ILLINOIS POLLUTION CONTROL BOARD
    February 19, 1981
    CENTRAL ILLINOIS LIGHT COMPANY
    )
    (R.S. WALLACE STATION),
    )
    )
    Petitioner,
    )
    v.
    )
    PCB 80—89
    ILLINOIS ENVIRONMENTAL PROTECTION
    I
    AGENCY,
    Respondent.
    TIR. WILLIAM B. WOMBACHER APPEARED ON BEHALF OF THE PETITIONER.
    MS. MARY V. REHMANN APPEARED ON BEHALF OF THE RESPONDENT.
    OPINION AND ORDER OF THE BOARD (by J.D. Dumelle):
    Central Illinois Light Company (CILCO) filed a petition
    with the Board on April 24, 1980, requesting a determination,
    pursuant to Rule 203(i)(5) of Chapter 3: Water Pollution,
    that the thermal discharge from its R.S. Wallace Station has
    not caused, and cannot reasonably be expected to cause significant
    ecological damage to the Illinois River. Technical reports
    supporting the petition were submitted to the Illinois Environmental
    Protection Agency (Agency) shortly thereafter. Hearings were
    held on August 12, and September 29, 1980. No members of the
    public were present.
    Part VI of Chapter 1: Procedural Rules, sets out the
    requirements for this proceeding. Exhibit B contains the
    information required by Procedural Rule 602. Based upon that
    exhibit and the evidence produced at hearing, the Agency filed
    a recommendation on November 17, 1980, finding that CILCO
    has made the necessary demonstration.
    The Board notes that pursuant to Rule 203(i)(5), the
    owner or operator of an existing source of heated effluent
    which discharges more than 0~5billion British thermal units
    per hour must demonstrate in a hearing before the Board not
    less than 5 nor more than 6 years after the effective date
    of the regulation (1972) that the discharges have not caused
    and cannot reasonably be expected to cause significant ecological
    damage to the receiving waters.
    The hearings in this case should, therefore, have been
    held in 1977 or 1978. However, given the complexity of the
    studies involved and the lack of any allegations of bad faith
    or dilatory practices, the Board waives that defect.
    40—5 13
    —2—
    CILCO owns and operates the R.S. Wallace Station which
    is a coal—fired, steam turbine electrical generating facility
    consisting of 7 units located on the west bank of the Illinois
    River at river mile
    162.5,
    at East Peoria, Illinois. Net
    generating capacity of the units is 359.3 megawatts (MW).
    Water from the Illinois River is used as the coolant in the
    double pass, open—system condensers. During the period of
    study (1975-1976) the station operated at an average of 24.5
    of gross capacity. At no time during the study period was the
    entire station shut down. The mean daily generation ranged
    from 3.8 to 44.1 of capacity. Units 1 and 2 (38 MW total
    capacity) were retired in 1976. The other units are projected
    to be retired by 1989.
    The station intake volume ranged from 72.4 to 438.3
    cubic feet per second (cfs) and intake utilization ranged
    from 0.3 to 10.7 of the Illinois River discharge. Plant
    discharge temperature ranged from 9.0 to 32.5°C and exceeded
    the ambient river temperature by as much as 8.8°C,
    The thermal plume caused by the discharge of the R.S.
    Wallace Station (~T~5°F, 2.8°C) had a minimum surface area
    of 0.1 acres and a maximum of 3.3 acres measured on the eight
    test dates. The maximum cross sectional area of the plume
    was 10.8 of the river (which occurred at the lowest measured
    river flow). The plume was detectable a maximum of 600
    feet downstream from the point of thermal discharge during the
    winter studies and 450 feet or less for all other measurements
    during the study.
    Under Rule 201 of Chapter 3: Water Pollution, the permissible
    size of the mixing zone is to be determined on a case-by—case
    basis, hut shall not exceed an area of 26 acres nor comprise more
    than 25 of the river cross sectional area. These maximums were
    never exceeded during the field surveys, nor is it anticipated
    that they would be exceeded under worst case conditions.
    Studies of phytoplankton, zooplankton, macroinvertebrates,
    mussels, and fish showed little or no effect upon these hiota
    caused by the heated effluent discharge of the R.S. Wallace
    station, Because the plume occupies only a portion of
    the river’s cross—section an adequate zone of passage exists
    for fish species moving up or downstream. A possibility of
    “cold shock” effects exists, but the small plume area and
    multiple unit design of the station (which makes total station
    shutdown unlikely) would minimize these effects.
    The Agency has not questioned any of these findings
    and has recommended that no further conditions be imposed
    on the operation of the plant. The Board agrees.
    This Opinion constitutes the Board’s findings of fact
    and conclusion of law in this matter.
    40—514
    —3—
    ORDER
    Central Illinois Light Company has demonstrated that
    the thermal discharge from its R.S. Wallace Station has not
    caused and cannot reasonably be expected to cause significant
    ecological damage to the Illinois River,
    IT IS SO ORDERED.
    I, Christan L. Moffett, Clerk of the Illinois Pollution
    Control Board, hereby certify,that the al~yeOpinion and
    Order was adop,~edon the /g7.~ day of-i’
    ,
    1981
    by a vote of
    ~
    Christan L, Moff~j) Clerk
    Illinois Polluti~,~ontro1 Board
    40—515

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