ILLINOIS POLLUTION CONTROL BOARD

August 21, 1980

CENTRAL ILLINOIS PUBLIC SERVICE

)

COMPANY,

Petitioner,

v.

)

PCB 78—271

ILLINOIS ENVIRONMENTAL PROTECTION

)

AGENCY,

Respondent.

MR

THOMAS

L. COCHRAN, SORLING, NORTHRUP, HANNA, CULLEN & COCHRAN,

APPEARED ON BEHALF OF PETITIONER.

MR

REID NEUMAN, ASSISTANT ATTOPNEY GENERAL,

APPEARED ON BEHALF OF

RESPONDENT.

OPINION

AND

ORDER OF THE BOARD

(by

I.

Goodman):

This matter

is before the Board upon a petition filed March

3,

1976 and deemed appropriate for hearing pursuant to Rule

203(i)(10) of Chapter 3

Water Pollution Regulations

Rule

203(i)(10) provides for Board determination of specific thermal

water quality standards applicabje to artificial cooling lakes

upon satisfactory demonstrations

that the lakes will be

environmentally acceptable

Hearings were held in this matter on

December 1, 1976, January 172

1977,

February 22,

19772 October

16,

1977,

and July 17,

1979.

The subject of this petition is Newton Lake,

an artificial

cooling lake for Central Ilfinois Public Service Company~s(CIPS)

Newton power station which is currently under construction in

Jasper County.

The lake was formed by the construction of an

earthen dam across Weather Creek, which is 1,300 feet downstream

from the confluence of Laws Creek and Sandy Creek

(R 12)

‘The procedure under Rule 203(i)(10) had been simplified by

an amendment to subsection

(cc) subsequent to the filing of the

petition in this case

(See R77-7, adopted on June 28,

1977.)

In

light of the amendment the Board substituted this new adjudicatory

proceeding for Petitioner’s prior regulatory proceeding,

R76—6,

although information from the economic impact study and economic

impact hearing was considered by the Board along with the other

evidence in the record

(Reference to the record refers to the

record in R76-6).

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The lake is required to assimilate the waste heat rejected

from two,

61~—MW

steam turbine—driven generators, which amounts

to 3.36 x 10

Btu/hr.

(R.14).

Cooling water withdrawn from the

intake arm of Laws Creek is applied to the condensers by up to

four circulating water pumps.

The water is heated approximately

22°Fat 100

load and discharged at the Sandy Creek arm through

an open flume 7,500 feet in length

(R.12,

Thermal Demonstration,

pp.1—3).

The lake then operates as a cooling loop, with water

circulating

in a counter—clockwise direction during a cycle length

of 11 days

(R.13,

Thermal Demonstration, pp.1—3).

(This process

is illustrated in Figure 1-3.)

The total surface area of the lake

is 1,755 acres

•(R.12), of which 1,408 are utilized

in the cooling

loop (R.95).

In its petition, CIPS requests that the Board set thermal

water quality standards for Newton Lake which would allow a

monthly average temperature of 102°Fat the outside edge of the

mixing zone and a maximum overall temperature of 111°F(R.13).

An economic impact study prepared for the Illinois Institute

of Natural Resources by William

3.

Stanley & Associates,

Inc.

and

a Thermal Demonstration prepared by the engineering firm of

Sargent and Lundy are part of this record.

Much of the Thermal

Demonstration is speculative in nature because filling Newton Lake

did not begin until the Summer of 1975

(Thermal Demonstration,

p.l—2).

The effect on Newton Lake of the thermal discharge was

predicted in the demonstration by means of a computer simulation

model

“LAKET”

(R.14).

Data derived from other reservoirs, partic-

ularly Lake Sangchris, were used in conjunction with this model to

predict the ecological effects

in the lake

(R.31).

At the July 17,

1979 hearing, CIPS presented a “Final Report

on Preoperational Monitoring”

(Ex.29) and “A Postoperational

Survey of Selected Limnological Parameters in Newton Reservoir

for the Newton Power Plant”

(Ex.30).

These exhibits updated some

of the information contained in the Thermal Demonstration and

included the use of actual instead of predicted measurements of

selected parameters.

The required showing of environmental acceptability under

Rule 203(i)(10)(cc) includes a demonstration of “provision of

conditions capable of supporting shellfish, fish and wildlife,

and recreational uses consistent with good management practices

•

•.“

(emphasis added).

The Board notes that this does not

require the actual presence of either recreational activity or a

fishery.

(See Central Illinois Public Service Company v.

EPA,

PCB

77—158

(April

27,

1978);

see,

generally, R75—2

(September 29,

1975).)

The major questions to consider regarding fish population

capability are:

1.

To what extent will the cooling lake water discharge

create thermal stress conditions for fish and/or organ-

isms in their food chain?

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-a

I-

0~

a-

J

a

C

m

C

C

MJ

a

_________

__________

_________

___________

_________

__________

______/

NEWTON

POWER

STATION

T~4tPMAL

~)tMONSTRATION

FIGURE

1-3

PLOT PLAN OF NEWTON SITE SHOWING

LAYOUT OF PLA~ITFACILITIES AND

CIRCUIATIOH PATTERN OF COOLING LAKE

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2.

Can the populations of such organisms remain viable

despite the occurrence of these conditions?

The computer simulation,

based on an analysis of

meteorological data over the last 20 years,

indicates that

75-100

of the effective cooling loop area may exceed 90°Fduring

late July and August

(Thermal Demonstration, pp.

5—6; Table 4—3

at pp.4—7).

In addition,

it shows that under “worst case

conditions” the entire effective cooling loop area could reach

95°For more for 9 consecutive days

(R.42), which is likely to

cause thermal stress

(R.45).

MoreoVer, populations of nonmobile

organisms may suffer high mortality rates but would be expected

to recover irapidly given naturally high productive rates

(R.45).

However,

fish

and other mobile organisms will tend to avoid such

potentially

lethal temperatures by seeking refuge in the

unaffected area of the lake above the intake point or in the

deeper,

cooler water

(R.45).

The success of the deep water as

a refuge from thermal

stress is critical because its availability would be jeopardized

during “worst case” drought periods

(R.104).

The existence of

deep, cool water unaffected by thermal discharge or extreme

meteorological conditions depends on the occurrence of thermal

stratification,

or distinct layers created and maintained by

temperature—density relationships, although this is normal

for

lakes in the summertime (R~150). The evidence indicates that such

stratification is

likely to occur in Newton Lake

(R.379,462,464)

and provide

a “range of temperatures

for aquatic organisms”

(R.160).

Indeed, the results of the thermal study conducted

during the Summer of 1978 with only Unit One fully loaded

indicates that the stratification is in fact occurring in the

lake, even though the stratification would be less apparent at

the test stations under the partial loading.

The thermal study

data further indicate that the majority of the cooling has been

accomplished at the mid—point of the

loop, with temperatures at

other points tending to stabilize both horizontally and vertically.

(Ex. 35—2.)

Another issue is whether there would be sufficient dissolved

oxygen in the deep water refuge areas to allow fish to survive

there, albeit temporarily.

Despite the increased solubility of

oxygen in cooler water, severe oxygen depletion at the bottom of

a lake is common during the summer months (R.161—63).

This

oxygen depletion is caused by bacterial decomposition of organic

material at a time when normal thermal stratification prevents

replenishment of oxygen to the hypolimnion

(R.161—63). Mr. Gary

Milburn, expert witness for the Agency, contended that a

low

level of dissolved oxygen would be hazardous to fish already

weakened by thermal stress (R.335).

Witness Milburn’s contention

is based on recommendations of dissolved oxygen leve~lscontained

in the “Water Quality Criteria 1972” report of the National

Academy of Sciences.

Mr.

James King, expert witness for CIPS,

while admitting that fish might avoid the deep water due to low

levels of dissolved oxygen (R.53), contended that the deep water

would still be an effective temporary refuge from the thermal

stress conditions

(R.53).

Mr.

James Burkett, expert witness for

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—5—

CIPS,

offered the same opinion, based on experience with other

reservoirs

(R. 472).

The Board notes that the deep water refuge area will be

required

only

under

extreme

and

unusual

conditions

and

then

only

temporarily.

The Board

is

aware

of

the

need

to

protect

our

resources against improbable but catastrophic occurrences.

(See

R.337—38,)

However,

the potential for depletion of dissolved

oxygen at the bottom of Newton Lake does not appear to be a

problem

of

large

magnitude.

The

fact

that

the

lower

depths

of

the

lake may be unsuitable for long term fish habitation does not

mean that a catastrophe results when fish, driven from the

epilimnion by once—in—20—year worst case conditions,

seek

temporary refuge in the deeper water.

The Summer of 1978 thermal study measured dissolved oxygen

concentrations at various depths along the cooling path.

The

results indicate a severe oxygen depletion in those areas of the

lake’s cooling loop which sustain severe temperature

stratification, which appear to be located within the first third

of the cooling loop.

Beyond these areas, the dissolved oxygen

level recovers down through a depth of approximately 5 meters.

(Ex. 35—2.)

Evidence presented by CIPS at the final hearing

concerning a post—operational study made in October, 1978 after

one year of single—unit operation, indicates that fish have

survived the power station’s thermal input in good condition,

and

that changes in populations had occurred not only as

a result of

changing frOm a stream—type to a lake—type environment, but

prior to Unit One’s even going on line and discharging.

Combining the predictive nature of the Thermal Demonstration

with actual,

later temperature measurements and dissolved oxygen

level measurements determined with Unit One on

line,

the Board

finds that CIPS has demonstrated, pursuant to Rule

203(i)(10)(cc)(1), that conditions exist which are capable of

supporting a fishery.

An additional consideration under Rule 203(i)(10)(cc)(1)

is

whether conditions exist which are capable of supporting wildlife

and recreational uses.

The Board finds that these conditions

exist.

CIPS has leased to the Department of Conservation an area

on the west side of Newton Lake for purposes of establishing a

fishing and recreational area.

(Ex.

31.)

Exhibit 33 shows the

fish stocking record at the lake, and Exhibit 34 consists of

Department of Conservation reports concerning the

lake.

Finally,

an area remote to the recreational area has been dedicated as a

prairie chicken preserve, that species being an endangered one.

The issues of technological feasibility and economic

reasonableness under Rule 203(i)(10)(cc)(2) were addressed at

length in the economic impact study and at the hearing of October

16,

1977.

The two major alternatives considered for control of

thermal effluent were wet mechanical

of fstream cooling towers and

trim cooling towers

(R.492).

Both of these options would result

in a reduced thermal output but on balance are less environment—

ally and asthetically acceptable, with respect to other than cooling

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—6—

problems, and cost more to install and maintain (R.494—~7). The

alternative chosen by this petition

(no cooling towers) was found

to be the most reasonable methodology from the standpoint of benefit-

cost analysis

(R.497; Economic Impact Study, Tables 5.1 and 5.2).

The final requirement under consideration is whether

discharges from Newton Lake

to other waters will comply with the

thermal water quality standards in Rule 203(i)tl—4).

Rule

203(i)(10)(aa).

Evidence from the hearing record indicates that

spillover to Weather Creek from the dam will occur at times

(R.36).

Although there is no evidence

in the record directly

concerning present spillovers from the dam to Weather Creek, the

data from the Summer, 1978 thermal study indicate that any

spillover will meet those criteria.

(See Exhibit 35—2.)

The Board finds that CIPS has satisfac4orily demonstrated

that Newton Lake, with thermal

standards of 102°F(monthly

average) and 111°F(maximum), will be environmentally acceptable

as defined in Rule 203(i)(10)(cc).

Therefore, pursuant to Rule

203(i)(10)(ee),

the Board promulgates these specific thermal

standards applicable to CIPS’ thermal discharges to Newton Lake,

and authorizes the Agency

to issue NPDES permits consistent with

this Order pursuant to Rule 914 of Chapter 3.

This Opinion constitutes the findings of fact and

conclusions of law of the Board in this matter.

ORDER

It is the Order of the Pollution Control Board that:

1.

The thermal discharge to Newton Lake from Central Illinois

Power Company’s Newton power station shall not result in a

temperature,

measured at the outside edge of the mixing zone in

Newton Lake, which exceeds 102°Fas a monthly average and 111°F

as a maximum;

2.

The Illinois Environmental Protection Agency is hereby

authorized to incorporate the thermal discharge limitations in

Order

1, above,

in any appropriate NPDES discharge permit.

I, Christan L. Moffett, Clerk of the Illinois Pollution

Control Board, hereby certify that the a ove Opinion and Order

were~adoptedon the

II~,$r

day of

____________,

1980 by a vote

Christan L. Moffe~~f~lerk

Illinois Pollution C5ntrol Board