ATTACHMENT 1

Map of Upper Illinois Waterway Showing Location of MWGen Plants

Electronic Filing - Received, Clerk's Office, August 4, 2008

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ATTACHMENT 2

1996 AS 96-10 BOARD OPINION

Electronic Filing - Received, Clerk's Office, August 4, 2008

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ILLINOIS POLLUTION CONTROL BOARD

October 3, 1996

IN THE MATTER OF:

)

)

PETITION OF COMMONWEALTH

)

EDISON COMPANY FOR

ADmSTED

)

STANDARD FROM 35 ILL. ADM. CODE )

302.211 (d) and

(e)

)

AS 96-10

(Adjusted Standard-Water)

OPINION AND ORDER OF THE BOARD (by E. Dunham):

This matter comes before the Board on an adjusted standard petition filed by

Co=onwealth Edison Company (CornEd) on May 16, 1996. CornEd filed an amended

petition on June 20, 1996 which was supplemented and corrected on July 11, 1996. The

Illinois Environmental Protection Agency (Agency) filed its

reco=endation instanter on

August 9, 1996. CornEd has published a request for waiver

of hearing on the petition and no

request for hearing

was received from the public. Therefore, hearing is waived.

Based upon the record and review

of the factors involved in consideration for alternate

thermal standards and adjusted standards, the Board finds that CornEd has demonstrated that the

adjusted standard

is warranted. Therefore, the Board will grant the adjusted standard for

temperature

as proposed by CornEd.

ALTERNATE THERMAL

STANDARD/ADmSTED

STANDARD PROCEDURE

CornEd requests that the Board grant alternate thermal standards for CornEd's Joliet,

Will County, Crawford and Fisk generating stations in place

of the requirements of 35 TIL

Adm. Code 302.211(d) and (e). The authority for granting alternate thermal standards is

provided by 35 TIl. Adm. Code 304.141(c) and the Clean Water Act (CWA) at 316(a) (33

U.S.C. 1326(a)). The Board's rules at 35

m.

Adm. Code 304. 141(c) provides as follows:

The standards

of this chapter shall apply to thermal discharges unless, after

public notice and opportunity for hearing, in accordance with Section 316

of the

CWA and applicable federal regulations, the Administrator and the Board have

determined that different standards shall apply

to a particular thermal discharge.

(35

TIl. Adm. Code 304. 141(c).)

Section 316(a)

of the Clean Water Act provides:

With respect

to any point source otherwise subject to the provisions of Section

306

of this Act, whenever the owner or operator of any such source, after

opportunity for public hearing, can demonstrate

to the satisfaction of the

Administrator (or,

if appropriate, the State) that any effluent limitation proposed

for the control

of the thermal component of any discharge from any such source

Electronic Filing - Received, Clerk's Office, August 4, 2008

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2

will require effluent limitations more stringent than necessary to assure the

protection and propagation

of a balanced, indigenous population of shellfish, fish

and wildlife in and on the body

of water into which the discharge is to be made,

the Administrator (or,

if appropriate, the State), may iropose an effluent

limitation under such section on such plant, with respect to the thermal

component

of such discharge (taking into account the interaction of such thermal

component with other pollutants), that will assure the protection and propagation

of a balanced indigenous population of shellfish, fish and wildlife in and on that

body

of water.

USEP

A's regulations establish the showing necessary to demonstrate alternate thermal

limitations:

Existing dischargers may base their demonstration upon the absence

of prior

appreciable harm

.... Any such demonstration shall show: (I) That no

appreciable harm has resulted from the normal component

of the discharge

(taking into account the interaction

of such thermal component with other

pollutants and the additional effect

of other thermal sources) to a balanced,

indigenous community

of shellfish and wildlife in and on the body of water into

which the discharge has been made

....

(40 C.F.R. 125.73(c).)

The Board's procedural rules do not specify the procedural requirements for an alternate

thermal standard determination.

In

its June 20, 1996 order the Board determined to follow the

procedures

of Section 106. Subpart G for an adjusted standard.

The Board's responsibility in this matter arises from the Environmental Protection Act

(Act) (415 ILCS

5/1

et seq. (1994)). The Board is charged therein to "deterntine, defme and

iroplement the environmental control standards applicable in the State

of illinois" (415 ILCS

515(b)(1994))

and to "grant ..... an adjusted standard for persons who justify such an

adjustment" (415 ILCS

5/28.I(a)(1994)).

More generally the Board's responsibility is based on

a system

of checks and balances integral to illinois environmental governance: the Board is

charged with the rulemaking and principal adjudicatory functions, and the Agency is

responsible for carrying out the principal administrative duties.

The adjusted standard provision

of the Act, at Section 28.1 (415 ILCS 5128.1 (1994)),

was created by the legislature to provide an expedited alternative to site-specific rulemaking.

The result

of either an adjusted standard or a site-specific rule proceeding is the same (Le.,

relief from a particular rule).

In

both a general rulemaking proceeding and a site-specific

rulemaking proceeding, the Board, pursuant

to Section 27 of the Act, is required to take the

following factors into consideration: the existing physical conditions, the character

of the area

involved, including the character

of surrounding land uses, zoning classifications, the nature of

the existing

air

quality, or receiving body of water, as the case may be, and the technical

feasibility and economic reasonableness

of measuring or reducing the particular type of

pollution. (See specifically, Section 27(a).)

Electronic Filing - Received, Clerk's Office, August 4, 2008

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3

Section 28.1 of the Act establishes the level of justification required for an adjusted

standard and also requires the adjusted standard

to be consistent with Section 27(a). The level

of justification required, as set forth in Section 28.1(c), is that the petitioner present adequate

proof that:

1)

Factors relating to that petitioner are substantially and significantly different

from the factors relied upon by the Board in adopting the general regulation

applicable to that petitioner;

2)

The existence of those factors justifies an adjusted standard;

3)

The requested standard will not result in environmental or health effects

substantially or significantly more adverse than the effects considered by the

Board in adopting the rule

of general applicability; and

4)

The adjusted standard is consistent with any applicable federal law.

BACKGROUND

CornEd

is a public utility serving approximately eight million customers in the northern

fifth of Illinois. (pet. at 1.) Four

of CornEd's generating stations (Joliet, Will County,

Crawford and Fisk) discharge heat to the Des Plaines River or other waterways that ultimately

combine with the Des Plaines River.

(Am. Pet. at 4.) The discharges from these stations are

subject

to Secondary Contact and Indigenous Aquatic Life Water Quality Standards (35 Ill.

Adm. Code 303.441.)

Joliet Station

Joliet Station

is a steam-electric generating facility capable of producing 1,414 gross

megawatts

of electricity. (Am. Pet. at 9.) The station is located in Will County, approximately

one mile southwest of the City

of Joliet, Illinois, adjacent to the Des Plaines River. (Am. Pet.

at 9.) Joliet Station consists

of three coal-fired units, all of which utilize open cycle, once-

through condenser cooling systems.

The station has two thermal discharges

to the Des Plaines River; one from Station #9 on

the east bank

of the river and the other from Station #29 on the west bank. The maximum

design temperature rise in the circulating cooling water

is approximately 9.4°F, with a total

circulating water flow rate of 2, 620 cubic feet per second.

(Am. Pet. at 9.) Both thermal

discharges flow into the Des Plaines River approximately one-half mile downstream of the

Brandon Road Lock and Dam, at river mile 285, which

is about seven miles upstream of the 1-

55 Bridge. (Am. Pet. at 9.)

Electronic Filing - Received, Clerk's Office, August 4, 2008

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4

Will County, Fisk, and Crawford Statious

Will County, Crawford, and

Fisk Stations (collectively, the "Canal Stations") are steam

electric geuerating facilities capable

of producing 1154, 581, and 342 gross megawatts of

electricity, respectively. (Am. Pet. at 10.) Will County Station is located in Romeoville,

illinois, near the intersection

of the Chicago Sanitary and Ship Canal and Romeo Road. (Am.

Pet. at 10.) Crawford Station is located in Chicago, near the intersection

of the Stevenson

Expressway and Pulaski Avenue. (Am. Pet. at 10.) Fisk Station is located near downtown

Chicago,

at the intersection of Loomis Street and the Chicago Sanitary and Ship Canal. (Am.

Pet. at 10.) The generating units

of each Canal Station are coal-fired, and each utilizes opeu

cycle, once-through condenser cooling systems

The Canal Stations discharge into the Chicago Sanitary and Ship Canal: Will County at

river mile 295.5, Crawford

at river mile 318.5, and Fisk at river mile 322. (Am. Pet. at 10.)

The maximum design temperature rise in the circulating cooling water is approximately 11.1of

for Will County, 12.0°F for Crawford, and 12.2°F for Fisk. (Am. Pet. at 10.)

APPLICABLE REGULATIONS

Each

of the discharges from these four generating stations is subject to secondary

contact and indigenous aquatic life water quality standards (35 ill. Adm. Code 303.441).

The temperature standard for secondary contact waters requires that temperature not exceed

34°C (93°F) more than 5% of the time, or 37.8°C (100°F) at any time. (35 Ill. Adm. Code

302.408.)

However, the lower Des Plaines River between the Interstate 55 Bridge and the head

of the Illinois River (confluence of the Des Plaines River with the Kankakee River), a

segment known as the "Five-Mile Stretch", is subject to the more stringent general use

water quality standards. Among other requirements, the general use standards governing

temperature require that maximum temperature rise above natural temperatures not exceed

2.8°C (5°F) and water temperature not exceed 16°C (60°F), during winter months (Dec.

through Mar.)

or 32°C (90°F), during summer months (Apr. through Nov.), more than 1%

of the hours in a 12 month period ending in any month, and never exceed these

temperatures by more than 1.7°C (3°F) (35

TIL

Adm. Code 302.211(d) and (e».

RELATED PROCEEDINGS

In 1987, CornEd requested that the Board determine, pursuant to 35 Ill. Adm. Code

302.211(f), that the thermal discharges from the Joliet Station have not caused and cannot

reasonably

be expected to cause significant ecological damage to the general use waters. The

Board found that CornEd

had made the requisite showing under 302.211(f). (In the Matter of:

Proposed Determination

of No Significant Ecological Damage for the Joliet Generating Station

(November 15, 1989), PCB 87-93.)

Electronic Filing - Received, Clerk's Office, August 4, 2008

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5

In

the course of PCB 87-93, the Sierra Club, participating as an ioterveuor, argued that

CornEd had failed to make a sufficient showiog

of no significant ecological impact because,

among other reasons, the Joliet plant contributed

to violations of Section 302.21l(d) and (e) io

the waters

of the Five-Mile Stretch.

In

response, CornEd argued that these provisions were

ioapplicable, priocipally because Joliet Station discharges ioto secondary contact waters.

CornEd further committed

to implement an operating plan for the Joliet Station which would

ensure that the Joliet Station would limit its megawatt output as necessary to avoid exceedences

of the monthly maximum temperature standard

of Section 302.21l(e).

In

PCB 87-93, the Board addressed these issues as follows:

The Board finds that 302.21l(d) and (e) do apply to the effect

of [CornEd's]

discharges. Although Secondary Contact Standards may govern at the poiot

of a

particular discharge, it

is possible for an entity located upstream of the begioniog

of the General Use waters to cause or contribute to exceedences of the General

Use Water Quality Standards.

In

fact, the reason the Board required [CornEd] to

perform a thermal demonstration under subsection

(t) is because the Board

recognized that a source which discharges

to Secondary Contact waters could

affect downstream General Use waters.

The Board finds, however, thatio this proceediog the issues of whether

violations

of the 302.211 standards have occurred io the Five-Mile Stretch and,

if they have, whether [CornEd]

is responsible for them, is at best ancillary to the

matters at hand. The only proper forum for the Board to hear allegations

of

violation of the Board's rules is an enforcement action brought pursuant to Title

VIII

of the Illioois Environmental Protection Act. The Board cannot and will not

here reach the issue

of whether [CornEd] is io violation of any Board water

quality standard.

Consideration

of whether there is non-compliance of the waters of the Five-Mile

Stretch with the Board's water temperature standards can enter the iounediate

case only where non-compliance stands

as proof of significant ecological damage

associated with [ComEd's] discharge.

The Board finds that there is no substantive iodication that any of the observed

temperatures io the Five-Mile Stretch have caused significant ecological damage.

(pCB 87-93 at 19; 105 PCB Gp. at 167.)

Regardiog whether CornEd's operatiog plan

was acceptable to satisfy the requirements

of Section 302.21l(e), the Board found:

The Board believes that [ComEd] has a viable monitoriog program

... which,

although not field tested at the time

of hearing, is capable of assuriog

adjustments to operations should they prove necessary to ensure compliance.

(PCB 87-93 at 21.)

Electronic Filing - Received, Clerk's Office, August 4, 2008

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6

In

PCB 87-93, the Board found that CornEd successfully demonstrated that the heat

discharges from the Joliet Station have not caused and cannot be reasonably expected to cause

significant ecological damage to the waters

of the Five-Mile Stretch.

In

so doing, the Board

also found that the temperature

of the waters of the Five-Mile Stretch was not a factor limiting

its quality, and that other factors continue to override the effect

of temperature on the

waterway. These overriding factors include loss

ofhabitat due to channelization, disruption of

habitat due to barge traffic, and the presence of heavy metals and other pollutants in the system.

(pCB 87-93 at 20).

CornEd was granted a variance from the temperature standards

of 35 ill. Adm. Code

302.211(d) for these facilities for a period

of five years. (Co=onwealth Edison v. IPCB

(November 21, 1991), PCB 91-29.) As part

of the variance, CornEd agreed to initiate a study

to establish thermal standards for the facilities.

In

1991, CornEd initiated a study of the entire

stretch

of the Upper illinois Waterway

(UlW)

into which its plants discharge. (Am. Pet. at 4.)

CornEd has submitted the report from this study

as Exhibit 1 of the petition.

ENVIRONMENTAL IMPACT

The upstream reach

of the South Branch of the Chicago River, the Chicago Sanitary and

Ship.Canal,and the

Des Plaines River.is greatly modified by .use.as a.shipping channel with

habitat limited to deep pools without shallows, structure, riffles

of suitable substrates. (Ag. at

6.) The area affected by the proposed adjusted standard

is heavily developed with industries,

including a refinery, a chemical plant and a boatyard. (Ag. at 6.) The waterway

is a very

artificial and significantly modified waterway that

is limited in terms of habitat. (Am. Pet. at

12, Exh.

1- Ch. 2.) Historical practices have caused substantial residual chemical

contamination

to be present

in

the sediments of the waterway. (Am. Pet. at 13, Exh. 1 Ch.4.)

The UIW study concludes that the above ambient water temperatures

in

the UIW during

the winter months are due primarily to discharges from municipal treatment plants, limiting the

organisms that can be maintained in the waterway.

(Am. Pet. at 13, Exh.l Ch. 10 Sec.

10.6.4.) The report also maintains that the organisms limited by the above conditions are

tolerant

of water temperatures warmer than those associated with rivers

in

the region. (Am.

Pet. at 13, Exh. 1 Ch. 8, 9 and 10.)

CornEd contends that its proposed alternate thermal standards are compatible with

protecting species

in

the UIW. (Am. Pet. at 14.) The proposed standards provide for a

gradual, stalr-step increase into the spring and decrease in the fall rather that the 30°F change

that would be permitted by Section 302.211(e), were the requirements

of 302.211(d)

nonexistent.

(Am. Pet. at 15.)

The task force that compiled the UIW study believe it

is appropriate to continue to

monitor and study various ecological aspects of the UlW. (Am. Pet. at 15.) CornEd has

committed

to conduct further investigations on the UlW

in

cooperation with the Sierra Club and

the appropriate governmental agencies.

(Am. Pet. at 16.)

Electronic Filing - Received, Clerk's Office, August 4, 2008

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COMPLIANCE ALTERNATIVES

While CornEd maintains that compliance costs are not a factor

to be considered for

determining applicable thermal standards under the Clean Water Act, it has analyzed costs for

cooling towers

or derating its units to comply with the generally applicable thermal

requirements. (Am. Pet. at 11.) CornEd estimates that the cost

of installing cooling towers at

Joliet would be $68 million.

(Am. Pet. at 11.) CornEd estimates that the cost of derating the

plants

to meet the thermal requirements would be in the range of $3.5 to $16 million annually.

(Am. Pet. at 11.)

The Agency believes that

it

is technically feasible to reduce the temperature of the

effluents by use

of cooling towers and spray ponds. However, the Agency believes that the

cost of providing this cooling may not be economically reasonable when compared to the

likelihood

of no improvement in the aquatic community. (Ag. at 7.)

CONCLUSION

For all

of the above reasons, the Board finds that petitioner has presented adequate proof

ofjustification for the requested adjusted standard as set forth in Section 28.1(c) of the Act and

the requested adjusted standard,

as presented in this proceeding, is consistent with the factors

set forth in Section 27(a)

of the Act. Petitioner has also provided the necessary showing for

alternate thermal standards pursuant

to the Clean Water Act.

This opinion constitutes the Board findings

of fact and conclusions of law in this matter.

ORDER

The following Alternate Thermal Standards shall apply at the I-55 Bridge

as limitations

for discharges from CornEd's plants (Joliet, Will County, Crawford and Fisk) in lieu

of the

requirements

of Section 302.211 (d) and (e):

January

60°F

February

60°F

March

65°F

Apri11-15

73°F

Apri116-30

80°F

May 1-15

85°F

May 16-31

90°F

June

1-15

90°F

June 16-30

91°F

July

91°F

August

91°F

September

90°F

October

85°F

November

75°F

December

65°F

The standards may be exceeded by no more than 3°F during 2

%

of the hours in the 12-

month period ending December 31, except at no time shall CornEd's plants cause the water

temperature at the I-55 Bridge

to exceed 93°F. CornEd's plants continue to be subject to the

Secondary Contact Standards at the point

of discharge.

Electronic Filing - Received, Clerk's Office, August 4, 2008

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IT IS SO ORDERED.

Section

41 of the Environmental Protection Act (415 ILCS 5/41 (1994» provides for the

appeal of

fInal Board orders within 35 days of the date of service of this order. The Rules of

the Supreme Court of Illinois establish filing requirements. (See also

35 Ill. Adm. Code

101.246 "Motions for Reconsideration.

")

I, Dorothy M. Gunn, Clerk of the Illinois Pollution Control Board, hereby certify that

the above opinion and order was adopted on the

day of

, 1996, by a

vote of

_

Dorothy M. Gunn, Clerk

Illinois Pollution Control Board

Electronic Filing - Received, Clerk's Office, August 4, 2008

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ATTACHMENT 3

2000

AS96-10

ILLINOIS POLLUTION CONTROL BOARD OPINION

Electronic Filing - Received, Clerk's Office, August 4, 2008

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ILLINOIS POLLUTION CONTROL BOARD

March 16, 2000

IN THE MATTER OF:

)

)

PETITION OF COMMONWEALTH

)

EDISON COMPANY FOR AN ADJUSTED)

STANDARD FROM

35 ILL. ADM. CODE )

302.21l(d) AND

(e)

)

AS 96-10

(Adjusted Standard - Water)

OPINION AND ORDER OF THE BOARD

(by E.Z. Kezelis):

This matter is before the Board on a February 25, 2000 motion (motion)l by Commonwealth

Edison Company (CornEd) and Midwest Generation, LLC (Midwest), to reopen this docket, AS 96-

10, and substitute Midwest as the petitioner and holder ofthe adjusted standard. Both CornEd and

Midwest have waived hearing in the matter.

On March 9, 2000, the Illinois Environmental Protection Agency (Agency) filed a response to

the motion. In its response, the Agency states that it does not dispute any ofthe factual allegations set

forth in the motion and that it concurs with the request by CornEd and Midwest to reopen the docket

and substitute Midwest as the petitioner and holder ofthe adjusted standard.

BACKGROUND

The Board granted CornEd an adjusted standard from 35 Ill. Adm. Code 302.211(d) and (e) in

an order dated October 3, 1996.

In re

Petition of Commonwealth Edison Company for an Adjusted

Thermal Standard from 35

Ill.

Adm. Code 302.21l(d) and (e) (October 3,1996), AS 96-10. The

October

3, 1996 order granted CornEd an adjusted standard from the thermal standards for discharges

ofcooling water from CornEd'sgenerating stations located in Joliet, Will County, Crawford, and Fisk

(Generating

Stations). In its motion, CornEd states that, in response to the October 3, 1996 adjusted

standard, the Agency issued revised National Pollutant Discharge Elimination System (NPDES) permits

to each ofthese Generating Stations, and that these permits remain in full force and affect. Mot. at 3.

Pursuant to the Electric Service Customer Choice and Rate Relief Law (220 ILCS 5/16-101 et

seq.

(1998)), CornEd agreed, in March 1999, to sell the Generating Stations to Edison Mission Energy,

an indirect, wholly owned subsidiary ofEdison International that specializes in the development,

acquisition, construction, management, and operation ofglobal power production facilities. Mot. at 3-4.

Edison Mission Energy in turn, assigned all of its rights under the purchase agreement with CornEd to

Midwest. Mot. at 4-5. Midwest is a limited liability company that is indirectly owned by Edison

Mission Energy. Mot. at 5. On December 15, 1999, title to the Generating Stations was transferred to

1

Citations to the motion will be referred to as "Mot. at

"

Electronic Filing - Received, Clerk's Office, August 4, 2008

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2

Midwest.

Id.

As a result, Midwest has assumed all rights and obligations associated with the operation

ofthe Generating Stations.

Id.

CornEd and Midwest state in their motion that the operations ofthe Generating Stations will not

change as a result ofthe title transfer. Mot. at 5. The Generating Stations will continue to produce

electricity through the use ofcoal-fired boilers.

Id.

Midwest has retained almost the entire workforce

previously employed by CornEd, including a senior biologist who has been and remains primarily

responsible fur developing and implementing the model used by CornEd to ensure compliance with the

adjusted thermal standards set by the Board in its October 3, 1996 order. Mot. at 6.

DISCUSSION

The Board'sauthority for granting alternate thennal standards is found both in the Clean Water

Act (CWA) (33 U.S.c. 1326(a)) and in 35

Ill.

Adm. Code 304.141(c), that provides:

The standards ofthis chapter shall apply to thennal discharges unless, after public notice

and opportunity for hearing, in accordance with Section 316 ofthe CWA and

applicable federal regulations, the Administrator and the Board has determined that

different standards

shall apply to a particular thermal discharge. 35 Ill. Adm. Code

304.141(c).

Likewise, Section 28.1 ofthe Environmental Protection Act (Act) (415lLCS 5/28.1 (1998))

establishes the level ofjustification required for the Board to grant an adjusted standard. Section

28.1(c) provides:

(c)

Ifa regulation ofgeneral applicability does not specij)! a level ofjustification

required ofa petitioner to qualifY for an adjusted standard, the Board may grant

individual adjusted standards whenever the Board determines, upon adequate

proofby

petitioner, that:

(1)

filctors relating to that petitioner are substantially and significantly

different from the factors relied upon by the Board

in

adopting the

general regulation applicable to that petitioner;

(2)

the existence ofthose factors justifies an adjusted standard;

(3)

the requested standard will not result in environmental or health effects

substantially and significantly more adverse than the effects considered

by the Board in adopting the rule ofgeneral applicability; and

(4)

the adjusted standard is consistent with any applicable federal law. 415

lLCS 5/28.1(c) (1998).

Electronic Filing - Received, Clerk's Office, August 4, 2008

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CornEd sought and, after providing sufficient justification, obtained an adjusted standard from

the temperature standards of35 Ill. Adm. Code 302.21 1(d) and (e), which provide:

Section 302.211

Temperature

***

d.

The maximum temperature rise above natural temperatures shall not exceed

2.8'C (5' F).

e.

In

addition, the water temperature at representative locations in the main river

shall not exceed the maximum limits in the following table during more than one

percent ofthe hours in the 12-month period ending with any month. Moreover,

at no time shall the water temperature at such locations exceed the maximum

limits in the following table by more than 1.7" C (3'F).

°C

of

'C

'F

JAN.

16

60

JUL.

32

90

60

AUG,

32

MAR.

16

60

SEPT.

32

90

APR.

32

90

OCT.

32

90

MAY

32

90

NOV.

32

90

JUNE

32

90

DEC.

16

60

In

the Board'sOctober 3, 1996 order, CornEd was granted the following alternate thermal

standards for discharges from the Generating Stations:

'F

of

JAN.

60

JUNE 16-30

91

FEB.

60

JULY

91

MAR.

65

AUG.

91

APR. 1-15

73

SEPT.

90

APR. 16-30

80

OCT.

85

MAY 1-15

85

NOV.

75

MAY 16-31

90

DEC.

65

JUNE 1-15

90

See

1/1

re

Petition ofCommonwealth Edison Company for an Adjusted Thermal Standard from 35 Ill.

Adm. Code 302.21lCdl and eel (October 3,1996), AS 96-10, slip op. at 7.

Electronic Filing - Received, Clerk's Office, August 4, 2008

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4

In the motion presently before the Board, CornEd and Midwest maintain that the relevant

factors that justified the grant ofalternative thermal standards in

1996,

are not affected by the transfer of

the facility today. Mot. at 7. Specifically, the petitioners assert that the factorsjusti(ying the adjusted

standard involved not the identity ofthe discharger, but rather "the nature ofthe discharge and the

conditions in the receiving waterway, in particular, the lack of impact that the adjusted standards would

have on the ecosystem ofthe receiving waterway ...." Mot. at 7-8. A change in ownership ofthe

Generating Stations should not impact these factors at all. Mot. at 8.

Neither the Act nor the Board'sprocedural rules address the specific type of reliefbeing sought

by these petitioners. However, CornEd and Midwest identified a previous situation in which the Board

granted similar relieE See

In re

Petition ofEnvirite Corporation for an Adjusted Standard from 35 Ill.

Adm. Code 721 Subpart D: List ofHazardous Substances. Appendix 1(November 7, 1996), AS 94-

10. In the Envirite proceeding, Envirite was originally granted an adjusted standard from the listing ofa

particular

waste from the lists in 35 Ill. Adm. Code 72I.Subpart D. At some point after the adjusted

standard was granted to Envirite Corporation, ownership and operation ofthe facility at issue was

transferred to Envirite ofIL, Inc. Both Envirite Corporation and Envirite ofIL, Inc. petitioned the

Board to reopen the adjusted standard docket and substitute the named petitioner. The basic factor in

support ofthe Board'sdecision to grant the Envirite motion was the fact that the relevant mctors

required to justi(y the Board'soriginal decision to grant an adjusted standard had not changed. See

In

re

Petition ofEnvirite Corooration for an Adjusted Standard from 35

Ill.

Adm. Code 721 Subpart D:

List ofHazardous Substances. Appendix I (November 7, 1996), AS 94-10.

CornEd and Midwest urge the Board to apply similar reasoning in this case. As previously

stated, the Agency concurs in this request and, in

fac~

has already transferred NPDES permits for these

Generating Stations to Midwest. Mot. at 5.

CONCLUSION

Based

upon the assurances ofCornEd and Midwest that the management and operation ofthe

Generating Stations will continue unchanged, and upon the Board'sprevious findings ofjustification in its

October 3, 1996 order, tlle Board will officially reopen tllis docket and substitute the name ofMidwest

Generation, LLC, for Commonwealth Edison Company in its October 3, 1996 order.

Electronic Filing - Received, Clerk's Office, August 4, 2008

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5

ORDER

1.

The Board hereby amends its October 3, 1996 order in this matter, and grants to

Midwest Generation, LLC an adjusted standard from 35111. Adm. Code 302.211(d)

and (e) for the Joliet, Will County, Crawford, and Fisk generating stations.

2.

The alternate thermal standards shall apply at the 1-55 Bridge as limitations for

discharges from the above listed generating stations.

3.

In

lieu ofthe requirements of35111. Adm. Code 302.211(d) and (e), the following

standards will

apply:

OF

OF

JAN.

60

JUNE 16-30

91

FEB.

60

JULy

91

MAR.

65

AUG.

91

APR. 1-15

73

SEPT.

90

APR. 16-30

80

OCT.

MAY 1-15

85

NOV.

75

MAY 16-31

90

DEC.

65

JUNE 1-15

90

4.

The standards may be exceeded by no more than 3 degrees Fahrenheit during 2% of

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

Midwest's generating stations cause the water temperature at the I-55 Bridge to exceed

93 degrees Fahrenheit.

5.

Midwest's generating stations continue to be subject to the Secondary Contact

Standards at the point

ofdischarge.

IT IS SO ORDERED.

Section

41 ofthe Environmental Protection Act (415 ILCS 5/41 (1998)) provides for the

appeal offinal Board orders to the Illinois Appellate Court within 35 days ofthe date ofservice ofthis

order. Illinois Supreme Court Rule 335 establishes such filing requirements. See 172111. 2d R. 335;

see also 35111. Adm. Code 101.246, Motions for Reconsideration.

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

6

I, Dorothy M. Gunn, Clerk ofthe illinois Pollution Control Board, hereby certiJY that the above

opinion and order was adopted on the 16th day ofMarch, 2000 by a vote of5-0.

oo~~.

A.,

j{~,.J

ct

.

Dorothy M, Gunn, Clerk

illinois Pollution Control Board

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

ATTACHMENT 4

EXAMPLE

OF BRANDON POOL FLOW FLUCTUATIONS

FOR THE PERIOD 2005 - 2008

Electronic Filing - Received, Clerk's Office, August 4, 2008

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Electronic Filing - Received, Clerk's Office, August 4, 2008

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Electronic Filing - Received, Clerk's Office, August 4, 2008

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Electronic Filing - Received, Clerk's Office, August 4, 2008

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Electronic Filing - Received, Clerk's Office, August 4, 2008

---

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Electronic Filing - Received, Clerk's Office, August 4, 2008

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Electronic Filing - Received, Clerk's Office, August 4, 2008

---

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Electronic Filing - Received, Clerk's Office, August 4, 2008

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ATTACHMENT 5

Chronology

of Midwest Generation (MWGen) Correspondence to Illinois EPA Regarding

the Chicago Area Waterway and Lower Des Plaines Use Attainability Analyses (VAAs)

No.

Correspondence

Description of Correspondence

Chronology

1

March 26, 2002, MWGen

Original MWGen letter to the IEPA in the LDP UAA stakeholder

letter to Toby Frevert,

process identifying several concerns and issues relating to the

IEPA, regarding Lower

contents

ofthe draft documents prepared by IEPA's consultants Dr.

Des Plaines UAA draft

Novotny and Hey

&

Associates, including their failure to consider

documents by IEPA

and/or misrepresentation

of LDP stream

consultants

NovotnynIey

characteristicslhabitatlaquatic/thermal data submitted by MWGen.

&

Associates

2

January 24,2003,

EA

MWGen's original 64-page report presenting proposed thermal

Engineering report

water quality standards for the LDP, submitted to Toby Frevert,

entitled "Appropriate

IEPA, and also to the LDP

UAA Stakeholders Workgroup.

Thermal Water Quality

Standards for the Lower

Des Plaines River"

submitted to IEPA

(revised October 3003

version is

Attachment 6)

3

August 26, 2003,

MWGen'sresponse to USEPA Region 5'sco=ents on MWGen's

MWGen letter to Linda

January 24, 2003 Appropriate Thermal Water Quality Standards

Holst, USEPA Region 5

Report (see Region 5 letter from Linda Holst to Toby Frevert, dated

(Attachment 7)

June 3, 2003). MWGen agrees to malce certain revisions to its

January 2003 thermal standards proposal/report to address USEPA

co=ents and continues to identifY serious inaccuracies,

misrepresentations, and misuse

ofMWGen data in the draft UAA

LDP Report.

4

September 12, 2003,

MWGen identifies numerous errors in the draft LDP UAA report

MWGen letter to Toby

concerning MWGen data and cautions that IEPA's UAA consultants

Frevert, IEPA, regarding

appear to have pre-determined the outcome

ofthe UAA, prior to

revision

of Temperature

consideration of all reasonably available data.

Section

of Draft LDP

UAAReport

5

October 7, 2003, MWGen MWGen co=ents on the most recently revised version ofthe

co=ents to IEPA

thermal chapter

of the Revised Draft LDP UAA Report and the

regarding Revised Draft

supplemental material included in Chapter 8 thereof.

LDP UAA Report

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

6

October 13, 2003,

MWGen provides a revised, proposed thermal water quality

MWGen Revised

standards report for the LDP, submitted to Toby Frevert, IEPA, and

"Appropriate Thermal

also to the LDP UAA Stalceholders Workgroup, which

Water Quality Standards

incorporateslresponds to

co=ents received from IEPA, USEPA

for the Lower Des

Region 5 and MWRDGC personnel.

Plaines" to Toby Frevert,

IEPA

(Attachment 6)

7

October 14, 2003, Dr. G.

Dr. G. Allen Burton of Wright State University reviews and

Allen Burton Review of

co=ents on the misinterpretations of his prior studies on the lower

Draft LDP UAA Report

Des Plaines River by the LDP UAA IEPA consultants. Dr. Burton's

to Toby Frevert, IEPA,

co=ents corroborated many concerns voiced by MWGen

submitted

on behalf of

regarding inaccurate, misleading data and findings in the draft IEPA

MWGen

UAAReport.

8

October 15, 2003,

MWGen provides further co=ent to IEPA on the data

MWGen

co=ents on

interpretation and factual errors and misinterpretations contained in

Draft Thermal Section of

the draft LDP UAA report with respect to thermal issues. Serious

the LDP UAA Report to

problems with the report have still not been corrected.

IEPA

(Attachment 8)

9

October 22, 2003,

MWGen provides further

co=ent to lEPA on the errors and

MWGen revised

misinterpretations contained in the draft LDP UAA report. Serious

co=ents on the Draft

problems with the report have still not been corrected.

Lower Des Plaines UAA

Report

(Attachment 9)

10

November 18,2003, E-

MWGen continues to identify and explain data interpretation and

mail to IEPA LDP

factual errors in the draft LDP UAA Report and to provide

consultant Dr. Vladimir

corrections.

Novotny (with cc to Toby

Frevert)

(Attachment 10)

11

March 24, 2004, MWGen

MWGen provided co=ents on the final UAA LDP Report,

letter to Toby Frevert,

including an attachment containing all prior MWGen LDP UAA

IEPA, with

co=ents on

written co=ents submitted to IEPA. MWGen expresses

Final UAA Report for

disappointment that many of the significant co=ents and

Lower Des Plaines River

corrections made by MWGen and other stakeholders were ignored

(Attachment 11)

in the final UAA LDP Report.

12

July 28, 2004, MWGen

MWGen identifies errors in MWRDGC temperature data used by

co=ents on Lower Des

Mr. Chris Yoder to set the proposed "ambient conditions" relied

Plaines Temperature

upon

in his thermal standards report to IEPA and also provides an

Criteria Derivation Report extensive critique of the methodology utilized and assumptions

prepared by Yoder and

made by Mr. Yoder.

Rankin (June 2004 draft

version) (See

Attachment UU to IEP

A

Statement

of Reasons)

13

March 29,2005, MWGen Extensive co=ents by MWGen regarding draft CAW UAA report.

Co=ents on Draft CAW

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

UAA Report to Scott

Twait, IEPA.

(Attachment 12)

14

June 28, 2005,

MWGen

MWGen comments including data to show that General Use

Supplemental Comments

temperatures are not being met in waterway, contrary to assertions

and Information

in draft CDM report.

Regarding the Draft

CAW

UAA Report which was

prepared by CDM. (See

Attachment 13)

15

June

1, 2006, MWGen

MWGen letter including data to show that MWRDGC'sdischarges

letter and comments on

would not be able to meet proposed non-summer limits and includes

Yoder October

11,2005

a significant critique of MEl's methodology. MWGen expresses

Report to Toby Frevert,

extreme disappointment with the

MEl draft report dated October 11,

IEPA.

(See Attachment

2005, and the fact that MWGen received no response to its prior

UU to

IEPA Statement

comments and that its comments have been largely ignored.

of Reasons)

16

February 27, 2007,

MWGen responds to false allegations

of alleged thermal

MWGen letter to Marcia

noncompliance that arise from the continued errors and inaccuracies

Willhite, IEPA.

in the Final LDP

UAA report. MWGen responds to an allegation by

Prairie Rivers regarding "violations" of existing temperature limits

by MWGen (letter dated December 11,2006). MWGen cbiitiiiues

to point out erroneous conclusions in the Final LDP UAA report.

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

ATTACHMENT 6

January 24, 2003/Revised October 13,2003

EA Engineering Report Prepared for Midwest Generation

"Appropriate Thermal Water Quality Standards

for the Lower Des Plaines River"

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

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 if fishable 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

of the existing

and potential uses

ofthis 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 ofa use which

may include physical, chemical, biological, and economic factors

as described in

Section 131.1 O(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

I.

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.

Ofparticular 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

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

discharge ofsufficient volume ofeffluent discharges without violating State water

conservation requirements to enable uses to be met;

3.

Human-caused conditions or sources

of pollution prevent the attainment of the

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

to leave in place;

4.

Dams, diversions, or other types ofhydrologic 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. chemistIJ}, toxicity testing results,

and ecological assessment) provides

conclusive evidence

ofnonattainment ofwater quality standards regardless ofthe results

ji'OIn other types ofassessment information. Each type ofassessment

is

sensitive to

difftrent types ofwater quality impact. Although rare, apparent coriflicts in the results

from

difftrent 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 methoddoes not require corifirmation with a second method and

that the failure

ofa second method to cOlifirm 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'sWater Quality Standards Handbook,

Second Edition (1994), the use

of biological criteria to support designated aquatic life use

classifications is strongly encouraged.

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

ofbiological

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. FVhen one or more ofthese components

is

2

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

degraded, the health ofthe waterbody will be qlfected, and in most cases, the aquatic life

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, theyprovide information that more rapidly-changing water chemisuy

measurements

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

more reliable assessment

oflong-term biological changes in the condition ofa

waterbody. The cenu'alplllpose

ofassessing biological condition ofaquatic communities

is

to determine how well a water body supports aquatic lift

". (EPA 822-F-02-006,

Summer, 2002)

The importance

ofbasing 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 ofbiological 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

ofexperts in the proceedings ofthe National Symposium on

"Designating Attainable Uses for the Nation's Waters" 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 of the

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 of the 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

of the 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

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

II.

BACKGROUND

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

comprehensive ecosystem study

ofthe entire Upper Illinois Waterway (UIW) perfonned by

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

implementation

ofthis 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 ofNatural Resources

and the Metropolitan Water Reclamation District

of Greater Chicago (MWRDGC), as well as

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

Representatives

ofIllinois 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 frndings need to be carefully considered in the UAA for the Lower Des Plaines

River, including any assessment

of appropriate thennal 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

of UIW Study individual reports and content

summaries

in Appendix 3).

m.

HISTORY OF THE WATERWAY

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 KanIcakee River.

(Figure 1). Early

in the history ofChicago, 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

ofLake 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

of the 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

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

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

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

dams, including a 40-foot dam

just south ofLockport 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

ofthe Kankakee and Des Plaines Rivers.

In its

illW 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 illW.

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

Connty 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 ofJoliet, 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

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

Figure 1:

Figmi:

I,:

Map ofUpper Illinois Waterway, Including UAA Reach

6

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

r'AR-\:i~I::!Tn

1!l!illi:

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Electronic Filing - Received, Clerk's Office, August 4, 2008

---

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

§131.10 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 defmed by Rule 302.102 of lAC, Title 35,

Chapter

1, Subtitle C).

•

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

•

100

OF maximum limitation, year-round

10

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

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

ofheat 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. Ofequal 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

ofpoint 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 ofLake 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

II

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

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

CornEd and overseen

by the mw Task Force. (See IPCB Order and Opinion, AS96-l 0,

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 OF

91°F

91 OF

91 OF

90 OF

85 OF

75 OF

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's plants 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 Quality Standard

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 of that waterbody.

v.

THE RELATIONSHIP BETV,JEEN THE ADJUSTED THERlVIAL STANDARD

AT I-55 AND THE UAA FOR THE LOWER DES PLAmES 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

mw Study, relied upon previously by

12

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

the IPCB in AS96-1 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

ofmeasuring 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 AS96-10. (AS96-10 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 aguatic community of the

UIW". (AS96-

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

After a thorough review

ofthe information presented in the AS96-1 0 proceeding, in October,

1996, the Board granted CornEd the requested I-55 adjusted thermallirnitations 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's support, 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

ofchemical 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. (AS96-10 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

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

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

since the AS96-10 adjusted

thermal standard was granted. No adverse impacts have been

observed on

the indigenous fish community during the course ofthe 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

ofthese 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 !PCB granted the thermal adjusted standard.

VI.

CURRENT THERMAL COMPLIANCE STATUS

All thermal discharges from Midwest Generation's power 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

ofcustomized thermo-hydrodynamic modeling to adjust

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

vn.

PHYSICALIHYDRAULIC/CHEMICAL NATURE OF THE SYSTEM

The upper two-thirds ofthe UIW can best be characterized as a slow-moving, relatively uniform

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-off year-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

ofvertical 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

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

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

ofpool 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.

IS

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

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

reduces the abundance and diversity

ofriverine species. This is a result of interrupting or

eliminating migration, the pooling effect upstream

ofeach 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 illI 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

oftheir

Modified Warmwater Habitat (MWH) designation noted as "impounded". In addition, Ohio also

retains a

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

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

of propeller strikes in

Pool 26 of the 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 ofthe 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

ofEngineers, and are in place exclusively to accommodate flood control and

commercial navigation. There

is no indication that navigationallflow 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 I).

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

significant adverse impacts are associated with the type

of hydraulic modifications found in the

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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's Draft UAA report acknowledged (See Draft

UAA Report, p. 8-16) that

expectations for the Upper Dresden Pool were lower because ofhydraulic 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 Loadiugs 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 discbarge 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 tlle 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 of the states' 2002 section 303(d) Lists,

pathogens are the second most frequent cause ofwater quality inlpairments 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 offine-grained sediments and the presence oflegacy 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 ofaquatic biota present in the

Lower Des Plaines River.

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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. 26-31) Sediment, whether contaminated or not, was found to be the

leading cause

of impairment accounting for 38% of the 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

ofU.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

UlW 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 CornEd 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 offme-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 5-10 years (e.g., DuPage Delta). (Maps

ofQHEI locations are

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

A key limiting factor

to improved biological conditions in the UAA Reach is the phvsical

characteristics

ofthe sediment itself(Le., 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

if the 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 UlW Study, conducted from 1991-1995, a thorough literature review (EA,

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

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

ofcontaminants

ofspecial concern: ammonia, arsenic, cadmium, chlordane, chromium, copper, DDT,

dieldrin, lead,

mercury, nickel, PCBs, PAHs and zinc.

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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 fine-grained, contaminated sediments tend to occur at the tributary mouths and in

backwater and protected areas

of main channel border habitat---especially in the Lockport and

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

of

potential habitat for tlle 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

ofNatural 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 ofPublic 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

tlle 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 perfoffiled 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

of this data should be conducted as part ofthe overall

evaluation

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

viewed

Witll 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 U1W

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 disclosure

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

meaningful, scientific assessment

of the data. The average values do not reveal whether tlley

reflect eitller a broad or narrow range

of individual sediment sampling location results.

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

I

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 detennine if it reflects the results of

main channel or side-channellbackwater 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

ofbarges 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 UlW 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 UlW 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 ofboth biological habitat quality and the

long-tenn 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 pennanently and

are not a limiting factor to the overall improvement ofthe waterway. However, this

contamination

is the result ofhistoric deposition.

It

is not solely due to current point source

discharges which could, theoretically, be controlled through tighter NPDES pennit 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

ofsediment, 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 of the 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..., umelated to water quality," within the

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meaning ofthe UAA regulations (UAA Factor #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

UlW is a difficult task. Elevated water temperatures may increase the rate ofchemical or

biological degradation

of complex organics, strengthen or weaken the physical or electrostatic

bonding

oftoxicants 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 offine-

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 ofPhysical Habitats

An

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

of the original UlW study performed by CornEd, the entire UlW was surveyed to determine the

types, distribution and relative amounts

of physical 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 UlW 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

ofhabitat available in the system is main charmel fMC) and main channel

border fMCB), areas

where the effects of barge transport and industrial and municipal discharges

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

of the

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.

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A greater diversity ofhabitats 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 ofhabitats 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 ofhabitat. 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

of unaltered systems ofcomparable size. For example, Ohio EPA identifies

a target minimum value

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

ofthe 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

IA and lB. The results ofthis 2003 study show that habitat conditions today in the UAA

Reach remain relatively unchanged from when first reviewed as part

ofthe 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

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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

QHEIScore

RM

Right Bank

Left Bank

RM

Right Bank

Left

Banlc

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

lB.

QHEI

Scores at Off-Channel Locations.

Location

Score

405--Treats

53

Island (RM

279.7)

408--Mouth

of

54.7

Jackson Creek

(RM278.3)

414--Bear

40.5

Island Slough

(RM275.9)

418--Mouth

of

57.5

Grant Creek

(RM274.8)

Overall Mean

=

44.3

(Range

=

28-60)

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

Table lC--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 Sinuositv

23

Moderate to Heavy Silt

23

Extensive or Moderate/Extensive

19

Embeddness

Only Substrate Silt or Detritus

10

Poor (s 6) Instream cover

8

Urban or Industrial Riparian Zone

6

Practically speaking, these factors either cannot be remediated (e.g. lack ofsinuosity, 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

ofthis 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 ofmodified warm water habitat streams, and except for depth,

possess

none ofthe characteristics associated with warm water habitat streams.

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Table ID. Comparison of warm water habitat

(WWH)

and modified warm water habitat

(MWH) characteristics of the Des Plaines River.

Brandon Pool

Upper Dresden Pool

WWH Characteristics

No Channelization or

Recovered

Boulder, Cobble, Gravel

Substrates

Silt Free

Good-Excellent

Development

Moderate-Hioh Sinuosilv

Cover Moderate to

Extensive

Fast currents & Eddies

Low/Normal Substrate

Embeddness

Max Depth> 40cm

X

X

LowlNo Riffle embeddness

TotalWWH

1

1

Characteristics

MWH Characteristics

with

Hil:lh Influence

Recent Channelization

Silt/Muck Substrates

X

X

No Sinuosilv

X

X

Sparse/No Cover

X

X

Total MWH tHiahl

3

3

MMH Characteristics With

Moderate Influence

Recoverina Channelization

X

X

High or Moderate Silt Over

Other Substrates

Sand Substance (Boat)

Fair/Poor Development

X

X

Low Sinuosilv

Only 1-2 Cover Types

Intermittent or Interstitial

Max

Depth < 40cm

High Embeddness

of Riffle

v

v

"

A

Substrates

Lack of Fast Current

X

X

Total

MWH

(Moderate

4

4

Total

MWH

(All)

7

7

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With regard to the approach summarized in Table ID, 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 illl 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 conditions/habitat features ofthe waterbody, even

without the presence

ofcontamination, 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 I).

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 of!-

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

of I-55 does not allow attainment of a fish community commensurate with a General

Use designation. The fish community is comparable upstream

ofl-55 where the less restrictive

thermal Secondary Contact standards apply.

Ifthermal levels 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

of varying habitat types as they proceed through the

different life stages.

The overall lack of habitat diversity in the UIW represents a serious

impediment to the development

ofa 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 §I3 I .IO(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

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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 ofnon-

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 ofany refined delineation of use classifications in

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

General Use classification.

In

U.S.EPA'sWater Quality Standards Handbook (Second edition. I 994--p.2.5), the Agency

discusses the need for sub-categories

ofuse 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 helpjitl when a variety ofslllface waters

within distinct characteristics

fit within the same use class, or do llOtjit well illto allY

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's Office 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 refined 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 ofrefining and expanding their

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

streams are classified as Exceptional Use. The majority ofOhio 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 of protection necessary to

protect each

of Ohio'suses.

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In

comparison to minois' existing use designations, the state ofOhio'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'sWarmwater, 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:

I)

"Dams, diversions or other types of hydrologic 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

of pollution 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 of poor 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 aclmowledgement that

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these factors, whether a result of natural conditions, or from the damming ofa 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 ofgreater specificity by states in defining 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's current 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

of protection 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'sWaters" (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

of the UAA Reach!.

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 of the

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.F.R. § 131.10(e).

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An additional use category would allow the State to recogoize 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 ONTBE WATERWAY

A. Effects of Power Plants on Physical Habitat

Power plants add to the availability of physical 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 of the 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 13-15). Being surficial in nature, the thermal

plumes from Midwest Generation'splants 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 (100

%

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 offlow, 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

ofambient solar heating, WWTP discharges, power plant contributions and non-

point source sheet runoff from urbanized areas. (Final Report, UIW Study, 1995. Chapter 3).

The UIW study confirmed the cyclic nature of both 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

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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 UlW 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 Tem perature Distributions

The variability in temperatures inherent in the water source inputs to the UlW, 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 U1W utilize once-through, open cycle cooling

systems. Each plant takes relatively large volumes

ofwater through its condensers and

discharges it directly back into tile 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 UlW Study (ENSR,

1995) , as well as more recent studies (EA, 2003) that demonstrate compliance with the

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

The UlW thermal modeling analysis shows that the overall thermal regime ofthe waterway

downstream ofthe MWRDGC's Stickoey Water Reclamation Plant

(\VRP)

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 Sticlmey 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

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

WRP provides up to 100 %

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

elevates U1W temperatures above what would be found

in

a natural waterway during this time

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ofyear. The result is an altered thermal regime, regardless ofthe input ofheat 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 of this 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'sWill

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

ofl-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 wannest areas in the UAA Reach occur in the near-field plumes immediately downstream of

the points ofdischarge 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

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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 zooplanlcters.

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

downstream. These increases are related to an expansion of available habitats in the lower pools,

the input

of plankton 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 Darn

(RM

271.4) on the lIIinois River was similar to that in

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

of the

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. Phytoplanlcton 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 phytoplanlcton and zooplanlcton 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 ofthe macrophyte beds may fall to low levels during the night, especially in

the two upper pools. This may limit the value ofsuch 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 of benthic invertebrate community

composition within the

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

assemblages

ofnear-fIeld areas at each ofthe generating stations studied generally demonstrated

an overall improvement in community quality relative to areas either upstream or further

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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 ofbottom 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 of thermal 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

of the "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

ofexcess temperature in the Lower Des Plaines River is within

the tolerance range for most

of the 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

therrnallethal 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

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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

ofwarm water limits these exclusion areas to upper water column

layers and that a zone

ofpassage at cooler temperatures (ofat least 75% ofthe cross-section of

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

Study, fly-over, infra-red imagery was taken ofthe waterway. (Brady, 1993-1994) These data

also

confirm the surficial nature ofthe 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 of Brandon Road Lock and Dam, and are

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

ofthe canal in

this area.

The

fishery ofthe mw 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

ofspecies 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

ofnon-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 ofinvasive species in the UAA waterway, using

whatever means are technically and legally available.

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I. Temperature Effects ou 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

ofoxygen 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 Darn 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 TemplD.O. Study Reports).

It

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

andlor increased boat traffic, rather than the input

of heat from power plants. (EA 2001

Temp.ID.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

ofpower plant operations under high

temperature conditions.

Significantly, the water temperature/dissolved

ox)'gen 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

ofdissolved oxygen.

Supplemental physicochemical monitoring done as part

ofMidwest Generation's long-term

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

waterway during the course

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

mininmm 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.

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Short-tenn, 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 UlW 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 ofthis

waterway. Its uniqueness creates additional challenges

in trying to detennine what its overall

potential

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

The unique character

ofthe 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

ofavailability, 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 detennine 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

of the 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 navigationallstorm water control uses

ofthe 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 detennine what the

UAA Reach is capable

of regarding the type of aquatic life it can support with more stringent

water quality limitations

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

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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 UAA Reach, 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

ofHydraulic Research, also continues to perform thermo-

hydrodynamic modeling

of the 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 fnund in reduced numbers.

The important questions here are:

(I)

Is the heat contribution nfMidwest Generation'splants sufficient to raise temperatures to

a range that would exclude expected species, or are the reduced numbers

of such species

a result

ofother factors, such as poor habitat?; and

(2)

What temperature limits are reasonable for the protection

oforganisms 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, spnnsored by ComEdlMidwest

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.

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XI.

ESTABLISHING PROTECTIVE THERMAL LIMITS FOR THE BRANDON

POOL

AND THE UPPER DRESDEN POOL

A.

Temperature is a Uuique 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 (EPR! 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

of the 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

ofhours 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

ofappreciable 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 retum.(EA Fisheries Monitoring Studies, various

years).

The AquaNovalHey 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

"0uvenile 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

ofheat stress by juvenile and adult fish during the summer." (U.S. EPA

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1986). Another interesting aspect oftemperature is that the temperatures fish prefer during the

summer are quite close (often within 2-4

DC)

to those that are lethal (EPRI 1981).

B.

Brandon Pool Current Conditious

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 (Le., the habitat limitations and urbanization) or will not be

changed in the foreseeable future,

if at all (Le., 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 tbat 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 of a 316(a) demonstration under the Clean Water

Ad.

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 ofRepresentative Important

Species (RIS) be assessed.

" A 316(8) demonstration is prepared to support the position that applicable

thermal limits

are more stringent than necessary to

assure the protection and propagation ofnbalanced indigenous community ofshellfish, fish, and wildlife in or on the water to

which the discharge is made. The applicant attempts to demonstrate that alternative, less stringent thenna11imits, will allow the

protection of existing balanced indigenous communities, or alternatively, will allow the development orsnch a community

if

one

is not present currently. This is the showing that CornEd successfully made before the Board in the AS96-1 0 proceeding.

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According to U.S. EPA'sTechnical 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!;

4.

Potentially capable

ofbecoming 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 RlS because this range

ofRlS 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 RlS 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 (RlS) 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 (RlS) for the Lower Des Plaines River is

consistent with accepted methods and guidance. MWGen also considered the inclusion ofa

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 UIW pools. Therefore, these species will be limited naturally by the lack

of suitable habitat.

~

To evaluate this factor, most investigators include at

JellSt

one species at each trophic level (e.g.

II

herbivore. un insectivore, an

omnivore nnd

II

top predator).

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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

ofl-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 (i.e. lack

of habitat). (See Table IF).

These cool water species are habitat limited in the UAA Reach and should not be designated as

RlS. 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 RlS 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 RlS

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.

If

we 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 RlS

for the UAA Reach.

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E.

Temperature Tolerance ofRIS

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 1999-200 I. Thirty-three upstream vs. downstream comparisons can

be made (II taxa x 3

years). In 14

ofthe 33 comparisons, there is no appreciable difference between upstream and

downstream ofI-55

CPE'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'sare higher downstream of I-55. In

sum, eight

ofthe II 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'swere 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

ofmost RIS is not lower upstream ofI-55 and, even when catch rates

are higher downstream

on-55, the difference is slight (bluegill being the only exception), it

appears that changing the thermal standard upstream

ofI-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

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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

ofl-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 fishlkm downstream

ofl-55 compared to about 0.5 fish/!an 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 BIe. Based on low Index

ofBiotic Integrity (IB!) 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 (Le., Upper Dresden Pool). In both 2000 and 2001, mean IBI 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 IBI scores in the low 40s (Ohio EPA 1987).

Thus, even in the "best" areas (Le., those downstream

of I-55), the Des Plaines River fish

community

is poor, with IBI scores not even approaching those that would be expected from a

BIe.

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

ofevidence 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 1-55 where the more restrictive General Use

thermal

WQS apply (Figures 4-6). This indicates that even ifthe observed lBI differences are

due to differences

in thermal standards, the net environmental benefit associated with the more

restrictive General Use standards

is minor.

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Second, the mean IBI score in the Joliet Station discharge was comparable to or higher than the

mean score at the location

just upstream of the station in two ofthe past three years (Figures 4-

6).

Ifthe thennal 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 detennining 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 ofl-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 (Le., 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,

if temperature 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 ofthe 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 ifthis 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 thennal discharge.

In

any case, it is reasonable to conclude that whatever thermal impacts there might be are minor,

limited to a small area,

and of minor consequence compared to other, more limiting factors.

Ifthermal is not the principal factor accounting for the lack ofa 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

ofsiltation in general [e.g., burying of habitats], not the toxic

component

of sediment).

It

is also important to note that of possible 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

ofl-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.

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H.

Would the Upper Dresdeu 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 ofredhorse 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 ofl-55. (Table 3). Some ofthe other reasons why

meaningful improvement in the Upper Dresden Pool aquatic community is unlikely include the

following:

(I) No thermally sensitive cold- or cool-water species are present

(2) Other factors, some

ofwhich 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 ofl-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

ifthere 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 ifGeneral 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 illI scores throughout Dresden Pool suggest that, if anything, it is Lower Dresden pool that

is misclassified. Because of poor 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

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

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

SHORT NOSE

GAR

1

0.01

0.002

UNID GAR

3

0.02

0.007

SKIPJACK HERRJNG

35

0.18

0.087

GIZZARD SHAD

12,070

62.00

29.881

THREADFIN 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

SPOT FIN

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

UNTO 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 BOFFJl..LO

9

0.05

0.022

SPOTTED SUCKER

4

0.02

0.010

SILVER REDHORSE

28

0.14

0.069

RIVER RECHGRSE

6

0.03

0.015

BLACK REDHORSE

1

0.01

0.002

GOLDEN REDHORSE

358

1. 84

0.886

SHORTHEAD RECHGRSE

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

UNIo AMEIORUS

1

0.01

0.002

TADPOLE HADTOM

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

UNIO MORONE

5

0.03

0.012

ROCK BASS

11

0.06

0.027

47

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

TABLE 1E

(cent.)

LOWER DRESDEN POOL

SPECIES

(cent.)

GREEN SUNFISH

PUMPKINSEED

WARMOUTH

ORANGES POTTED

SUNFISH

BLUEGILL

LONGEAR SUNFISH

REDEAR SUNFISH

HYBRID SUNFISH

UNID LEPOMIS

SMALLMOUTH BASS

LARGEMOUTH BASS

UNID MICROPTERUS

WHITE CRAPPIE

BLACK CRAPPIE

BANDED DARTER

YELLOW PERCH

LOGPERCH

BLACKS IDE

DARTER

SLENDERHEAD DARTER

WALLEYE

FRESHWATER DRUM

TOTAL FISH

3,146

26

5

3,040

7,271

67

1

108

110

477

1,659

1

15

35

1

1

126

1

3

1

439

40,394

16.16

0.13

0.03

15.62

37.35

0.34

0.01

0.55

0.57

2.45

8.52

0.01

0.08

0.18

0.01

0.01

0.65

0.01

0.02

0.01

2.26

207.50

7.788

0.064

0.012

7.526

18.000

0.166

0.002

0.267

0.272

1.181

4.107

0.002

0.037

0.087

0.002

0.002

0.312

0.002

0.007

0.002

1. 087

100.000

48

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

TABLE IF.

NUMBER, CPE (No

./km)

I

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

UNIO GAR

SKIPJACK HERRING

GIZZARD SHAD

THREADFIN

SHAD

GOLDEYE

GRASS PICKEREL

NORTHERN PIKE

GRASS CARP

COMMON CARP

CARP

X GOLDFISH HYBRID

GOLDEN SHINER

EMER1\LD SHINER

GHOST SHINER

STRIPED SHINER

SPOTTAIL SHINER

RED SHINER

SPOT FIN

SHINER

SAND SHINER

MIMIC SHINER

SUCKERMOUTH MINNOW

BLUNTNOSE MINNOW

BULLHEAD MINNOW

RIVER CARPSUCRER

QUILLBACK

~IGHFIN

CAR~~UC~R

UNIO 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 HORONE

UNID MORONE

ROCK BASS

GREEN SUNFISH

PUMPKINSEED

O~BGESPOTTED

SUNFISH

BLUEGILL

LONGEAR SUNFISH

HYBRID Sill-IFISH

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

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

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

SPECIES

WHITE CRAPPIE

BLACK CRAPPIE

LOGPERCH

SLENDERHEAD DARTER

WALLEYE

FRESHWATER DRUM

TOTAL FISH

TABLE IF (cant.)

DiS

DRESDEN L&D

__JI

CPE

%_

2

0.05

0.027

8

0.18

0.106

36

0.82

0.477

1

0.02

0.013

1

0.02

0.013

207

4.70

2.745

7,541

171. 39

100.000

50

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

Table 2 U

JOI

er

Therma

ITem oera

t

nres 0

fV

arlOUS

.

D

es

PI'

ames

Ri

vel'HIS

Species

Location

Lifestage

Upper Lethal

Reference

(size)

Temp.

(DC)

C.

carp.

Poland

Juvi

40.6

Horoszewicz 1973

Lake Erie

yay

39.0

Reutter and Herdendorf 1975,

Reutter and Herdendorf 1976

Canada

yay&

35.7

Black, E.C. 1953

Juvi

Channel CF

Lake Erie

165

38.0

Reutter and Herdendorf 1975

Reutter and Herdendorf 1976

AKhatcherv

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 al. 1974

58mm)

SC cooling ponds

40-82

38.5-41.4

Holland, W.E., et al. 1974

mm

WabashR,

IN

49mm

39.0

WAPaRA, Inc. 1976

TN

73, 140

37.4-39.2

Cox, D.K. 1974

Lake Erie

168

38.3

Reutter and Herdendorfl975,

Reutter and Herdendorf 1976

Mississippi River

Juvi

37.3

Banner and Van Arman

1973

VA hatchery

50-100

36.0

Cherry,D:S.;

tlt 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

Mississiooi River

yay

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

yay

28.5

Cvancara, V.A. 1975,

Cyancara, et al. 1977

'" All duta (except redhorse data) from Talmage, S. nnd D. Opresko. 1981. Literature Review: Response ofFish La Thermal Discharges, EPRI

Publication

EA~1840.

Redhorse data from Rell5h, R, G. Seegert. Bnd W. Goodfellow. 2000. Experimentally-derived upper thermal tolerances for

redhorse suckers: revised 316(n) vnrinOl:e conditions!!t two genemting facilities in Ohio. Env. Sci.

&

Policy Vo13:S191-S196.

51

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

T

able 2 U

Jpper

Tberma

ITemoeratures 0 fV'

anous

Des PI'

ames

Ri

ver RIS

Species

Location

Lifestage Upper Lethal

Reference

(size)

Temp. ("C)

LMbass

Paroond, 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, VA 1975

Cvancara, V.A. et al. 1977

Canada Lake

521<

28.9

Black, E.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

aI. 1977

VA

Alabama

Adults

35.0

Wrenn 1980

Green SF

35

Whitford 1970

FWDrum

Mississiooi 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

atC

-

-

_

..

_-_

...

-

.

~. -~

..

_-

.~-

--

Lake Suoerior

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

Mississipoi

YOY

31.0

Cvancara, V.A. 1975

Mississippi

YOY

28.5

Cvancara,

VA 1975,

Cvancara, et al. 1977

BNminnow

WabashR, IN

38

WAPORA, Inc. 1971

New& East

Rivers, VA

50-100

32

Cherrv, et al. 1977

New York 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

(oreferred)

52

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

Table 3.

Comparison of RIS Catch Rates (Nollilll) Upstream and Downstream of 155.

1999

2000

2001

Species

US 155

DSI55

US 155

DSI55

US 155

DSI55

Smallmouth bass

\.2

0.6

0.4

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

\.8

I\.4

9.2

Bluntnose minnow

8.3

12.1

6.2

26.7

20.9

19.1

Smallmouth bulfulo

3.4

3.7

2.4

2.4

2.5

3.2

Channel catfish

3.2

1.9

3.6

2.0

3.5

\.9

Freshwater

drum

3.0

2.6

4.6

\.6

3.0

2.4

Redhorse spp.

0.6

1.1

0.9

0.8

0.2

0.7

53

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

Table 4. KankaI«e, 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.lkm)

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 I km)

Wilmington Dam

YEAR ePE

2000

88.0

I-55

YEAR ePE

2000

104.0

Confluence

YEAR ePE

2000

4.0

Illinois River Downstream of Dresden Lock and Dam (upper Marseilles pool)

YEAR ePE

1999

8.7

1995

15.3

1994

4.3

Illinois 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

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

,

Figure 2. Upper Illinois

,

Waterway Mean

181

Scores, 2001.

-----------i

i

38 to 42 are the NumericallBI Criteria for Ohio EPA's Warmwater Habitat Aquatic Life Use

50 ----------,-----------

48 is the NumericallBI Criteria for Ohio

-~----r--------------------------T-

EPA's Exceptional Warmwater Habitat Aquatic Life Use

-------------------1

48-

I

46

----------------~---------------------------------

-------------------------------------------------------j

,

44

42

1

I

I

I

I-m-------

40

38

~

i

I

I

L

h

E

w 36 -----------------r-------------------------- ------ ,----------------------------------,---------------------

~~

::

--

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

30

~ ~

is

~

the

~ ~

-

NumericallBI

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Criteria

~ ~ ~ ~ ~

for

~ ~ ~

Ohio

~ ~ ~

EPA's

~ ~ ~ ~ ~

Modified

-

~ ~ ~ ~ ~

Warmwater

~

:

~ ~ ~ ~ ~ ~ ~

Habitat

~ ~ ~ ~ ~

(Impounded)

~ ~ ~ ~ ~ ~ ~ ~ ~

Aquatic

~ ~ ~ ~ ~ ~

Life

~ ~ ~

Use

~ ~ ~ ~:~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

« 30 -

'

~

I

W

i

o 28------------------

L

~

--------------1---------------------

:a

a 26

-I- - -- -- -- - --- -- -- -I- - - ---- - - - - - - - - - -- -- - - - - - - - -i-- __ - __ -' _-

-

--

- -

1_ -- - - - - - - - - - - --- - -- --

~

-

24 is the Numericai IBI Criteria for Ohio EPA's

,

Modified Warmwater Habitat (Channel Modified) Aquatic Life Use

286.8 287.9 288.9 289.3 290.3 290.5 290.8

292.5 292_5 293.0 295.4 296.4

River Mile

278.3 279.7 280.5 283.8 284.7 285.1, 285_5

=--

.~-=--=--=--=

---=-=-=-=-- --=--==-= _----=-=-=-- _

.~---=-=

...-

--~

_ -.- _.....

---=-=-=--

--------------------------

--------------------------

--------------------------

16 ------------------r-----------

Downstream

---- ------ -----------

------~----

---

-----.

14 - -

I-55

-- -- - - ---- -- -- -- Upstream I-55 --- - - -- --- - --- -- - -- -- Brandon Pool -- --- - -- - ----- - Lower Locl<port Pool

12-

_

.

274.4 274.8 275.9 276.5

55

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

Figure 3. Upper Illinois Waterway Mean IBI Scores, 2000.

-------------------

-------------------

-- --- - -- -- Brandon Pool --- --- ----

~ ~ ~ ~ ~~ ~ ~ ~ ~ ~ ~ ~ ~ ~~]

.,

----

-

--

--~---

-

--

- -. --

---

._. _ .._._._ Ohio EPA's EJ<ceptional Wannwater Habitat Aquatic Life Use

1

-

m ---I--m-

-I

- - Downstream - - -I' ---------- Upstream I-55

I-55

50 1'.------.-.,-------......-

.--..'--'I-----.---.-.

...----.....-----------..-.----.,,'j',-

..

-~----~-----,---

·----i-----~-·-~

-----.

---.----1

4R

j!=:

thp.

NllmArir.~IIRI

r.ritF:!ri~

fnr

48

46

14

Lower Lockport Pool

12 I

I

I

I

J

I

t

I

I

I

I I

I

I'

I

I

I

I

I

I

I

I

1

I

I

1

274.4 274.8 275.9 276.5

278.3 279.7 280.5 283.8 284.7 285.1 285.5

,

286.8 287.9 288.9 289.3 290.3 290.5 290.8

292.5 292.5 283.0 295.4 296.4

22

20

~---------------

18

~---------------

16+---------------~---------------------

:: ---------------r-------------------------------I-------------------------------1

I

40 .

38

to

42

are the Numerical

lBi

Criteria for Ohio EPA's Wannwater Habitat Aquatic Life Use

I

38

i

i

I

lJ

~

::

-~~~~~~~~~~~~~~~

.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

,

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

~~~~~~~~~~~~~~~~~~~]

I

;

32

- - - - - - - - - -

-;~ -i~ ;h~ N~~rt~~IIB; ~~i;~ri; fo~

at

EPA~; M~difi~d-~~~;~r-H;bit~;(I;;p~~~d~d;A~~atic-Life-

U~~

----------- j

~

:: :-

I' - - - - - - - -- - - - - - - - - - - --

-:,0

1_ - - - - - - ---- -- _--

1-

--- ----

-- -

_-------t_

- - -- -

j

o

26

---,~-------

'----------------------,-------- ------------------------------- -------------------1

24

/

"\

24

is the NumericallBI Criteria f'1r Ohio EPA's,l\IIodilied Wannwater Habitat (Channel MOd!fied) Aquatic Life Use

I

,

Riv,:ar Milp,

56

Electronic Filing - Received, Clerk's Office, August 4, 2008

---

46 -

Figure 4. Mean 181 Scores Within the Upstream and Downstream 1-55 Segments,

1999.

50 -

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57

Electronic Filing - Received, Clerk's Office, August 4, 2008

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58

Electronic Filing - Received, Clerk's Office, August 4, 2008

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59

Electronic Filing - Received, Clerk's Office, August 4, 2008

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XII. COSTIBENEFIT ISSUES

A significant question to be answered

in the context ofthe current UAA process is: What is the

cost/benefit

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 oflower temperatures

in the Lower Des Plaines River would be negligible in the context

of the 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

Reachwhich 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 Qnality Limits

Based on modeling studies done

as part of the U1W 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,

U1W 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 ofmore

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

operational/technological considerations

of meeting a stricter near-field water quality

temperature limit will be provided by MWGen

as part ofthis UAA effort. Ifthe opportunity is

provided, details regarding this cost estimate can

be presented at a future UAA Workgroup

meeting.

60

Electronic Filing - Received, Clerk's Office, August 4, 2008

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xm. 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