ILLINOIS POLLUTION CONTROL BOARD
    June
    22, 1989
    ILLINOIS POWER COMPANY
    )
    (Clinton Power Station),
    )
    )
    Petitioner,
    )
    )
    v.
    )
    PCB 88-97
    )
    ILLINOIS ENVIRONMENTAL
    )
    PROTECTION
    AGENCY,
    )
    )
    Respondent.
    SHELDON
    A.
    ZABEL,
    ESQ., ATTORNEY-AT-LAW,
    APPEARED ON BEHALF OF
    PETITIONER;
    AND
    KATHLEEN C.
    BASSI, ESQ.,
    ATTORNEY-AT-LAW, APPEARED ON BEHALF OF
    RESPONDENT.
    OPINION ORDER OF THE BOARD
    (by J. Marlin):
    This matter comes before the Board upon
    a request for
    variance
    initially filed
    on June
    3,
    1988 and amended February 17,
    1989 by petitioner,
    Illinois Power Company
    (IPC).
    IPC is
    a
    public
    utility
    headquartered
    in Decatur,
    Illinois.
    IPC has
    a
    service territory of approximately 15,000 square miles
    and
    employs approximately 4,600 people.
    IPC provides electrical
    service
    to
    an estimated
    543,000 customers.
    (Am. Pet.
    at
    2).
    IPC
    owns and operates
    a nuclear-fueled electrical generating station
    located
    in
    Clinton,
    Illinois.
    In
    conjunction
    with
    construction
    of
    the
    Clinton
    Power
    Station
    (Station),
    IPC constructed Clinton
    Lake.
    This
    artificial
    cooling
    lake
    was
    formed
    by damming two
    streams,
    Salt
    Creek
    and
    its
    north fork, downstream
    of their
    confluence.
    Water
    is
    withdrawn
    from
    one
    arm
    of
    the
    lake
    to
    cool
    the
    condensers
    and
    discharged
    into
    the
    other
    arm.
    This
    amended
    petition
    For variance concerns the thermal effluent limitations
    imposed upon the discharge.
    IPC seeks
    a variance from these
    thermal limitations until October
    1, 1990.
    A hearing was held
    on
    the petition on April 10—11, 1989,
    at which one member of the
    public attended.
    The Illinois Environmental Protection Agency
    (Agency) recommends
    that
    the variance
    be granted, but disagrees
    as
    to
    the
    conditions
    to
    be
    imposed.
    BACKGROUND
    Prior to the present proceeding, IPC filed
    a petition
    in
    1980 seeking an alternative thermal
    limitation
    From that required
    by Rule 203(i)(4)
    of the Board’s Water Pollution Rules
    and
    Regulations.
    (35 Ill.
    Adm.
    Code 203(i)(4).)*
    On May 28, 1981,
    the Board entered
    its Order providing that the daily average
    temperature of discharges
    shall not exceed 99°Fduring more than
    1Y)—177

    —2—
    12 percent
    of the hours
    in
    a twelve-month period
    (i.e.,
    44 days)
    and shall at no time exceed 108.3°F.
    (IPC
    v.
    IEPA,
    PCB 81-82,
    42
    PCB 145
    (June
    25,
    1981); IPC
    v.
    IEPA,
    PCB 81-82,
    41 PCB 501
    (May
    28,
    1981).)
    When IPC began plant
    testing the Station
    it discovered
    that
    temperatures
    in the discharge exceeded those predicted
    in prior
    studies upon which
    the thermal standards were
    set.
    According to
    IPC:
    Cooling
    water
    (flume)
    discharge
    temperatures
    during the summer of
    1987 were observed
    to be
    greater
    than
    those
    which
    would
    have
    been
    expected
    For
    the
    power
    levels
    being
    experienced.
    These
    observations
    led
    IPC
    to
    conclude
    that
    the
    thermal,
    limits
    in
    the
    Station’s
    NPDES
    permit
    for
    the
    flume
    discharge
    to
    Clinton
    Lake
    may
    preclude
    full
    power
    operation
    oC
    the
    Station during
    a
    very
    warm and dry
    summer.
    r~c
    retained Edinger
    in
    early
    1988
    to
    model
    the
    cooling
    characteristics
    of
    the
    lake
    with
    Station
    operating
    data
    that
    reElected
    changes
    in
    Station
    design
    since
    the
    modeling
    performed
    by
    Edinger
    in July,
    1979.
    IPC also retained
    Environmental
    Science
    and
    Engineering,
    Inc.
    (ES&E)
    to
    assess
    the
    incremental.
    impact
    of
    the
    thermal
    discharge
    on
    the fishery
    of
    the
    lake
    based
    on
    the
    Edinger
    modeling
    efforts.
    The
    modeling
    studies
    confirmed
    the
    current
    thermal
    limits
    were
    inadequate
    and
    the
    biological assessment
    indicated the impact on
    the
    Fishery
    on
    the
    lake
    would
    not
    substantially difFer
    From that determined
    for
    the July,
    1979 modeling.
    (Ex.
    H
    at
    2).
    In the instant proceeding,
    IPC seeks
    a variance until
    October
    1, 1990 from the temperature limitations imposed
    by L~e
    Board
    in
    its
    May 28,
    1981 Order.
    tPC seeks
    to have these
    limitations modified
    to provide
    that
    the daily average
    temperature
    shall
    not exceed 99°FFor more
    than 16.5 percent oF
    the hours
    in twelve-month periods
    (i.e.
    ,
    60 days)
    and
    shall
    at
    no
    time exceed 106.5°P. Additionally,
    IPC
    requests that the
    temperatures
    be
    monitored
    at~ the
    edge
    of
    a
    26-acre
    semicircular
    “mixing
    zone”
    rather
    than
    at
    the
    second
    drop
    structure
    oF
    the
    discharge
    flume
    as
    pr.esently
    provided.
    (Am.
    Pet.
    15-16).
    Rule 203(i)(4)
    is
    now
    codified
    at
    35
    Ill.
    Adm.
    Code
    302.211(e).
    101)—
    178

    -3-
    The Agency agrees
    that
    compliance with the present
    temperature
    limitations imposes
    an arbitrary or unreasonable
    hardship upon
    IPC.
    However,
    the Agency disagrees with IPC as
    to
    the scope
    of relief
    to be afforded under
    the variance.
    The
    Agency recommends
    that the variance be granted for a five-year
    period or until
    such time as the Board acts upon
    IPC’s petition
    for site-specific rule change,
    whichever occurs
    first, provided
    that
    IPC files
    its site-specific petition by April
    1,
    1991.
    The
    Agency also recommends
    that IPC’s thermal effluent limits shall
    not exceed 99°Fin excess of
    56 days during
    a fixed calendar year
    of January
    1
    -
    December
    31
    (as opposed
    to the current rolling
    calendar period) and shall
    at no time exceed 108.3°F.
    Lastly,
    the
    Agency
    recommends
    that
    the
    monitoring
    point
    remain
    at
    the
    second
    drop
    structure
    of
    the
    discharge
    flume.
    (~gency’s
    Rec.
    at
    9-12).
    In
    its post-hearing brief,
    IPC states
    that
    it does not
    object
    to the five-year variance period nor does
    it object
    to the
    fixed calendar modification.
    IPC does object
    to being required
    to file its site-specific petition by
    a date certain.
    IPC
    further
    states that its main concern
    is
    the imposition
    of thermal
    limitations
    rather than the location of the monitoring point.
    Accordingly,
    IPC asserts
    that,
    if the second drop structure
    of
    the discharge flume
    is retained
    as the monitoring
    point,
    the
    daily average thermal limits
    should not exceed 99°Fin excess
    of
    90 days and shall
    not at no
    time exceed 110.7°F.
    The parties
    agree
    that the normal increase in temperature
    across the condenser
    is 19.5°F.
    (IPC Ex.
    H at
    6;
    Tr.
    I
    at 18-19;
    Agency’s Post-H Brief
    at
    3).
    Consequently,
    if the daily average
    intake
    temperature exceeds 79.5°F,the 99°Flimitation will be
    exceeded.
    TPC supports its request for
    a variance with studies
    and models which analyze the weather conditions of
    the summers
    of
    1955 through 1988 and the frequency
    in years
    in which
    a given
    temperature and duration would be expected
    to recur
    to predict
    lake temperatures under assumed operating conditions and summer
    weather conditions
    (frequency
    -
    duration analysis).
    (IPC Ex.
    D,
    B and J).
    According to
    IPC, this data indicates that,
    in
    a
    “normal” summer (i.e.,
    a
    summer which has
    a likelihood
    of
    recurrence once every
    two years or more
    frequently),
    the 99°F
    limitation would be exceeded
    60 days,
    assuming the current
    monitoring point
    and operation at full power.
    (IPC Ex.
    0 at
    39.)
    For purposes of determining the circumstances under which
    Station operation would exceed the daily maximum limitation
    of
    108.3°F, IPC submitted data which predicts the daily average
    discharge
    temperature for a once-in-ten—year summer
    to be
    108.9°F.
    (IPC Ex. D at
    32.)
    In a once-in-thirty-year
    summer,
    the daily average temperature
    at the discharge
    Flume would reach
    109.2°Fon seven
    days.
    (Id.)
    The Agency’s recommendation that IPC he allowed
    to exceed
    the 99°Fdaily average
    for
    56 days
    is based upon an analysis oF
    the summer of 1988 and its effect on Clinton Lake.
    (IPC Ex.
    I,
    I
    fl0-~l79

    —4—
    Attachment 1.)
    The Agency characterizes the summer of 1988
    as
    one of “severe” weather conditions,
    but accepts
    TPC’s data which
    classifies
    it as
    a once-in-eleven or twelve-year summer.
    The
    Agency added the 19.5°Ftypical rise
    in temperature across
    the
    condenser
    to the actual. intake temperatures during the 1988
    summer to determine that there were
    55 days between June and
    September where
    the 99°Flimit was exceeded.
    (Id.)
    The Agency bases its recommendation that
    the maximum
    temperature remain at 108.3°Fon the fact that,
    during the summer
    of
    1988,
    TPC
    had to derate on only two days
    to avoid exceeding
    this limit and this was only because of
    a problem with one of
    three water circulating pumps.
    (Tr.
    I
    at
    51.)
    The parties also differ
    as
    to the probable environmental
    impact of granting the requested relief.
    IPC contends that
    a
    balanced and diverse fishery will
    be maintained
    under
    the
    proposed limitations.
    The Agency asserts
    that the adverse
    effects of continually exceeding the 99°Flimit have not been
    quantified.
    Therefore,
    the Agency proposes that
    a more cautious
    approach be taken
    by utilizing
    its proposed limitations.
    COMPLIANCE PLAN
    The principal purpose of the requested variance
    is
    to allow
    time for IPC to collect data which
    it believes
    is necessary
    to
    make
    the requisite demonstration before the Board
    for a new site-
    specific thermal. standard.
    Consequently,
    IPC’s
    plan for
    achieving compliance with the thermal effluent
    standards
    is
    to
    petition the Board
    for site-specific relief.
    According to this
    plan,
    IPC will collect data during the summer of 1989 while
    operating the Station
    at design conditions
    (full
    power),
    unconstrained by the present thermal standards,
    analyze
    this data
    and prepare the documentation necessary for
    a new site-specific
    standard.
    IPC anticipates
    that
    its petition or
    site—specific
    relief
    will
    be
    ready
    for
    filing
    by
    March
    of
    1990.
    IPC
    believes
    that
    the
    specific
    thermal
    standard
    to
    be
    requested
    will
    be
    the
    same as
    the limitations requested
    in the instant variance
    proceeding.
    IPC considered
    several alternative means
    of achieving
    compliance before deciding upon the plan discussed
    above.
    Specifically, IPC considered
    the alternative supplemental cooling
    schemes of
    a trimming cooling tower and discharge
    flume spray
    modules.
    (IPC
    Ex.
    F).
    These alternatives were rejected by IPC
    because they would require
    the investment
    of additional
    capital.
    According to IPC’s
    study,
    the total capital investment
    for
    a
    coolHng tower would
    be
    S1.3,505,000 and
    S16,2.2’~,O00
    for
    Sj~3~
    fl~UiL1ICS
    .
    (IPC
    Ex.
    F
    aL
    6).
    TPC
    also
    ev~.Li~tLc1the
    desirability
    of
    reduc
    ing
    power
    levels
    to
    maintain
    compliance
    with
    the
    present
    limitations.
    (IPC
    Ex.
    C).
    This
    alternative
    was
    also
    rejected on
    the basis
    of
    cost.
    IPC analyzed the costs associated
    with derating during the summer of 1988 and concluded
    that
    “a
    10.7
    capacity derating coincident
    with system peak demand
    100-ISO

    —5—
    corresponds
    to
    a 1989 revenue requirement
    loss
    of
    $76.6
    million”.
    (IPC
    Ex.
    G).
    The prospect of filing for site—specific regulatory relief
    does not obviate
    the need
    for a compliance plan
    in
    a variance
    proceeding,
    however, the Board has recognized
    that
    some factual
    circumstances prompt some flexibility regarding this
    requirement.
    (Anderson Clayton Foods
    v.
    IEPA, PCB 84-147
    (January 24, 1985).)
    The Board has granted
    a variance
    in the
    absence of
    a concrete
    compliance
    plan where more information
    regarding
    new
    technology
    needed
    to
    be
    gathered
    in
    order
    to
    recommend
    methods
    of
    compliance
    or, alternatively,
    regulatory
    changes.
    (Id..)
    Similarly,
    the Board granted
    a variance even
    though
    a
    petitioner
    did
    not
    present
    a
    compliance
    plan where the
    technology
    did
    not
    exist
    for petitioner
    to reasonably reach
    compliance.
    (Mobil
    Oil
    Company
    v.
    IEPA,
    PCB
    84-37
    (September
    20,
    1984).)
    The
    Board
    concluded
    that
    the
    conducting of research
    aimed
    at
    finding
    a means
    of
    coming
    into
    compliance
    could
    be
    accepted
    as
    a compliance plan.
    (Id.)
    Lastly,
    the Board has
    recognized
    a rare exception to the compliance plan requirement
    where
    the variance requested is of
    a limited duration,
    the
    environmental impact
    is minimal and petitioner has made good-
    faith efforts
    to remain
    in compliance.
    (General Motors Corp.
    v.
    IEPA,
    PCB
    86-195
    (February
    19,
    1987).)
    The Board concludes
    that,
    under the instant circumstances,
    the lack of
    a concrete compliance plan does not bar the granting
    of
    a variance.
    IPC has experienced conditions
    at the Station
    substantially different than those predicted
    in prior models and,
    as discussed below, has demonstrated
    that the expected adverse
    environmental impact resulting from
    its proposed limitations
    is
    minimal
    and temporary.
    Moreover,
    the parties agree
    and the
    evidence demonstrates
    that
    it
    is not reasonable to expect IPC
    to
    immediately comply with the current
    thermal. limits.
    HA..RDSIIIP
    AND
    ENVIRONMENTAL
    IMPACT
    IPC
    contends
    that compliance with the present thermal
    standards
    imposes
    an
    arbitrary
    or
    unreasonable
    hardship for two
    reasons.
    First,
    IPC
    asserts
    that the current limitations may
    require
    it
    to
    derate
    (i.e.,
    operate
    at less than full power)
    without
    any
    corresponding
    beneficial
    environmental
    impact.
    Secondly, IPC alleges
    that
    it
    is prevented from collecting data
    in support of
    a new thermal standard while constrained by the
    present limitations.
    The Agency agrees
    that compliance with the
    current thermal limitations imposes
    an arbitrary or unreasonable
    hardship upon IPC.
    The Agency disagrees, however,
    with the
    relief necessary
    to alleviate this hardship.
    To the extent that IPC
    is contending that the possibility of
    derating
    to avoid exceeding the thermal standards
    in and of
    itself constitutes
    an arbitrary or unreasonable hardship,
    the
    Board must disagree.
    The existence of such regulations presumes
    that, under certain circumstances,
    a power plant may be required
    100—131

    —6--
    to derate.
    The costs associated with derating may constitute
    hardship.
    Additionally, the record does
    not indicate that there
    is
    no adverse environmental impact associated with increased
    thermal disharge,
    but rather that the impact
    is expected
    to be
    minimal in regard
    to the fishery.
    IPC also asserts that
    the possibility that
    it will
    be
    constrained
    in its effort
    to collect site-specific data imposes
    an arbitrary or unreasonable hardship.
    The Board disagrees with
    this contention to
    the extent that IPC suggests that the only way
    to avoid the imposition
    of such
    a hardship is to allow it
    to
    discharge without any thermal constraints pending an
    investigation into the actual effects
    of this discharge.
    However,
    IPC does qualify this assertion by recognizing that
    it
    should
    be subject
    to reasonable constraints designed to avoid an
    adverse
    environmental
    impact
    while
    in
    the
    process
    of
    collecting
    its
    data.
    The Board
    notes
    that
    there
    are
    many
    circumstances
    where discharge of
    a substance
    into the environment
    in order
    to
    study its effects would be irresponsible.
    IPC presented substantial evidence
    in support of
    its
    contention
    that
    its proposed thermal limitations would not have
    a
    significant
    adverse environmental impact on the fishery
    in
    Clinton
    Lake.
    However,
    the Board notes
    at
    the outset that,
    contrary to IPC’s assertion,
    the Board
    is not bound
    by its
    prior
    finding that
    ~‘one-unit operation will not produce unacceptable
    lake conditions”.
    (PCB 81-82 at
    4).
    Just
    as IPC
    is relying on
    updated data and improved modeling
    in seeking higher thermal
    limits,
    the Board may reach
    a different conclusion
    today than
    in
    1981 based upon more current information.
    IPC’s request
    is based
    upon lake temperatures predicted for
    a once-in-thirty-year summer
    as set forth
    in the Generalized Longitudinal-Vertical and
    Hydrodynamics and Transport model
    (CLVHT).
    This report was
    initially
    prepared
    utilizing
    the
    USEPA
    protocol
    for
    assessment
    of
    thermal
    effects
    and
    modeling
    results
    based
    upon
    the
    summer
    of
    1987.
    (PC
    Ex.
    E
    at
    2.)
    The
    report was updated by
    the prepared
    testimony
    of
    Richard
    Hall,
    applying
    USEPA
    protocol
    in
    the
    same
    manner
    to GLVHT modeling results based
    upon data from the summer
    oF
    1988.
    (IPC Ex.
    K
    at 4.)
    The results of
    the CLVHT once-in-thirty-year
    summer study
    were compared
    to the 1980 LARM study which
    Formed
    the
    basis
    of
    the Board’s decision setting
    the present thermal standards.
    (IPC
    Ex.
    K at
    4.)
    This comparison indicates
    that:
    1)
    impacts on
    adult
    survival habitat
    are minimal and similar
    to
    the 1980 study
    for most Representative Important Fish Species
    (RIS),
    although
    habitat
    for survival of channel catfish
    is reduced
    from
    82
    perc~nt.
    to
    Y)
    preent
    end
    survival.
    h~hitat
    For
    w~uit~
    crappie
    dec
    i
    c~ Jul.y
    ~iic1
    A.~gusL
    ~os
    un~vai1.ab1e
    ;
    2)
    L~T1p~ICL~
    ou
    adult
    growth
    habitat
    ace minimal
    and similar
    to the 1980 study
    for most
    RIS,
    but
    less
    for
    carp
    and
    channel
    catfish,
    and
    habitat
    for
    growth
    of
    white
    crappies
    is
    unavailable
    in
    July
    and
    August
    under
    the
    1980
    study
    and
    only
    minimally
    available
    under
    the
    CLVHT
    study;
    3)
    habitat
    availability
    or
    spawning
    was
    not
    evaluated
    100-1~2

    -7—
    during the 1980 study, but under
    the GLVHT study,
    spawning for
    most RIS is restricted
    to April
    and May.
    Also,
    bluegill spawning
    is not available
    in May and June and
    is
    restricted
    in July and
    August and white crappie spawning is not available under the
    GLVHT study; and
    4)
    in general, embryo survival restrictions are
    less severe than the spawning restriction for each RIS and month
    and,
    consequently, the availability
    of spawning habitat
    is
    a
    better determinant
    of impact on RIS.
    (IPC Ex. K at 4-5 Table 1.)
    The specific findings of
    the GLVHT study were tempered by
    several comments.
    Testimony indicates that the evaluation
    represents
    a conservative utilization of USEPA protocol as well
    as
    a conservative approach in
    general.
    in that it does not
    consider what IPC characterizes
    as the “beneficial.
    impacts of
    increased temperatures
    in cooling lakes”
    as demonstrated
    by an
    extended growing season and early initiation of spawning.
    (TPC
    Ex.
    K at
    5.)
    Lastly, while the study indicates
    an impact on the
    available habitat
    of white crappie,
    this species would be
    severely impacted even without Station operation under severe
    summer weather conditions.
    (Id.
    at
    6.)
    IPC also presented expert testimony regarding the inherent
    conservatism of USEPA protocol and the results
    of environmental
    monitoring
    of biological effects
    at Clinton Lake during the two
    summers of Station operation.
    Lastly,
    IPC introduced
    a letter
    from the Director of the Department
    of Conservation
    (DOC) which
    stated that
    DOC had no reason
    to oppose the variance
    (IPC,
    Ex.
    0).
    Specifically,
    the Director opined that, although there were
    three minor
    fish kills on Clinton Lake
    in August of
    1988,
    these
    kills had no significant or permanent impact upon the fish
    population.
    (Id).
    Based upon this testimony,
    evidence and the
    study discussed above,
    IPC asserts that under modeled once-in-
    thirty year summer conditions, operation
    at full power under the
    proposed limitations will not adversely impact on the maintenance
    of
    a balanced and diverse fishery at Clinton
    Lake.
    The Agency questions the accuracy of
    the CLVHT study,
    insofar
    as the summer of 1988
    is
    concerned, because
    of the lack
    of
    inflow data.
    According to
    the Agency,
    the GLVHT study
    inaccurately predicted lake temperatures
    to be cooler than those
    actually occurring in 1988.
    The Agency argues that because of
    this inaccuracy,
    the model underestimates the adverse
    environmental effects.
    Based
    upon this discrepancy,
    the Agency,
    preferring
    to err on the side of caution,
    rejects IPC’s assertion
    that its proposed limitations
    will not have an adverse
    environmental impact.
    The Board
    finds
    that immediate
    compliance with the present
    thermal limitations impose an arbitrary or unreasonable hardship
    upon
    IPC.
    In entering its order
    in PCB 81—82 setting the present
    thermal standards,
    the Board relied upon
    a modeling study
    utilizing the Laterally Averaged Reservoir Model
    (LARM
    1).
    Subsequently, updated models based on plant operation show that
    the predictions
    contained
    in LARM
    1 are
    no longer applicable.
    100—183

    —8-
    Additionally, the data relied upon by the Agency reflecting the
    actual operating conditions
    of the summer of 1988 indicates that
    it
    is unrealistic to constrain IPC to the 99°F/44day thermal
    limitations.
    The primary question then
    is what conditions should
    be imposed under the variance to alleviate this hardship, yet
    maintain the quality of the biological community of Clinton Lake.
    DISCUSSION
    As
    a practical matter,
    Clinton Lake was constructed
    as
    a
    cooling lake.
    It also has substantial recreational benefits.
    The lake
    is not
    a closed system and has substantial impact on
    the
    stream
    it
    impounds.
    Operation of
    the station
    can affect the lake
    and upstream and downstream habitats.
    The ultimate regulation of
    this
    facility must take all these matters into account.
    On balance, the Board
    sees no particular benefit
    to denying
    the bulk of IPC’s variance request.
    The requested limits will
    be
    consistently reached only in
    a worst-case year and
    it
    is
    not
    likely that
    such a year will occur
    during the
    term of this
    variance.
    If such
    a year does occur,
    the expected impact on the
    fisheries
    is expected
    to be minimal and
    is reversible.
    Unlike
    some discharges,
    hot water will not leave
    a permanent residue
    in
    the environment or necessitate extensive cleanup.
    The Board
    notes
    that
    IPC has presented almost
    no information
    on biological organisms other than fish
    in the RIS group.
    There
    are clearly adverse imnpacts on several of these species.
    It
    is
    not clear
    that
    a lengthened growing season offsets impacts
    on
    spawning and
    survival, but the evidence
    indicates that overall
    sport fishing
    is
    not seriously harmed, and
    is in many ways
    enhanced,
    by the expected thermal discharges.
    It
    is ironic that
    the white crappie which make up 94 percent of the sport
    fishing
    catch may be totally eliminated
    from the lake during some years.
    (Ex.
    E.
    at
    34
    and
    114).
    In
    any
    future
    proceeding,
    the
    Board expects
    IPC wIll discuss
    the effect of thermal discharges
    on invertebrates and other
    vertebrates
    as well as sport
    fish.
    Such information would be
    useful
    in addressing overall environmental impact.
    IPC correctly points out that cooling lakes
    in Illinois
    operate under
    a variety of thermal limits.
    It also states
    that
    on the basis of heat rejection rate
    to surface
    area or volume,
    Clinton Lake
    is
    lightly loaded compared to other Illinois cooling
    lakes.
    This discussion does
    not consider several items
    that
    would shed light
    on the equity question.
    Such factors as shape,
    depth,
    location on
    a stream
    in
    relation
    to
    its
    he~dwct ‘rs,
    pe~tL
    LOfl
    of
    1: Lake ~nd outlet,
    and
    ~
    ~nLo
    ar~ out
    ~n
    the
    lake
    could all
    impact
    on
    ability
    to
    dissipate heat
    or
    impact
    the
    environment.
    Given
    the questions raised by IPC,
    it may he wise
    to take
    a
    comprehensive look at
    the whole matter of thermal discharges.
    100—
    1.

    -9-
    IPC presented
    a limited number
    of compliance options.
    In
    reviewing the record
    it became clear that temperature increases
    when one of the three circulating water pumps
    is down.
    The
    provisions
    of
    a backup pump may help achieve compliance when one
    pump needs repair.
    IPC may also wish to consider adding some
    type of heat conducting device
    to the flume
    to passively conduct
    heat from the water and radiate
    it to the air.
    CONDITIONS
    MONITORING POINT
    Presently,
    the monitoring point
    for the thermal limitations
    is the second drop structure of the discharge flume.
    IPC
    proposes that compliance with the thermal standards
    at Clinton
    Lake should be determined
    at the edge of
    a 26-acre semicircular
    mixing zone where the water temperature would be cooler than at
    the present monitoring point.
    The Agency asserts
    that the
    present monitoring point
    should be retained.
    The Agency does not
    recommend use of
    a mixing zone because
    of the accompanying
    regulatory requirements
    and practical problems associated with
    the use of
    such
    a mixing zone.
    IPC’s principal support
    for use of
    a mixing zone
    is that
    the
    Board has incorporated the use of
    a mixing zone
    in prior
    proceedings involving cooling lakes.
    (See,
    CIPS
    v.
    IEPA,
    PCB 77-
    158 and 78-100 consolidated
    (March 19,
    1982);
    CIPS
    v.
    IEPA,
    PCB
    78-271 (August
    21, 1980).)
    However, as the Agency points
    out,
    cooling lakes have varying characteristics.
    There
    is no
    consistent use of
    a mixing zone as
    a monitoring point, nor
    -is
    there
    a consistency as
    to the thermal limitations
    imposed.
    (IPC
    Ex.
    H at 19-20.)
    The Board’s approval of the use of
    a mixing
    zone
    at
    other cooling lakes does not necessitate the use of
    a
    mixing zone
    at
    Clinton
    Lake.
    IPC has failed to provide any compelling reason
    to change
    the monitoring point from the present location.
    As IPC
    recognizes, the primary concern
    is
    that the imposition of the
    thermal limitations be appropriate for the chosen monitoring
    point.
    Therefore, the current monitoring point will
    be
    retained.
    THERMAL
    LIMITATIONS
    IPC
    argues
    that,
    if
    the
    second
    drop
    structure
    of
    the
    discharge flume
    is maintained
    as the monitoring
    point,
    the
    daily
    average thermal limits should not exceed 99°Fin excess of
    90
    days
    in
    a twelve-month period and shall
    at
    no time exceed
    110.7°F.
    (IPC
    Ex. H
    at 22.)
    The Agency recommends
    that
    the
    daily average thermal limits
    shall
    not exceed 99°Fin excess
    of
    56 days and shall
    at no time exceed 108.3°F.
    (Agency Rec.
    at
    11.)
    IPC’s
    99°F/90-day
    limitation
    is
    based upon the “frequency-
    duration analysis” which predicts lake
    temperatures
    for
    100—185

    -10-
    statistically ranked summers.
    (IPC Ex.
    D and H.)
    Based upon
    this modeling study,
    IPC predicts that the daily average thermal
    limits will exceed 99°Ffor at least
    89 days
    in
    a twelve-month
    period assuming full operation and a once-in-thirty-year
    summer.
    Accordingly, IPC’s
    requested relief is based
    upon a
    worst-case scenario.
    The Agency’s recommendation of
    a 99°F/56day limitation
    is
    based upon the fact that IPC only exceeded the 99°Flimit on
    55
    days during 1988.
    While the Agency recognizes
    the need for
    modeling,
    it places less credence on the modeling predictions
    because of
    the occasional discrepancies between the predictions
    and actual lake temperatures.
    IPC argues that the Agency’s position is flawed because
    summer conditions more severe than those of 1988 are clearly
    possible
    so that the limitations proposed by the Agency could
    operate
    to unduly restrain
    IPC.
    On
    the other hand,
    the Agency
    argues that
    there
    are only 92 days between June
    1 and August
    31
    and that
    to grant
    the requested 90-day relief
    is
    to,
    in effect,
    impose no limitations
    upon IPC.
    The Board
    finds that IPC’s criticism of the Agency’s
    reliance upon the summer of 1988 as
    the sole basis
    for its
    recommendation
    has merit.
    Simply because
    IPC only exceeded the
    99°Flimit on
    55 days during 1988, does not mean that identical
    limitations will suffice during the variance period.
    The Board
    is reluctant
    to impose conditions
    with which
    a petitioner cannot
    realistically comply.
    Yet,
    the Board also agrees with the Agency
    to the extent that any permanent relief afforded IPC should not
    necessarily be based solely upon
    a once-in-thirty-year
    summer
    worst-case scenario.
    As previously noted,
    the thermal
    limitations imposed need not
    be so broad as
    to avoid all
    possibility of derating.
    The
    Board
    concludes
    that
    the
    thermal
    limitations
    suggested
    by IPC
    at
    the second drop structure of the discharge
    flume
    are
    appropriate
    for this variance.
    These limits are based
    on the
    assumption that all three circulating pumps
    will
    be operating
    during warm weather unless
    IPC cannot operate
    a pump because
    it
    is not
    in working order.
    The Agency raised questions about
    the
    potential impact of the discharge
    from
    Clinton
    Lake on Salt
    Creek.
    Given
    that thermal inputs will raise lake temperature,
    there may
    be
    a downstream effect.
    IPC will,
    therefore,
    be
    ordered
    to
    monitor
    the
    temperature
    of
    the
    discharge
    from
    the
    dam
    on
    at
    least
    a
    daily
    basis.
    IPC
    may
    choose
    to
    monitor
    selected
    downstream locations
    if
    it believes
    this might
    prove useful.
    \NC
    i-
    I)LJ~A’Fi
    o~
    This
    variance
    will
    expire
    on
    the
    date
    requested
    by
    TPC.
    It
    will allow sufficient
    time For IPC
    to file
    for an extension or
    site-specific relief prior
    to
    the summer of
    1991.
    There
    is
    no
    reason
    to force
    PC
    to file
    a
    site specific by a date certain or
    100—186

    —‘i-
    to
    grant
    a
    5
    year
    variance.
    The
    Board
    notes
    that
    its
    findings
    in
    the instant variance proceeding are not binding on any future
    proceeding for site-specific relief.
    The Board also notes that
    IPC may wish to consider the alternative
    of an adjusted standard.
    CONSISTENCY WITH FEDERAL LAW
    Both IPC and the Agency maintain that the Board may grant
    the relief requested by IPC or recommended by the Agency
    consistent with the Clean Water
    Act.
    (33 U.S.C. sec.
    1251 et
    seq.
    CONCLUSION
    In view of the hardship demonstrated,
    as well
    as the minimal
    projected environmental effects expected during the term of this
    proposed variance,
    the Board
    Finds
    tht adequate proof
    has been
    presented that
    immediate compliance with the thermal limits
    entered
    in PCB 81-82 would impose an arbitrary or unreasonable
    hardship upon
    IPC.
    Accordingly,
    the variance will be granted
    subject
    to the conditions outlined
    in the Order below.
    This Opinion constitutes
    the Board’s findings of fact and
    conclusions of law in this matter.
    ORDER
    Illinois
    Power Company is hereby granted
    a variance
    from the
    thermal limitations
    imposed
    in
    the
    Board’s Order of May
    28,
    1981
    (PCB 81-82) for its Clinton Power Station subject
    to the
    following conditions:
    1.
    This
    variance
    begins
    June
    22,
    1989
    and
    expires
    on October
    1,
    1990;
    2.
    The
    daily
    average
    temperature
    of
    discharges
    at
    the
    second
    drop
    structure
    of
    the
    discharge
    flume
    shall
    not
    exceed
    99 degrees Fahrenheit during more than
    90
    days
    in
    a
    twelve-month
    period
    and
    shall
    at
    no
    time
    exceed
    110.7
    degrees
    Fahrenheit
    during
    a
    fixed
    calendar
    year
    running
    from
    January
    1
    through
    December
    31;
    3.
    IPC
    shall
    monitor
    the
    temperature
    of
    water
    discharged
    from
    Clinton
    Lkae
    to
    Salt
    Creek
    on
    at
    least
    a
    daily
    basis;
    and
    4.
    Within
    45
    days
    after
    the
    date
    of
    this
    Opinion and Order,
    Illinois Power Company
    shall execute and send
    to:
    100— 187

    -12-
    Illinois Environmental. Protection Agency
    Attention:
    Pat Lindsay
    Division of Water Pollution Control
    Compliance Assurance Section
    2200 Churchill Road
    P.O.
    Box 19276
    Springfield,
    IL 62794-9276
    a
    certificate
    of
    acceptance
    of
    this
    variance
    by which
    it
    agrees
    to
    be
    bound
    by
    the
    terms
    and
    conditions
    contained
    herein.
    This
    variance
    will
    be
    void
    if
    Illinois
    Power
    Company
    fails
    to
    execute
    and
    forward
    the
    certificate
    within
    the
    45-day
    period.
    The
    45-day
    period
    shall
    be
    in
    abeyance
    for
    any
    period
    during
    which
    the
    matter
    is
    appealed.
    The form
    of the certification shall
    be as
    follows:
    CERTIFICATION
    I,
    (We)
    ,
    having
    read
    the
    Opinion
    and
    Order
    of
    the
    Illinois
    Pollution
    Control
    Board
    in
    PCB
    88-97,
    dated
    June
    22,
    1989,
    understand
    and
    accept
    the
    said
    Opinion
    and
    Order,
    realizing
    that
    such
    acceptance
    renders
    all terms and conditions thereto binding and enforceable.
    Petitioner
    Authorized Agent
    Title
    Date
    Section
    41
    of
    the
    Environmental
    Protection
    Act,
    Ill.
    Rev.
    Stat.
    1985,
    ch. 111-1/2,
    par.
    1041,
    provides for appeal
    of
    final
    Orders
    of
    the
    Board
    within
    35
    days.
    The
    Rules
    of
    the
    Supreme
    Court
    of
    Illinois establish filing requirements.
    IT
    IS
    SO
    ORDERED.
    I,
    T)orothy
    M.
    Gunn,
    Clerk of
    the Illinois Pollution Control
    Board,
    hereby
    cert
    ify
    that
    the
    nb~ve
    Opinion
    and
    (~rder
    wa.s
    aJopLc~I
    On
    LEe
    ~2
    ~
    (lOy
    of
    -~L~
    ~
    ,
    1~J~9
    ,
    by
    a
    vote
    of
    ~/
    ~-‘
    .
    ~.
    ~
    Dorothy M.$unn,
    Clerk
    Illinois Pollution Control Board
    100—188

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