ILLINOIS
POLLUTION
CONTROL BOARD
June 22,
1979
IN THE MATTER OF:
PROPOSED DETERMINATION OF
)
PCB
78-98
NO SIGNIFICANT ECOLOGICAL
DAMAGE FOR THE DRESDEN
GENERATING STATION
MR.
ROBERT
H. WHEELER;
ISHAM, LINCOLN,
& BEALE;
appeared on
behalf of Commonwealth Edison,
MR.
RUSSELL EGGERT, ASSISTANT ATTORNEY GENERAL, appeared on
behalf of the Agency.
OPINION AND ORDER OF THE BOARD
(by Mr. Dumelle):
On April
4,
1978 Commonwealth Edison Company
(Edison)
filed a Petition pursuant
to Rule 203(i)(5) of Chapter
3:
Water Pollution,
Edison
is asking the Board to determine
that thermal discharges
from the Dresden Generating Station
(Dresden)
have not caused and cannot be reasonably expected
to cause significant
ecological damage.
At a hearing on
August 15, 1978 at the Board~s
Chicago office, the Agency
indicated that it
did not oppose Edison~s request.
On
November 16,
1978 the Board remanded this matter for additional
information.
On May 15,
1979 Edison filed a supplemental
report,
This proceeding
is governed by Part VI of the
Board~sProcedural Rules.
Dresden is a three unit, nuclear powered,
steam electric
generating plant
with a capacity of 1795 megawatts
(MW) net.
The plant is located
eight miles east of Morris, Illinois in
Grundy County at the
confluence of the Kankakee,
Des Plaines,
and Illinois Rivers.
Unit
I began operation in
1960 and has always employed
an open cycle, once
through condenser cooling water system.
This unit withdraws
426 cubic feet per second
(cfs)
of water
from the Kankakee and
Des Plaines Rivers,
raises the water
temperature 16,6°Fat full
load, and
discharges
into the
Illinois
River one mile
downstream of the intake,
Units
2 and
3 began operation in 1970 and 1971 respectively
and use a closed cycle,
spray canal/cooling
pond system for
cooling.
During the months of October—April this system
discharges only 111 cfs to the Illinois
River and withdraws
156 cfs from the Kankakee and Des
Plaines River,
The difference
(45 cfs)
results
from
evaporation and seepage
from the spray
canal/cooling pond system.
The closed system raises the
cooling water 21,4°Fat
full
load,
This water
is discharged
through
a two mile canal using
68 spray modules, pumped into
34.—37
—2--
a
1275
acre cooling pond and circulated for 2.8 days, discharged
into another
two mile canal
using
30 spray modules, and then
recirculated
through
the
condensers.
From
May-September
the
discharge
to
the
Illinois
River
ranges
from
111-1115
cfs
to
avoid
severe
megawatt
deratings
from
high
water
temperatures
and
excursions
above
the
Board’s
thermal
water quality
standards.
During 1972-1976 the capacity for the entire plant
ranged from 41.5—72.2
with an average of 54.8.
No 1977
data were presented.
Future capacity is expected to lie in
the 60—65
range.
Unit 1 will probably be retired in 1995,
unit 2 in 2005, and
unit
3 in 2006.
No additional units are
planned at the present time.
Shutdowns
have
ranged
from
a
few minutes to several months with at least one
unit running
at all times from 1972—1976.
Forced outages are expected
10
of the time for 1978—1982 with an additional 10—15
for
scheduled
unit
refueling maintenance overhauls.
The temperature of the discharge from the Unit 1 open
cycle system has ranged from 32.7°Fto 100.1°from August,
1972 to November, 1977.
The discharge from Units 2 and 3
has ranged from 43.7—93.3°Ffor the same period.
Forty—nine actual plume studies have been con4ucted on
the combined effect of
both
discharges with approximately
one
half of these studies done during the warm
summer
months.
Seven studies were conducted when the Illinois River flow
was less than the 7 day,
10 year low flow.
Calculated plume
size has ranged from 0-24.6 acres, all within the limitation
of 26 acres in Rule 201(a) of chapter
3.
These plumes have
covered less than 10
of the width of the Illinois River on
an average.
A
maximum
zone of passage is said to exist
because of the tendency of these plumes to occupy thin upper
layers.
Edison has not been able to find any mathematical model
which can adequately pre4ict typical
and
worst case con4l.tjons
or
which
identifies isotherms at 3°Fdown to ambient temperatures
for this physical configuration.
Edison feels that fle
complex physical conditions existing in the vicinity of
its
discharges
make
all existing models inapplicable. Specifically,
the different velocities and temperatures of the Des Plaines
and
Kankakee
rivers, the fact that the Des Plaines is almost
isothermal while the Kankakee exhibits marked stratification,
and. additional complications such as barge traffic result in
calculated plume sizes
which
are smaller than the actual
recorded plumes.
Edison has collected extensive biological data from
1969—1976 on
the
quality of the receiving streams both
upstream and downstream. Water quality was somewhat improved
as a result of Edison’s operations. The benthic community
near the discharge points was affected more by factors other
34—38
-.3—
than thermal
additions.
Phytoplankton and zooplankton do
not appear to be affected at all while effects
on the periphytic
algal community were
localized around the immediate discharge
area.
Similarly there were
no observable adverse effects on
fish populations.
Edison
feels that the
riparian habitat in the area is
the primary factor controlling populations of wildfowl
and
amphibians.
Edison points to a greater diversity of ducks
and geese
in the cooling lake than the Illinois River.
Since there is a greater temperature rise in the lake,
Edison feels that no adverse effects on wildfowl would be
observable
in the Illinois River.
None of Edison’s sampling
has revealed any impact on amphibians
in the vicinity of the
discharge.
Edison points
to an
increase in recreational boating,
a
possible beneficial impact on
fish populations,
and a lack
of any adverse data to support
its conclusion that the
thermal discharge
from Dresden has not interfered with
recreation,
While Edison’s data has not completely conformed with
the letter of Part VI of the Procedural
Rules,
it has shown
that thermal discharges
from Dresden have not caused and
cannot be reasonably expected
to cause significant ecological
damage to the receiving waters.
This conclusion
is
supported
primarily by Edison’s evidence which shows that it has
complied with present standards through actual data.
The
fact that wildfowl seen to prefer the cooling lake to the
river is probably attributable
to the habitat of the cooling
lake and not to any thermal component.
The lack of theoretical
data required by Procedural
Rules 602(c)(2)
and
(3) will
have
to be cured when Edison requests alternative thermal
effluent limitations under Rule 410(c) of Chapter
3: Water
Pollution and Section 316 of the Clean Water Act as
it has
said it would.
This Opinion constitutes the Board’s findings of fact
and conclusions
of law in this matter.
—4—
ORDER
It
is the Order of the Pollution Control Board that
Commonwealth Edison Company has not caused and cannot be
reasonably expected to cause significant ecological damage
to the Illinois River
from the thermal discharge
from the
Dresden Generating Station.
Mr. Goodman abstains.
I, Christan L,
Moffett, Clerk of the Illinois Pollution
Control
Board,
hereby certif~’the above Opinion and Order
were
adopted
on
the
_________________
day
of
~Jw~4~
,
1979
by
a
vote
of
4—b
Christan L.
Moffett, ~1~rk
Illinois Pollution Control Board
34—40