90.34

90.73

91.12

91.51

5650

4113

86.23

86.63

87.03

87.43

87.83

88.23

88.63

89.03

89.44

89.84

90.24

90.64

91.04

91.44

5850

4313

86.01

86.43

86.84

87.25

87.66

88.08

88.49

88.90

89.31

89.72

90.14

90.55

90.96

91.37

6050

4513

85.81

86.23

86.65

87.08

87.50

87.92

88.35

88.77

89.19

89.62

90.04

90.46

90.89

91.31

84

---

CITATIONS AND REFERENCES:

Advanced Notice of Proposed Rulemaking (ANPR) on Part 131 water quality regulations. 63

Fed. Reg. 36750. July 7, 1998.

AquaNova International and Hey and Assoc. Lower Des Plaines River Use Attainability

Analysis. Draft report, March, 2003. Prepared for Illinois Environmental Protection

Agency.

Brady, Randall A., 1993. Upper Illinois Waterway Study. Interim Report. Aerial Survey

of

Surface Temperatures Using Infrared Scanning Techniques. Summer, 1993. Randa,ll A.

Brady,

Ag Consultant and Remote Sensing, 621 No. Parkway, Santa Cruz, CA

_________.1994. Upper Illinois Waterway Study. Interim Report. Aerial Survey

of Surface Temperatures Using Infrared Scanning Techniques. Winter, 1994. Randall A.

Brady,

Ag Consultant and Remote Sensing, 621 No. Parkway, Santa Cruz, CA

Burton, G.

A.,

Jr. 1995a. The Upper Illinois Waterway Study Interim Report: 1994-1995

Sediment Contamination Assessment. Institute for Environmental Quality, Wright State

University. Prepared for Commonwealth Edison Co., Chicago, IL.

______. 1995b. Reviews ofLiterature Concerning: 1) Effects ofTemperature on

Freshwater Fisk, 2) Effects on Freshwater Biota and Interactions

of Temperature and

Chemicals, and 3) Effects

ofTurbidity and Barge-Traffic on Aquatic Ecosystems.

Institute for Environmental Quality, Wright State University. Prepared for

Commonwealth Edison Co., Chicago, IL.

Burton,

G. A. Jr., L. Burnett, P. Landrum, M. Henry, S. Klaine and M. Swift. 1992. A Multi-

Assay Multi-Test Site Evaluation

of Sediment Toxicity. Final Report to Great Lakes

National Program Office, U.S. EPA, Chicago, IL.

Burton

G. A, Jr., K. Kroeger, J. Brooker and D. Lavoie. 1998. The Upper Illinois Waterway

Ecological Survey (July 1997-March 1998). Continuous In Situ Toxicity Monitoring and

Thermal Effect Characterization Tasks. Final Report. Institute for Environmental

Quality, Wright State University. Prepared for Commonwealth Edison Company,

Chicago, IL.

Burton G. A, Jr. and C. Rowland. 1999. The Upper Illinois Waterway Ecological Survey (July

1998-0ctober

1998). Continuous In Situ Toxicity Monitoring and Thermal Effect

Characterization Tasks. Final Report. Institute for Environmental Quality, Wright State

University. Prepared for Commonwealth Edison Company, Chicago, IL.

Cairns J.

J. Jr, Buikema A. L. Jr., Heath AG, Parker Be. 1978. Effects oftemperature on aquatic

organism sensitivity to selected chemicals. Virginia Water Resources Research Center.

Bulletin 106. Blacksburg,

VA

85

---

CITATIONS AND REFERENCES (continued):

Cairns J. J. Jr., Heath

A.

G., Parker B.C. 1973. The effects oftemperature upon the toxicity of

chemicals to aquatic organisms. Report to Congress by the Environmental Protection

Agency. Part 3. Serial No. 93-14. Washington DC.

Clean Water Act,

§ 303(c)(2)(A)

Code of Federal Regulations, 40 CFR § 131.10, §131.12, §131.3

EA Engineering, Science and Technology. July, 1992. Compilation/Annotation of Physical,

Chemical

&

Biological Data Pertaining to CSSC, Lower Des Plaines

&

UIW, 1980-

1991. Main Report

&

Appendices.

1993, Mesohabitat Survey

ofthe Upper Illinois

Waterway

RM 270 to 324.3, Report by EA to Commonwealth Edison Company,

Chicago, IL.

_______________. 1994, The Upper Illinois Waterway Study: Interim

Report: 1993 fisheries investigation RM 270.2-323.2. Report to EA by Commonwealth

Edison Company, Chicago, IL

_______________. 1995a, The Upper Illinois Waterway Study: Interim

Report: 1994 fisheries investigation RM 270.2-323.2. Report by EA to Commonwealth

Edison Company, Chicago, IL

_--------------,--. 1995b, The Upper Illinois Waterway Study: Draft:

Summary Report: Ichthyoplankton. Report by EA to Commonwealth Edison Company,

Chicago,IL

_______________. Dec. 18. 1995c. Reviews ofLiterature Concerning:

Effects

of Temp. on fish, Effects ofFreshwater Biota from Interactions of Temperature

and Chemicals, and Effects

ofTurbidity and Barge Traffic on Aquatic Ecosystems.

_____________' 1997. 1998. 1999.2000.2001. 2002). Temperature

and Dissolved Oxygen Monitoring ofthe Des Plaines River at the I-55 Bridge, Report by

EA to Midwest Generation EME, LLC, Chicago,

IL.

_______________. 2001,2002 Upper Illinois Waterway fisheries

investigation

RM

272.4-286.4, Report by EA to Midwest Generation EME, LLC,

Chicago, IL.

.

__________--:-:-__:--_. February, 2003. Thermal Plume Surveys on the Des

Plaines River Near Joliet Stations 9 and 29, June-September, 2003. Report by EA to

Midwest Generation, EME, LLC, Chicago, IL.

86

---

CITATIONS AND REFERENCES (continued):

EA Engineering, Science and Technology. (May, 2003--unpublished) Habitat Survey ofthe

Dresden Pool.

Electric Power Research Institute (EPRI). 198 I. Literature review: Response

of fish

to thermal discharges. EPRI, Palo Alto, CA.

ENSR Consulting and Engineering, 1995. Upper Illinois Waterway Study Summary Report.

Physical-Chemical Study

of the Upper Illinois Waterway. Summer 1993-Spring 1994.

Document

Number 95-03-BI98, August 1994.

Environmental Science and Engineering, Inc. 1994. The Upper Illinois Waterway Study; Interim

Report: 1993 benthic macroinvertebrate investigation and habitat assessment,

RM 272.0-

323.0. Report by

ESE to Commonwealth Edison Company, Chicago, IL.

_______________. 1995. The Upper Illinois Waterway Study;

Interim Report: 1994 benthic macroinvertebrate investigation and habitat assessment,

RM 272.0-323.0. Report by ESE to Commonwealth Edison Company, Chicago, IL.

EPA.

August,2003. Strategy for Water Quality Standards and Criteria. Office of Science and

Technology, EPA-823-R-03-010, Washington, D.C.

EPA. Summer, 2002--Biological Assessments and Criteria: Crucial Components

of Water

Quality Programs. Office

of Water, EPA 822-F-02-006, Washington, D.C.

EPA.

May 1991. Policy on the Use of Biological Assessments and Criteria in the Water

Quality Program (including transmittal letter from Tudor T Davies dated June 19, 1991).

U.S. EPA, Washington, D.C.

EPA. 1986. Quality Criteria for Water (EPA 440/5-86-001)

EPA. 1977. Interagency 316(a) technical guidance manual and guide for thermal

effects sections

of nuclear facilities environmental impact statements. U.S. EPA,

Washington, D.C.

EPA. 2002. Draft Guidance: National Management Measure Guidance to Control Nonpoint

Source Pollution from Urban Areas. U.S. EPA, Washington, D.C.

Federal Water Pollution Control Agency (FWPCA), 1968. Report

ofthe Committee on Water

Quality Criteria ("Green Book").

Final Report: Aquatic Ecological Study

ofthe Upper Illinois Waterway, Vol. 1&2,

Commonwealth Edison Company, with the assistance

ofthe Upper Illinois Waterway

Ecological Study

Task Force, March 26, 1996

87

---

CITATIONS AND REFERENCES (continued):

Great Lakes Environmental Center, July, 2002. Proceedings Summary Report, National

Symposium, Designating Attainable Uses for the Nation's Waters. Prepared for U.

S.

EPA, Office of Science and Technology, Water Quality Standards Branch.

Gutreuter, S.,

J. M. Dettmers, and D. H. Wahl. 2003. Estimating mortality rates of adult fishes

from entrainment through the propellers

ofriver towboats. Transactions ofthe American

Fisheries Society 132:646-661.

Holly,

F. M. Jr., A.A. Bradley, M. Wilson, J.B. Parrish III, 2002 (in preparation). Thermal

Environmental Forecasts for Upper Illinois Waterway. Prepared for Midwest Generation.

Chicago, IL.

Holly, F.M., Jr. 1994. Thermo-hydrodynamic model

of Chicago Sanitary and Ship Canal and

Lower Des Plaines River. Iowa Institute

of Hydraulic Research Limited Distribution

Report No. 227, The University

ofIowa

Holly, F.M., Jr., A.A. Bradley, W. Walker, S. Wright, 1995. Estimation of Water Temperature

Exceedance Probabilities in the Upper Illinois Waterway Using Thermo-Hydrodynamic

Modeling. Iowa Institute of Hydraulic Research Limited Distribution Report, The

University

ofIowa.

Holly, F.M., Jr., D. Mossman, D. Bonnett and R. Einhellig, 1992. Computational Thermal

Regime and Derating Analysis for Joliet Power Station. Iowa Institute

of Hydraulic

Research Limited Distribution Report, The University

of Iowa.

Holly, F.M., Jr., Yang, J.c., Schwarz, P., Schaefer, J., Hsu, S.H., and Einhellig, R., 1990.

CHARIMA--Numerical simulation

of unsteady water and sediment movement in

multiply connected networks

of mobile-bed channels. Iowa Institute of Hydraulic

Research Report No. 343, The University

ofIowa.

Illinois Administrative Code, Title 35, Chapter I, Subtitle C § 302.402

Illinois Environmental Protection Act, Section 27(a)

Illinois Environmental Protection Agency, Year 2000 305(b) report,

p. 14-17

Illinois Environmental Protection Agency Recommendation in AS96-10, filed

August

9, 1996

Illinois Department

of Natural Resources, 2002 Illinois Fishing Digest. p.40-43.

Illinois Department

of Public Health, Year 2002 Fish Advisory Listing. March 14,2002.

88

---

CITATIONS AND REFERENCES (continued):

Illinois Pollution Control Board Order and Opinion, AS96-1 0, dated October 3, 1996

Illinois Pollution Control Board Order and Opinion, AS96-1 0, dated March

16, 2000

Institute for Environmental Quality. 1995. Review

ofthe Literature Concerning: Effects of

Temperature on Freshwater Fish, Effects on Freshwater Biota from Interactions of

Temperature and Chemicals, and Effects of Turbidity and Barge-Traffic on Aquatic

Ecosystems. Wright State University Final Report to Commonwealth Edison, Chicago,

IL.

Lawler, Matusky

&

Skelly Engineers. 1995. Chemical Risk Screening, The Upper Illinois

Waterway Study Final Report. Prepared for CornEd, Chicago, IL

Lower Des Plaines River Use Attainability Finalized Minutes from April

3, 2002 Meeting

(e:mail to workgroup members from Neal O'Reilly, Hey and Associates. dated June 25,

2002 )

Lowery, D. R., Pasch,

R. W., and Scott, E. M. (1987). "Hydroacoustic survey of

fish populations ofthe lower Cumberland River," U.S. Army Engineer

District, Nashville, Nashville,

TN.

Metropolitan Water Reclamation District of Greater Chicago (MWRDGC), 1992. Water Quality

Modeling for the Chicago Waterway and Upper Illinois River Systems, Prepared by

Camp, Dresser

&

McKee, Inc.

O'Flaherty, L.M. Summary Report on Periphyton/Phytoplankton

in the Upper Illinois

Waterway. Department

ofBiology, College ofArts and Science, Western Illinois

University, Macomb,

IL

Ohio Administrative Code, Chapter 3745-1-07 Water use designations and statewide criteria.

Effective date: February 22, 2002 (revised: July 7, 2003).

Ohio Environmental Protection Agency (Ohio EPA). 1978. Guidelines for the

submittal

of demonstrations pursuantto Sections 316(a) and 316(b) ofthe Clean Water

Act and Chapter 3745-1

ofthe Ohio Administrative Code. Ohio EPA, Division of

Industrial Wastewater, Columbus, OH.

________. 1987. Biological criteria for the protection of aquatic life:

Volumes I-III. Ohio Environmental Protection Agency, Columbus, OH.

________. 1989a. Biological criteria for the protection of aquatic life: Vol. III.

Standardized field and laboratory methods for assessing fish and macroinvertebrate

communities. Div. Water Quality Monitoring and Assess., Surface Water Sect.,

Columbus, OH

89

---

CITATIONS

AND REFERENCES

(continued):

Rankin, E.T. 1989. The qualitative habitat evaluation index (QHEI): rationale, methods and

applications. Ohio EPA. Div. Water Quality Planning and Assess

.. Ecological Assess.

Sect., Columbus, OH.

Reash, R.,

G. Seegert, and W. Goodfellow. 2000. Experimentally-derived upper

thermal tolerances for redhorse suckers: revised 316(a) variance conditions at

two generating facilities in Ohio. Environmental Sci.

&

Policy VoI3:S191-196.

Todd, B. L. and

e. F. Rabeni. 1989. Movement and habitat use by stream-dwelling smallmouth

bass. Transactions

ofthe American Fisheries Society 118:229-242.

Water Quality Standards Handbook: Second Edition, U.S. EPA Office

of Water, August 1994,

Section 2.4,

p. 2-5.

Wisconsin Department

ofNatural Resources. Guidelines for Designating Fish and Aquatic Life

Uses for Wisconsin Surface Waters. November 2002 Draft.

Yoder,

e.O., R. J. Miltner and D. White, 2000. Using Biological Criteria to Assess and Classify

Urban Streams and Develop Improved Landscape Indicators. In proceedings

ofthe

National Conference on Tools for Urban Water Resource Management and Protection.

published by U.S. EPA, Office of Research and Development, Washington, D.e.

EPAl6251R-00/001,

July 2000.

Yoder, e.O. and E.T. Rankin. 1996. Assessing the condition and status of aquatic life designated

uses in urban and suburban watersheds, pp. 201-226. in L.A. Roesner (ed.). Effects

of

Watershed Development and Management on Aquatic Ecosystems, American Society of

Civil Engineers, New York, NY

90

---

Midwest Generation Comments on Draft UAA Report

INTRODUCTION-- COMMENTS:

Page

Incorrect/lncomplete/Misleading Information

Reference

in Draft UAA Re ort

I-8, bottom

303(d) listing incomplete/abbreviated

Plant design data (in Table 1.2 on page 1-11)

is INAPPROPRIATELY APPLIED to

determine that MWGEN plants consistently

use entire river for cooling--This is

NOT

TRUE

Table is incomplete and values in last column

oftable are either taken out of context or not

properly cited. Insufficient information is

given in order to look up referenced data.

Response/Rebuttal/Revisions Indicated

Should also specifically include: PCBs,

and flow alternation.

It

should also be

noted that heat is NOT listed as a

parameter of concern for any ofthe UAA

segments in the most recent 305(b)/303(d)

reports

Design data should only be considered as

''worst-case''and should not be applied to

any analysis without consultation with

MWGEN on actual station operating

conditions, which are adjusted to ensure

compliance with all thermal limits,

including mixing zone and zone

of passage

provisions required

by Section 302.102 .

In addition, consultant assumes "low flow"

conditions to come to flawed conclusions,

when actual flow data

is readily available

and would show that condenser flow rates

are normally less than the flow in the river

system. Consultant fails to compare actual

temperature data to actual flow data for the

same time periods.

It

is uncertain what the values in the last

column represent, since there were several

different scenarios run

in the thermal

modeling work done as part

of the UIW

Study. Poor citations and lacking

references make fact checking extremely

difficult for this report.

Towers are used to control both near and

far-field thermal compliance. This

information was provided

in MWGEN

presentation to Biological subcommittee.

(Ref: June 4, 2002 presentation)

1-22

footnote

1-23,

#3

Consultant refers to cooling towers being

"commonly used" and "mandatory" with

references that are not cited

Report refers to "improved sediment quality",

but values presented still indicate that

contamination is still prevalent in the

waterway. Need to differentiate results

between main channel and depositional areas.

as well as core versus grab sample results.

Recent DOE EIA 767 data for rivers in IL

and WI show that only 3 out

of 13 and 5

out

of 17 power plants (respectively) have

closed cycle cooling, with the rest being

o en-c

cleo

Biological subcommittee was never been

given the opportunity to review the

USEPA sediment sampling

methods/results; Sediment contamination

is very heterogeneous in nature; a few

samples and averaged results shouldn'tbe

relied upon to establish that overall quality

has im roved.

10/22/03--Revision

---

Midwest Generation Comments on Draft UAA Report

WATERBODY ASSESSMENT: Chemical Parameters

CHAPTER COMMENTS:

2-72, top

2nd to last para: ..."no single cause

ofthe low

DO can

be pinpointed." Compare this

statement to the one at the

right»»»»>

ResponselRebuttallRevisions Indicated

Data

is NOT from the same location in the

waterwa

Data provided by MWGEN should not be

taken out

of context; we would have

provided the electronic files, with

accurately documented data,

if a request

had been made to us.

Data on intake and discharge temperatures

at Joliet Stations, provided by MWGEN

during June 4, 2002 subcommittee

meeting, showed maximum month

condenser outlet temperatures, which were

explained to the group as NOT being

representative

ofthe discharge to the river

due to the impact

of cooling tower

operations. Towers are capable

of cooling

the station discharge down by a minimum

of 5 OF before it enters the lower Des

Plaines River and receives further mixing

with ambient river water.

In addition, the condenser outlet

temperatures presented represent the

highest

15 minute value recorded in any

given month, and CANNOT be assumed to

have been

in

effect for the ENTIRE

MONTH, as the consultant did. The

Consultant then proceeds to apply his

inaccurate assumption on main river

temperature to the remainder

ofthe UAA

Report, to the extent that he alleges that

MWGEN was in violation

ofthe

Secondary Contact thermal limits for

months at a time.

No actual data or information is presented

to support this position. Temp/DO studies

done for MWGEN do not show any strong

correlations.

p. 2-79, 2nd para: states the causes

of

instantaneous DO excursions in the

Dresden Pool as being definitively caused

by nutrient enrichment and cloudy days.

(No citation

of supporting data)

Example

of inconsistencies in report

statements/conclusions.

I0/22/03--Revision

2

---

Midwest Generation Comments on Draft UAA Report

WATERBODY ASSESSMENT: Chemical Parameters

CHAPTER COMMENTS:

Page

Reference

2-74

2-81, third

bullet

IncorrectJIncomplete/Misleading Information

in Draft UAA Re ort

Reference to QUAL2E model as applicable to

UAA

Response/Rebuttal/Revisions Indicated

QUAL2E assumes steady state flows,

complete vertical/horizontal mixing, one-

way flow---all

ofwhich are not applicable

to the lower Des Plaines River.

Complete misrepresentation and misuse of

MWGEN data, resulting in false

assumptions and conclusions which target

thermal discharges as being

in

noncompliance with existing standards.

MWGEN has actual data, as well as recent

river study results, to demonstrate that this

is NOT TRUE.

10/22/03--Revision

3

---

Midwest Generation Comments on Draft UAA Report

WATER BODY ASSESSMENT FOR TEMPERATURE--

CHAPTER COMMENTS:

(pages 2-82 through 2-1 04--original draft references)

Page

Reference

IncorrectlIncompletelMisleading Information

in Draft UAA Re ort

Response/RebuttaIlRevisions Indicated

2-82,

para. 2

Reference to Table 1.2 (p. 1-11 )-- power plant

capacities and heat rejection information

This information represents design or

worst-case

values, and are NOT

re resentative of current lant 0 erations.

Reference to Table

1.2 (p 1-11 )--summer

delta T

in the river at low flow

Reference to Joliet Cooling Towers (in

footnote to Table 1.2,

p. 1-11)

Report cites history

of thermal limits in the

waterway, with particular emphasis on the

role that CornEd has played--but fails to

mention that all prior proceedin s were

supported by biological data;

2-82,

para. 2

2-82,

para. 2

2-82,

para. 3

2-85, mid

MWGen uses the 24 cooling towers at

Joliet 29 to the full extent possible to

control our thermal discharges to comply

with both near and far-field thermal limits.

When towers alone cannot reduce

temperatures to

an acceptable level,

significant unit deratings (i.e. decreases in

megawatt load) are taken to control

temperatures in the waterway. MWGen

has consistently had to derate during

critical summer periods, when the demand

for electricity

is highest. MWGen has

incurred costs in

$M's to remain in

compliance with the existing thermal

limitations.

I-----:-:---I-,-,---...,-----,-:----::--,----:-:-::---:----:----:---t_

This information was NOT presented in

either the Holly (1994) or Wozniak (2002)

references--Where did it come from and

what

is the intent of presenting it? Holly

and Bradley (1994) report reference

is also

absent from review

of literature listin .

1--::-....,....,.---1'-::--=------::-:-:---:::----::---:::-----:-:----+

10/22/03--Revision

4

---

Midwest Generation Comments on Draft UAA Report

WATER

BODY ASSESSMENT FOR TEMPERATURE--

CHAPTER COMMENTS:

(Pages 2-82 through 2-1 04-original draft references)

MWGen operates Joliet Station in order to

consistently comply with both near and far-

field thermal limitations, utilizing cooling

towers and significant unit deratings, when

necessary to ensure compliance. Since

1999, cooling towers have been in use and

condenser flow rates have been adjusted

downward to optimize station operations,

as well as cooling tower efficiency.

Supporting data confirming continuing

compliance during the 1999 summer

period, as well

as more recent periods, has

been presented to both IEPA and USEPA

(June,

2002).

Page

IncorrectJIncomplete/Misleading Information

Response/Rebuttal/Revisions Indicated

Reference

in Draft UAA Re ort

1-'2=-=-:":86=':;::':"'::-1-'

,...,-;---~=

para. I

Recent thermal plume studies performed

by MWGen (EA.

2003), along with

temperature analyses previously presented

to IEPA and USEPA (June,

2002) clearly

demonstrate Joliet Stations' continuing

compliance with all applicable thermal

standards and there

is no interaction of

thermal plumes from Joliet 9 and 29 until

temperatures are already within the

specified Secondary Contact limits.

In addition, the data provided by MWGEN

DOES NOT show main river temperature,

so there is no actual data to support the

consultant's simplistic and inaccurate

assumptions.

10/22/03--Revision

5

---

Midwest Generation Comments on Draft UAA Report

WATER

BODY ASSESSMENT FOR TEMPERATURE--

CHAPTER COMMENTS:

(Pages 2-82 through 2-1 04--original draft references)

Page

Reference

2-86

para. 3

The erroneous assumptions made regarding

the required power plant flow versus the

river flow are not supported

by any actual

data and allege that Midwest Generation

has been in chronic violation

ofthe

Secondary Contact thermal limits. The

assumption that there

is no mixing zone in

the river is based on the gross

misinterpretation

of station operating

parameters, river flow dynamics and

appalling disregard for the need

of

substantive support for such statements.

Data from recent thermal plume studies

conducted by Midwest Generation clearly

refute these allegations.

Condenser discharge temperature (as

reported

in

Joliet Station #29 DMRs and in

the presentations given by Wozniak in

2001 and 2002) is NOT equivalent to the

temperature entering the lower Des Plaines

River. Use ofthe cooling towers, which

actually treat almost 50%

ofthe condenser

flow (due to lower than design condenser

flow rates), decrease discharge canal

temperatures by a minimum

of

5 of. This "effective discharge" then

enters the river and mixes with cooler

upstream water to effect addition

reductions in overall plume temperature.

The maximum General Use limit

is 33.9 of

(93 °F)--which is identical to the I-55

adjusted therrnallimit during the summer

months. I-55 temperatures have remained

at or below

93 of since continuous

monitoring began in 1988.

10/22/03--Revision

6

---

Midwest Generation Comments on Draft UAA Report

WATER

BODY ASSESSMENT FOR TEMPERATURE

--

CHAPTER COMMENTS:

(Pages 2-82 through 2-1 04--original draft references)

Page

Reference

2-88,

para. I

ResponselRebuttallRevisions Indicated

Mass-balance calculations, as well as

actual field data, demonstrate that this is

NOT TRUE. The Joliet Stations are

operated to ensure continuing compliance

with all existing near and far-field thermal

limitations. MWGen has presented a

proposed near-field thermal compliance

model to IEPA and USEPA for use in

monitoring and assessing near-field

compliance on an on-going basis. This

model is based

on IEPA'sguidance on

Point Source Wasteload Allocation (1991).

Ifthe condenser discharge temperature

were equivalent to the fully mixed

temperature in the river, the I-55 thermal

limits would consistently be exceeded

during the hot summer months, which

continuous monitoring data has shown is

not the case. Compliance with the I-55

adjusted thermal standards has been

maintained since the limits became

effective in Nov. 1996.

10/22/03--Revision

7

---

Midwest Generation Comments on Draft UAA Report

WATER BODY ASSESSMENT FOR TEMPERATURE

--

CHAPTER COMMENTS:

(Pages 2-82 through 2-1 04--original draft references)

Page

Reference

2-89

Incorrect/lncomplete/Misleading Information

in Draft UAA Re ort

Consultant wrongly assumes constant low

flow conditions dominate river system,

without checking real data

to confirm validity

of assumptions, and then misuses MWGEN

provided information to determine how our

plants impact the waterway. This is

extremely biased, as well as unrealistic. In

fact, elsewhere in the report, the flow ofthe

waterway is characterized as greatly

fluctuating, as the graph on this page shows.

It

should be noted that this graph is

"replotted" from the US Army Corps

of

Engineers website, which depicts 6 am values

only, so this graph is NOT representative of

continuous flow data for the entire time period

and only represents one hour each day. In

addition, it was acknowledged that the flow is

supplemented by diversion flow during the

summer period---Both these factors would

indicate that there is no "constant" low flow

which would result in the kinds

of situations

that the consultant presumes to occur in the

lower Des Plaines river.

Response/RebuttallRevisions Indicated

MWGEN maintains continuous records of

intake, discharge and I-55 temperatures, as

well as circulating water flow rates,

cooling tower flow rates and cooling

efficiency and river flow rates. MWGen

also retains a complete record

of2-hour

Corps of Engineers flow data for Brandon

Road. All ofthis REAL DATA was

offered to the IEPA consultants, but it was

never requested.

Another example

of inconsistency within

the report and/or disregard for information

or data that weakens consultant's

arguments.

Information presented to the workgroup

discussed the use ofthe towers and their

efficiency in reducing the temperature of

the station discharge a minimum of5 OF

before it enters the river. (p. 60 of 6/4/2002

presentation). This data was not included

in the draft UAA Report.

There are many open cycle power plants in

the Midwest, including several on the Ohio

River in Ohio and Wabash River in

Indiana. Closed cycle cooling was a

requirement for all plants built after 1970,

which

is the type of plant the consultant

may be referring to. The Joliet and Will

County plants were built before this

requirement was

in place, and were built to

utilize cooling water from an

industrialized, Secondary Contact

waterway, not comparable to any river in

Portage or Kenosha, Wisconsin.

ef. DOE EIA Data from 2000)

10/22/03--Revision

8

---

Midwest Generation Comments on Draft UAA Report

WATER BODY ASSESSMENT FOR TEMPERATURE--

CHAPTER COMMENTS:

(Pages 2-82 through 2-1 04--original draft references)

Page

Reference

2-89,

bottom

#4-#

11 discuss impacts of "excessive"

temperature but does not quantify the

magnitude at which adverse effects would be

expected to occur.

10/22/03--Revision

Data recently presented to IEPA and

USEPA confirm that even under critical

summer conditions, Joliet Station

continues to remain

in compliance with all

near and far-field thermal limits, through

the adjustments in station circulating flow

rate, use of cooling towers and unit

deratings.

These points appear to be taken from a

basic textbook on water pollution.

How

do these points relate to specific

information provided for lower Des Plaines

River? How does the real in-stream data

compare? Are these effects documented

in

the Lower Des Plaines River?

9

---

Midwest Generation Comments on Draft UAA Report

WATER

BODY ASSESSMENT FOR TEMPERATURE--

CHAPTER COMMENTS:

(Pages 2-82 through 2-1 04--original draft references)

Page

Reference

2-91 top

2-91,

bottom

IncorrectJIncomplete/Misleading Information

in Draft UAA Re ort

#11 implies that there is a proliferation

of

blue-green algae in the waterway

The statement made in the last sentence

of

paragraph 1: "... the standards should not be

developed to protect the

inferior

biotic

composition. The standards should also

contain some margin

of safety." (emphasis

added) implies that the Secondary Contact

thermal limits are not adequately protective

of

the types of aquatic species expected to be

found in this waterway.

What criteria does the consultant use to

determine that the current biotic composition

is "inferior" for the lower Des Plaines River,

or is this

just another opinion, without

evidence or support?

Define "inferior" in the context ofthe UAA

reach. Years

of monitoring data show

significant improvements in the fish

community over time, despite continued input

of heat.

Response/Rebuttal/Revisions Indicated

Data provided

by the UIW study on

periphyton and phytoplankton was not

referenced, although the information was

readily available to the consultant.

Contrary to the consultant's statements, the

UIW studies

of phytoplankton and

periphyton clearly show that the system

is

NOT dominated by blue-green algae.

It

is,

in fact, populated by the same species

assemblage as other similar river-reservoir

navigation channels. Phytoplankton

density at Joliet was comparable to the

density observed in Pool 19

ofthe

Mississippi River, which is not thermally

impacted.

The premise that water temperatures in the

main body

ofthe river are equivalent to

Joliet Station discharge temperatures is

prevalent throughout the report and is

ENTIRELY INCORRECT (as explained

previously).

Midwest Generation'srecently submitted

report (dated January 24, 2003, as well as

the more recently issued revision)

discusses this matter in great detail and

relies on a comprehensive data base

of

field-collected data to come to the

conclusion that the existing limits do

adequately support the current and

potential aquatic populations in the

waterway, based on other permanent

limiting factors in the waterway.

The so-called "inferior" species are those

that are best suited to the available

habitat/flow regime present in the

waterway.

10/22/03--Revision

10

---

Midwest Generation Comments on Draft UAA Report

2-91

bottom

2.92 mid

The last statement on the page implies that the

current Secondary Contact thermal limits are

already above the lethal limit for indigenous

fish species, and charges IEPA with

supporting a "lethal standard".

To the contrary, the in-stream biological data

demonstrates that there has been no lethality

observed with the current Secondary Contact

thermal standards in place.

Is there truly a beliefthat the river

"can reach

its ecological optimum that would

be

commensurate with the goals ofthe Clean

Water Act.",

that is supported by actual data,

or is this solely the opinion

ofthe consultant?

The only way a statement like this could be

made is by believing the simplistic and

erroneous assumption that water

temperatures in the main body

ofthe river

are allowed to remain at 100 of (the

Secondary Contact maximum limit) for

an

unspecified amount oftime, thereby

eliminating any species whose lethal

thermal limit is below this value.

If one

reads all

ofthe requirements related to the

Secondary Contact thermal limits, it can be

seen that any water temperatures in the

main body

ofthe river are strictly limited

between

93 of and 100 of to only 5% of

the hours in any 12-monthperiod. In

addition, the general water quality

provisions at I1.Adm. Code 302.102

specifically state the mixing zone and zone

of passage requirements be maintained for

all thermal discharges to the waterway, be

it General Use or Secondary Contact. The

purpose

ofthese combined regulations is to

ensure that there continues to be an

adequate margin

of safety to ensure the

health and well-being

ofthe indigenous

aquatic community.

Our understanding of the UAA process

was that is it was the consultant'stask was

to take all available data on the waterway

and provide a summary which could then

be used the IEPA to determine which water

quality limitations would be adequately

protective

ofthe existing and potential

indigenous aquatic community. The

statements made within the

draft: report go

well beyond this, with little,

if any,

supporting information and data.

At no point during the UAA workgroup

discussions was there any preconceived

idea that the entire lower Des Plaines River

would become full General Use, other that

that professed by the consultant, at the

outset

ofthe study. This bias has carried

through since the first workgroup meeting,

and is apparent the

draft: report.

10/22/03--Revision

11

---

Midwest Generation Comments on Draft UAA Report

WATER

BODY ASSESSMENT FOR TEMPERATURE --

CHAPTER COMMENTS:

(Pages 2-82 through 2-1 04--original draft references)

Page

Reference

2-92

2-93

bottom

IncorrectlIncomplete/Misleading Information

in Draft UAA Re ort

Consultant surmises,

by selectively pulling

information from previous Board rulings, that

the Secondary Contact standards were

implemented and accepted

..."to avoid the cost

of cooling on the Lower Des Plaines River

that was perceived

as hopelessly polluted."

Response/Rebuttal/Revisions Indicated

This statement seriously misrepresents the

basis upon which the determination

of the

appropriateness

ofthe Secondary contact

standards, as well as previous thermal

variances, was based. Significant amounts

of actual field data, biological, chemical

and physical, were presented to determine

the ecological and biological integrity

of

the waterway (not dissimilar to what the

current UAA study should be doing).

Based on the data presented, the

determination was made, by both Agency

and supporting consultants, that the lower

Des Plaines River could not support a full

complement

of aquatic life due to

ermanent limitations unrelated to heat.

.

If

temperatures at or above 100 OF were

prevalent in the river, there would be

massive fish kills observed, or the marked

absence

offish during the hottest times of

the year. MWGEN's continuing fisheries

monitoring program has not documented

either ofthese occurrences. To the

contrary, the program continues to

document a varied assemblage

ofwarm

water species thriving within

close

proximity to our thermal discharges.

IDNR also has supporting data on fisheries

in

the waterway and can confirm that no

fish kills have been documented

in

the

lower Des Plaines River even in 1999 .

10/22/03--Revision

12

---

Midwest Generation Comments on Draft UAA Report

WATER

BODY ASSESSMENT FOR TEMPERATURE --

CHAPTER COMMENTS:

(Pages 2-82 through 2-1 04--original draft references)

Page

Reference

2-93

IncorrectlIncomplete/Misleading Information

Response/Rebuttal/Revisions Indicated

in Draft

UAA Re ort

All

ofthe species listed in Figure 2.44 can

and do live

in the lower Des Plaines River.

The most recent EA fisheries study (2001),

which was submitted to the UAA

workgroup as well as IEPA'sconsultants,

shows that the species assemblage in the

upper and lower Dresden pools are

dominated by gizzard shad, bluntnose

minnow, bluegill, emerald shiner, green

sunfish, common carp, spot tail shiner and

bull head minnow. In addition, the

populations offreshwater drum,

smallmouth bass, largemouth bass and

channel catfish have all either increased or

stayed relatively constant between the

years 1994-1995 and 2000-2001. All

of

the fisheries monitoring work is done

during the period from May through

September, during the height

ofthe warm-

weather period

ofthe year. Ifthe

consultant is correct and the entire Dresden

pool'stemperature has exceeded the lethal

limit for these species, then one would not

expect to find them thriving in the system.

2-93/2-94

Estimated maximum temperature

in

the

Upper Dresden Pool

is not equal to the pre-

cooling tower, condenser outlet temps.

provided by MWGENI

Alleging noncompliance with the existing

thermal limits, without proofor

justification,

is not within the scope ofthe

UAA work.

Typographical,

as well as significant

grammatical errors are found throughout

the report. Missing pages/sections, etc.

Spell-check was hot done prior to submittal

of re ort to IEPA.

The discharge temperatures are measured

at the condenser outlet and do not reflect

the impact of the cooling towers on

decreasing this temperature before

it is

discharged to the main body

ofthe river.

Under even the most critical weather and

flow conditions, the use

ofJoliet's coolin

lO/22/03--Revision

13

---

Midwest Generation Comments on Draft UAA Report

towers, along with significant unit

deratings, ensures that compliance with all

applicable thermal limits continues to be

maintained.

2-94

bottom

10/22103--Revision

Careful review ofthe existing data would

show that the values that the consultant

purports are representing the temperatures

in the main body ofthe river are actually

maximum recorded condenser outlet

temperatures, and do not account for the

. cooling provided by the towers that were in

operation at the time, nor is the actual river

flow during this time considered.

The consultant also assumes that the design

data provided

by the UIW report and

Midwest Generation are representative

of

the actual operating conditions at the plant.

Our facilities could not physically operate

at maximum loading

if river flow

conditions were consistently below our

circulating water flow rates. Back pressure

would necessitate significant unit

deratings. However, this seldom occurs

for two reasons: (1) river flow

is

constantly fluctuating by orders of

magnitude, and therefore, extremely low

river flows are only sporadic (i.e. on the

order of hours), rather than chronic, and (2)

Midwest Generation maintains vigilant

watch over river and station operating

temperatures and use the available cooling

towers, as well as unit deratings, to ensure

that all thermal limits are met in the main

body

ofthe river (i.e. where the Secondary

Contact limits are

in effect).

Trying to equate a condenser outlet

temperature with a main river temperature,

using a worst case estimate

of condenser

and river flow

is NOT appropriate,

especially when actual data for all time

periods in question

is available.

Thermal plume monitoring studies done

during 2002 by Midwest Generation

conclusively show that the thermal plumes

from the two Joliet stations well within the

current Secondary Contact limits and their

discharge temperatures are not equivalent

to the temperature

in the main body ofthe

river under typically encountered summer

weather flow and

0 eratin conditions.

14

---

Midwest Generation Comments on Draft UAA Report

WATER

BODY ASSESSMENT FOR TEMPERATURE

--

CHAPTER COMMENTS:

(Pages 2-82 through 2-1 04--original draft references)

Page

Reference

2-95 mid

In reality, the maximum General Use

therrnallimit

is 93 "F-which is identical to

the maximum adjusted I-55 standard that is

applicable to Midwest Generation's

discharges.

Errors

ofthis nature should not occur in a

carefully prepared technical report. The

reader should not be forced to make these

significant editorial corrections.

The discharge canal temperatures plotted

in Figure 2.46 represent condenser outlet

temperatures, and do not reflect the

beneficial impact

ofthe cooling towers at

Joliet 29, which significantly decrease the

overall temperature

ofthe discharge before

it enters the lower Des Plaines River.

10/22/03--Revision

15

---

Midwest Generation Comments on Draft UAA Report

WATER BODY ASSESSMENT FOR TEMPERATURE--

CHAPTER COMMENTS:

(Pages 2-82 through 2-1 04--original draft references)

Page

Reference

2-96

fto

rs during

OF, even

this

erthe

Ie to an

is noway

termined

resents

on

15

urn

d

for

The first sentence in para. 2 states that "

...the

Secondary Contact Indigenous Aquatic Life

standard is above the lethal temperature

of

several warmwater fish species." The

consultant goes on to say that adult fish would

vacate the river during the hotter months

of

the year to escape the "lethal" temperatures

allowed in the waterway.

ResponselRebuttallRevisions Indicated

There is no current regulatory requirement

to maintain any specific condenser

discharge temperature, as long

as the main

body

ofthe river is within the specified

Secondary Contact thermal limits at the

edge

ofthe allowable mixing zone and the

zone

of passage considerations are met.

Midwest Generation continues to operate

the two Joliet Stations to consistently

comply with these limitations.

Ifthis were truly the case, Midwest

Generation'sroutine fisheries monitoring

program, as well as the programs run

by

the Illinois Department ofNatural

Resources, would pick up such a drastic

change. In reality, there has been, and

continues to be a healthy assemblage

of

resident warmwater fish species in the

waterway, despite the continued operations

ofthe Joliet units. Avoidance ofthe

immediate discharge canal has been

documented during the hottest times

ofthe

year, but fish continue to be found both

upstream and downstream

ofthese areas.

There

is no data to suggest a "mass

migration"

of fish to the Kankakee River

during the summer period. Nor is there

any evidence to support the consultant's

supposition that younger fish are killed by

higher temperatures. To the contrary, the

Midwest Generation fisheries monitoring

program continues to collect both adult and

young fish throughout the expanse

ofthe

Dresden Pool.

10/22/03--Revision

16

---

Midwest Generation Comments on Draft UAA Report

WATER BODY ASSESSMENT FOR TEMPERATURE--

CHAPTER COMMENTS:

(pages 2-82 through 2-1 04--original draft references)

Page

IncorrectJIncompletelMisleading Information

Response/Rebuttal/Revisions Indicated

Reference

in Draft UAA Report

2-96

The lower Des Plaines River

is not currently

The exact definition

of Secondary Contact

bottom

classified

as "marginal" or "nuisance", as

is as follows: (II.Adm. Code Title 35,

incorrectly stated by the consultant in the

Subtitle C, Chapter

I, Section 302.402)

seventh line

ofthe third paragraph.

Secondary contact and

indigenous aquatic life standards

are

intendedfor those waters not

suitedfor general use activities

but which will be appropriate

for

all secondary contact uses and

which will be capable of

supporting an indigenous

aquatic life limited only by the

physical configuration

ofthe

body

ofwater, characteristics

and origin ofthe water and the

presence

ofcontaminants in

amounts that do not exceed the

water quality standards listed in

SubpartD.

Based on this definition, the current

Secondary contact standards continue to be

appropriate for the lower Des Plaines

River.

There

is no inference in the

language above that such waters are

considered "nuisance" or "marginal", only

that they are influenced by factors which

may prevent them from becoming full-

body contact recreational or supporting a

balanced indigenous aquatic community.

10/22/03--Revision

17

---

Midwest Generation Comments on Draft UAA Report

WATER BODY ASSESSMENT FOR TEMPERATURE--

CHAPTER COMMENTS:

(pages 2-82 through 2-1 04--original draft references)

Page

Reference

2-97

IncorrectJIncompletelMisleading Information

in Draft UAA Re ort

The consultant again attacks the

Secondary

Contact thermal limit as being "lethal".

Although the consultant states that they were

directed

by IEPA to defer on a

recommendation regarding future temperature

limitations for the lower Des Plaines River,

they have done exactly that. In line 10, they

state that a socio-economic study

is " ... the

only reason a departure from the Illinois

General Use standard can be justified. This

study has concluded that the first five reasons

for downgrading the thermal standard form

that specified

by the Illinois General Use

standards cannot

be applied."

Response/Rebuttal/Revisions Indicated

As stated earlier, the assumption made

by

the consultant that the limit allows 100 OF

temperatures in the main body ofthe river

is WRONG. The additional safeguards

provided by excursion hour allowance

between

93 OF and 100 of, along with the

mixing zone and zone

of passage

provisions, adequately ensures that aquatic

organisms in the system are adequately

protected. The field monitoring data

collected by both Midwest Generation and

MWRDGC demonstrate this, in that there

have been consistent populations

of

indigenous aquatic organisms throughout

the lower Des Plaines River, even with the

addition

ofheat.

How can the consultant base this

conclusion on "reasonable scientific

confidence" when the data needed to draw

this conclusion

is not available, by the

consultant's own admission? Also, since

the General Use thermal limits

do not

currently apply to the upper Dresden Pool,

there is no reason why the 5 OP delta T

limit should be expected to be met.

The correct legal interpretation

is that if

anyone or more ofthe 6 UAA regulatory

factors is met, a less than fully

fishable/swimmable use can be justified.

We submit that the actual field data show

that UAA Factors 3, 4 and/or 5 are met

in

the Lower Des Plaines River. Therefore, a

socio-economic impact study (Factor #6)

is

NOT the sole reason for a departure from

the Illinois General Use standards.

1O/22/03--Revision

18

---

Midwest Generation Comments on Draft UAA Report

2-98

The two issues which IEPA requested the

consultant address related to temperature

were:

(I) determination ofwhether current thermal

conditions are detrimentally impacting the

aquatic community that inhabits the study

reach, and

(2) determination

ofwhether

the

currently

applicable state standard (Secondary Contact

and Indigenous Aquatic Life standards

modified

(what does this mean?)

for the

Dresden Pool)

fs.-are

adequate to protect the

aquatic community otherwise capable

of

inhabiting the study reach.

bottom

of page: example of poor grammar

"issues addressed to be addressed..."

Consultant's conclusions are not based on the

actual data presented for consideration by

MWGEN and others.

The Midwest Generation report (January,

2003 and October, 2003 revision)

specifically addresses these two issues and

should be carefully reviewed by both the

Agency and the Biological Subcommittee.

Our preference was to use actual field-

collected data, as opposed to unsupported

allegations and statistics, to develop

biologically supportable thermal limits for

the lower Des Plaines River. Our

intention

is to work with the Agency and

other stakeholders to propose a new

thermal standard that would be both

biologically protective and financially and

technically attainable.

MWGen submits, based on the available

data, that Factors 3, 4 and/or 5 are met for

both the Brandon and Dresden Pools.

(1)

Ammonia toxicity is known to be

influenced

by temperature, but the source

of ammonia itself has not been fully dealt

with. Ammonia is sometimes considered a

natural pollutant, in which case it would

fall under UAA factor #1.

(2) The system is not dominated by blue-

green algae (as documented by the UIW

report, Chapter 5). The system also does

not support swimming, therefore, this point

is not applicable to the lower Des Plaines

River

in any way.

(3) Here, the consultant alleges that

temperature is the sole reason why some

values below the General Use dissolved

oxygen limit have been encountered at

certain locations, although other causes

of