ML15195A371

Response to NRC Request for Additional Information, Dated May 22, 2015 Regarding License Renewal Application, Environmental Review, AQ-05 on Aquatic Ecology

ML15195A371
Person / Time
Site:	LaSalle
Issue date:	07/02/2015
From:	Exelon Generation Co
To:	Office of Nuclear Reactor Regulation
Shared Package
ML15195A351	List: ML15195A340 ML15195A341 ML15195A342 ML15195A344 ML15195A345 ML15195A346 ML15195A347 ML15195A348 ML15195A349 ML15195A350 ML15195A352 ML15195A353 ML15195A354 ML15195A367 ML15195A368 ML15195A369 ML15195A370 ML15195A371 ML15195A372 ML15195A373 ML15195A374 ML15195A375 ML15195A376 ML15195A377 ML15195A378 ML15195A379 ML15195A380 ML15195A381 ML15195A382 ML15195A383 ML15195A384 ML15195A385 ML15195A386 ML15195A388 ML15195A389 ML15195A390 ML15195A391 ML15195A392 ML15195A393 ML15195A394 ML15195A395 ML15195A396 ML15195A397 ML15195A399 ML15195A400 ML15195A401 ML15195A402 ML15195A403 ML15195A404 ML15195A405 ... further results
References
RS-15-179
Download: ML15195A371 (41)

Text

Memorandum cornfd July 6, 1995 TO: C. W. Jeanblanc

Subject:

Information Regarding NPDES Thermal Compliance for LaSalle County Station In response to your request, enclosed is the complete file of thermal data which has been accumulated by the Environmental Services Department (ESD) for LaSalle Station since 1989. Included in this package are the results of seasonal field studies which were done by ESD personnel in order to establish baseline compliance with the 26-acre mixing zone limitation during varying seasonal conditions.

Based on this data, along with ESD's considerable experience with thermal compliance assessments at our other generating stations, we believe that we have the expertise necessary in order to make informed decisions regarding thermal compliance without the need to perform routine field surveillance.

The Illinois Environmental Protection Agency (IEPA)realizes that continuous monitoring within the mixing zone is impractical, and that is the primary reason why LaSalle (as well as our other closed cycle stations) is only required to monitor and report blowdown temperature (per NPDES permit Special Condition No. 3, Section C).Except during prolonged hot, dry weather conditions, LaSalle's blowdown discharge would not be expected to exceed the 26-acre mixing zone thermal limitation.

ESD has requested that all of our stations keep us informed of the incidence of high intake and/or discharge temperatures, so that we can make further compliance evaluations, as deemed necessary according to conditions. (This includes the potential for additional field studies to document compliance with the mixing zone criteria, which have normally been conducted by ESD, with the assistance of station and/or contractor personnel).

I hope that this information will give you the background you require in order to begin to develop a station thermal compliance procedure, if determined to be required by station upper management.

I would be more than glad to come out to the station to meet with you to discuss this matter further, if you feel that this would be useful.A UWiO=nCOMPan July 6, 1995 C. W. Jeanblanc Page 2 If you should have any questions or require additional information, please give me a call at G.O. Ext. 4468.%P. niak Senior Biologist--ESD JPW:em stemp.mem Enclosures cc: R. H. Varju (w/encl.)M. E. Cole (w/o encl.)File: W-01-PER-H2 (w/encl.)-

MEMO TO FILE

Subject:

LaSalle Station Cooling Pond Blowdown Temperatu-e Summary of Situation:

During the month of March, 1995, LaSalle*s blowdown temperature exceeded 60 OF, as detailed below: 1 of Hours >60a F Max. p21v a F- Max. Uostream 0W March 15 15 69.9 53 March 16 22 68.2 52 March 17 16 67.1 54 March 18 14 63.7 53* Data from Dresden Lock and Dam recorder The blowdown flow rate during this entire period was 32,250 gpm (71.8 cfs). Illinois River flow at Marseilles was in the 9000 cfs range. (Due to the small volume of LaSalle's blowdown, in relation to river flow, immediate mixing can be assumed).

Using the most extreme values encountered during this period, the worst-case, fully mixed temperature of the main body of the river would be: (71.8 cfs (69.9 OF) + (9000 cfs)(54 0 Fl 5 (71.8 cfs + 9000 cfs)This value is well within the 600 F limitation which applies at the edge of the 26 acre mixing zone. This information was relayed to Rudy Varju, LaSalle Chemisty Department.

Station personnel have been requested to continue to call ESD for compliance evaluation whenever the blowdown temperature approaches the monthly thermal water quality standard for the main body of the river.T )Wozniak cc: M. E. Cole R. H. Varju File: W-01-PER-H2 Thermal Study Book August 30, 1993 To: J. V. Schmeltz

Subject:

Thermal Compliance Evaluation of LaSalle Station Cooling Pond Blowdown In response to the numerous reports of blowdown temperatuwes at LaSalle in excess of 90 degrees Fahrenheit over the past several weeks, a thermal plume study was initiated by the Environmental Services Department (ESD). This study was done in order to document LaSalle station's compliance status in relation to Special Condition No. 3 of its NPDES Permit.The subject study was conducted on Thursday, August 26, 1993 by J. Wozniak and M. Cole of my staff, with the valuable assistance of both LaSalle station and contractor personnel.

Measurements taken on this date indicate that LaSalle station's blowdown continues to be well within the limits established by the General Use thermal standards.

Station personnel should continue to keep ESD informed when blowdown temperature exceeds 90 degrees F. Further thermal studies will be conducted, as deemed necessary, to document continuing thermal compliance.

If you should have any questions regardi~n is matter, please contact Julia Wozniak o fys It atQ 0 t. 4468.SupaTisor of Water Quality Attachments cc: R. H. Varju M. S. Tyrrell K. S. Francis File: W-O-GEN-A LASALLE COOLING POND BLOWDOWN THERMAL COMPLUANCZ VERIFICATION STUDY Thursday, August 26, 1993 Pint ODeratin@

Conditions:

Unit 1: 1090 MWe Unit 2: 804 MWe Blowdown Flow Rate: 33,000 gpm (73.5 cfs)Illinois River Flow Rate: 10,800 cfs Ambient River Temperature Data: UDstream of Intake: South Side (1030)S---- 27.8 deg. C 1'--- 27.8 deg. C 2'--- 27.8 deg. C 4'--- 27.8 deg. C 6'--- 27.8 deg. C 8'---xxxxxxxxxxxx 10' --xxxxxxxxxxx AVG>>>>27.8 deg. C Intake: (1045)S ---- 27.8 deg. C V'---27.8 deg. C 2'---27.8 deg. C 40'---XXXxXXXXXx 6' ---xXaxxlxxXX AVG>>>>27.8 deg. C Mid-Channel (1035)27.9 deg. C 27.9 deg. C 27.9 deg. C 27.9 deg. C 27.9 deg. C 27.9 deg. C 27.9 deg. C 27. 9 deg. C North Side (1040)27.9 deg. C 27.9 deg. C 27.9 deg. C 27.9 deg. C 27.9 deg. C xxxxxxxxxxx 27.9 deg. C Discharoe i (1050)30.5 deg. C 30.5 deg. C xxxxxvXxxxxx xxxxxxxxxxx 3XXX0.5 og.30.5 deg. C Downstream River Temuerature (Davmark 248j8): Soeuth Side (1020)S---- 27.9 deg. C i'--- 27.9 deg. C 2'--- 27.9 deg. C 4'--- 27.9 deg. C 6'--- 27.9 deg. C 8'--- 27.9 deg. C 100'--xxxxxxcxxxxx AVG>>>>27.9 deg. C Mid-Cannel (1015)27.9 deg. C 27.9 deg. C 27.9 deg. C 27.9 deg. C 27.9 deg. C 27.9 deg. C 27.2 420. C 27.9 deg. C North Side (1010)28.0 dog. C 28.0 deg. C 28.0 deg. C 28.0 deg. C 27.9 deg. C xxxxxxxxxxx 28.0 deg. C LASALLE COOLING POND BLOWDOWN THER3ML COKPLANCR VUM-PICTION STUDY Calculation of Allowable Thermal Plume: T(amb) = Tm -rOls)uTd-Tifl

[gil) ]T(allow) = T(amb) + 2.8 deg. C where: T(amb)=calculated ambient temperature (deg, C)Qls=Cooling Pond Blowdown Flow Rate (cfs)Td=Discharge Temperature (deg. C)Ti-Intake Temperature (deg. C)Qil=Illinois River Flowrate (cfs)For August 26, 1993 Conditions:

T(amb) = 27.9 -r(7351(30.5

-27.8JU -- 27.9 (10,800)T(allow) = 27.9 + 2.8 = 30.7 deg. C (Definition of Plume Edge)Since the blowdown temperature (30.5 deg. F) is ess than the calculated allowable plume number, there is no detectable thermal plume on this date.

ýA5AL'L COOUwN-a~r

?n Low-Do~t4 T~sft~k RIAE S15 V N=rsck) 14.E 7 x z!c e mr GrF Z.VC- emm' fu'mta (N AU4-rAr GME CWJQbt~lý0 TVMS~ IATS&( titir -M semm)

'-i-j .C..°Si or# ."t's f I)1.F I'* ~ ~~ V* F~I 11. i- J, E R %, I:,'L" .1,. , bf -O UlO J~:41 " , r -J4/i ,*z?*2'I.I-.,-.2.,ri. L I V, E. I LIq ,4 *.::,-'I.

2i. vIjL;I4K lti*-r" U *: HRIV*/. :Si .4IE-B W P RUI b.URE:ii, , ,u ,N[,v.-W D': .0 1 Jr-1 1,, .E .r K Q ? -_ ,IJJD -DNS L:3. P; s !-p*#.IFs Iý,IAL DUE v.A;E. 1ir/,",'?,ýVY H IR UýIRG O.R IG :.i.0F 1, P A r"6 ,.I)MF'! I- I ED)'" "II .,S I.L J ,11.MP1 '%:.TAf'.f]N WI.JALS 'SPECIFIC:

U1E: I'*41i .L .,6 1 1: '- :t-. ,.

PRO ý..l UF THE LLLI.NUI R/VER :,I" C.OCL:IM.,.,') ,,.ri-W)UWN IJUIFALL.IO¶

• , MLXINU ZoNE. rils 't:ED3 10 BE I'ERFI.iMliD TO£t-F;'.-;"l:

• if-.i Ti-iEk.P.MAL LiMITS ARE NOT EXCELLED.-AT4ANUV-

\'190. CUAMLuLA1-VS Reu421 %rdb'TUm -rr L~sA4ET oMAI~ O~ atu;bm"Am %EL-w Wg~ VkLL C20VU"(;C:

WON -nM 00eR \A--TtMl WCW u t N4IO L'Lr1L A's r W, 1 A FRE -JPV a4A E.

January 17, 1990 Tos G. J. Diederich

Subject:

Thermal Evaluation of LaSalle Station Cooling Pond Blowdown In accordance with LaSalle Station's Final Environmental Statement (November 1978, Section 6.3.2.1), seasonal thermal plume measurements were to be taken in the Illinois River at three month intervals for a total of four studies to determine the extent of the 2.8eC (5*F)excess isotherm.

This program was to be instituted after units 1 and 2 went into commercial operation.

At the station's request, thermal studies were initiated in April, 1989.The final winter survey was conducted on Monday, January 15, 1990, by J. Wozniak and K. Owens of my staff. Upon completion of the study it was determined that no measureable 5*F excess isotherm was present on this date.The attached results constitute the fulfillment of Environmental Affairs commitment to perform seasonal plume measurements on LaSalle's cooling pond blowdown (as per AIR Item No. 373-251-89-00079, dated 4/4189).The cummulative data indicates tAat the station blowdown has been in full compliance with the General Use thermal standards on all five survey dates (4/5/89, 7/19/89, 10/16/89, 11/06/89, and 01115/90).

It is recommended that the station install a reliable temperature monitoring device in the blowdown canal immediately before discharge to the Illinois River in order to verify continued thermal compliance.

In addition, Environmental Affairs personnel are available to assist station personnel with the development of site-specific procedures for performing any additional thermal plume studies in the future.If you have any questions regardinq this study, please contact J. Wozniak of my staff at Ext. 4468.P. Smith Supervisor of Water Quality 6841e JPW:bq Attachments cc: K. M. Owens J. P. Terrones C. K. Sprunqer File: 01-GEN-A LaSalle Coolingi Pond Blowdown Winter Thermal Plume Survey January 15, 1990 Pertinent Information" Illinois River Flow: 5979 cfs (Marseilles Lock & Dam)" Blowdown Rates 4$,000-45,000 gpm (89-100 cfs)* Station Operation Unit 1: Unit 2;* Discharge Channel Width:* Discharge Channel Depth:* Discharge Temperatures 815 mWe 1135 MWe 20 ft.2 ft.4.3*C (39.7*F)6841e/JPWtbq LaSalle Coolina Pond Blowdown Winter Thermal Plume SUrvey January 15, 1990 Ambient River Temverature Data: Uistream of Intake S. Side Time (0939)Mid Channel (0937)(. Side (0935)Surface i'29 4'Avg.1.90c 1. 90C 1.90C 1. 18 1.9*C (35.4*F)Surface I'2'4.6'8'10'12'14'Avg.-2.0O*C-2.09C-2,.00c-2,.O~c-2.0*C-2.00C_ 2.0*C (35.8'?)Surface 1'2'4.6'8'10'v.Ul Avg.-*2.l'*C 2.06C-2.OOC 2.0*c*2. OC*2.O*C*2.0*C 2.0*C (3S.607)Inake Time (0941)Surface V" 2'4'Avg.Center of River W 249,J (Downstream of discharge)

(0951)S1.90C Surface -2.0OC-1.89C 1' -2.00C-1.8C 2' -2.0'C 1.8C4' -2.09C 1.8SC (35.2*F) 6' -2.00C 8' -1.90C 10' -l.9gC 12' -__L=Avg. 2.0C (35.69F)6841e/JPW:bg S.-a-a&Waoe cxbRut 0 a I Nou IiM~% R!" A' If.F%:t 2. 4 vxitt~fosbI 2"~ T%" It 4YWMO

-1ýIwfts LAULIZ. CoOIMA P(Mt> B5M*iýa JAWAVN 115,199()(GI = A*A454 N'%.0**-1 3C.9 c 0 1O5 RI VE-)ýx 1.0 0 C, AMOXtMWMr TIOTAL SjgRDMc AM (f %VAR--i'czsvr 0, T" is 'DY v~eJA~f m%$ A V. *./

4 t November 6, 1989 To: G. J. Diederich

Subject:

Thermal Evaluation of LaSalle Station Cooling Pond Blowdown In accordance with LaSalle Station's Final Environmental Statement (November 1978, Section 6,3.2-1), seasonal thermal plume measurements are to be taken in the Illinois River at three month intervals for a total of four studies to determine the extent of the 2.8*C (5*F)excess isotherm.

This program was to be instituted after units 1 and 2 went into commercial operation.

At the station's request, thermal studies were initiated in April, 1989.An additional autumn survey was conducted on Thursday, November 2, 1989, by J. Wozniak and K. Ovens of my staff. Upon completion of the study, it was determined that no additional heat was being contributed to the Illinois River from LaSalle's cooling pond blowdown.

No measurable thermal plume was present on this date. The remaining required thermal survey will be conducted in January, 1990.If you have any questions regarding this study, please contact J. Wozniak of my staff at Ext. 4468.8841e JPW:bg Attachments cc: K. M. Owens J. J. Miller Filet 01-GER-A LaSalle Cooling Pond Blowdown Autumn Thermal Plume Survey November 2, 1989 Pertinent Information" Illinois River Flows 3164 cfs (Marseilles Lock & Dam)* Blowdown Rate: 36,000 qpm (80 cfs)" Station Operation Unit 1: 0 MWe Unit 2: 1130 MWe" Discharge Channel Width: 20 ft.* Discharge Channel Depth: 2 ft.* Discharge Temperature:

12.39d (54.10F)684le/JPW:bg I LaISalle Coojl=-E2Pod Blawdo-yn AUtumn Thermal Ply=e Survey November 2, 1989 Ambient River TeMnerature Data: Uostream o-f- Intake, Time (0932)Mid Chanmel (0930)N. Side Surface 1*2'4.6'8'Avg.13.2"C 13.20C 13. 1*13.2*C 13.2"C 13.2*C 13.20C (55.80F)Surface I'2'4*6'8'10'_I_'Avg.-13.2C-13.20C-13.20C 13.2*c-13.2*C-13.30C-13.30C-13.20C (5S.80F)Surface 1'2'4'6'8'10'Avg'Avg.*13.3*C*13.3*C 13-3*C*13.3"C*13-3*C 13.3*C*13.3*C 13.3*C (5.90V)Time (0950)Su~face -13.10C 1'0 -13. VC 2' -13.10C 1' 13.10C (55.69F S. Side of River!M 249,2 (Downstream of discharge)

(1000)Surface -13.3*C l' -13.30C 2' -13.3'C 4' -13.30C Avc6$8'100 12'Avg.-13.3*C-13.3*C-13.3*C 13.3*C (SS.90')684le/JPW:bg A jl .IL LL1461S ltN% tfp MAP 6%644( SrUlbIt 0 OI Sim uackiNapi IVA ftAmao -M 41"*#4 F~(A~V~ -\w-I _lwl-pLW~%A T AIE; -ýW A wf :~- -~A~V~W~i)

October 16, 1989 Toa G. J. Diederich

Subject:

Thermal Evaluation of LaSalle Station Cooling Pond Blowdown In accordance with LaSalle Station's Final Environmental Statement (November 1978, Section 6.3.2.1), seasonal thermal plume measurements are to be taken in the Illinois River at three month intervals for a total of four studies to determine the extent of the 2.81C (5'?)excess isotherm.

This program was to be instituted after units I and 2 went into commercial operation.

The third of these four required studies was conducted on Wednesday, October 11, 1989 by J. Wozniak and K. Owens of my staff.Although neither unit has been in operation since mid-September, this situation provided a unique opportunity to obtain data which reflects ambient river conditions and associated cooling pond effects upon unheated water. Upon completion of the study, it was determined that the cooling pond blowdown was approximately 2*C lower in temperature than the main body of the Illinois River. This net cooling is explained by the extended absence of heat loading to the cooling pond combined with overlying meteorological effects. An additional autumn survey will be conducted when one of LaSalle's units is operating at greater than 50% capacity.If you have any questions regarding this study, please contact J. Wozniak of my staff at Ext. 4468.6841e JPW: bq Attachments cc: K. M. Owens J. J. Miller File: 01-GEN-A Lafiallo Cgooingt Pond 8lowdown Autumn Thermal Plume Survey October 11, 1989 Pertinent Information" Illinois River Flow: 2435 cfs*(Marseilles Lock & Dam)" Blowdown Ratet 17,500 gpm (39cfs)* Station Operation Unit 1: 0 MWe Unit 2: 0 MW.* Discharge Channel Width., 20 ft." Discharge Channel Depth: 2 ft." Discharge Temperature:

13.4"C (56.10?)* Pool elevation was being revised on this date, therefore only one gate was open at the Marseilles lock & Dam.

t LaSalle Coolina Pond Blowdown Autumn Thermal Plume Survey October 11, 1989 Ambient River Temgerature Data: Upstream of Intake S, Side Time (0947)MidChannel (0444)(0 s9de (0940)Surface 1'2'V 4'60 8'Avg.15.l*C 15.1*c 15.111C 15.1*C 15.l11c 15.10C 15.10C (59.20P)Surface 1'V 24 4'6'8'I00 120'Avg.-15.10C Surface-15,1C 1'-1S.1*C 2*-15.1*c 4'-15.10C 6'-l5.14C 8'-15.19C 10'-1A.= -12.-15.10C (59.20F) Avg.-15.20C-15.14C-15.10C-15.l1C-15.10C-15.1*C-15.10C 15.I*C (59.2C)Time (095O)Surface -15.0*C 1' -14.9gc 2' -14.90C 4' --.14=Avg. 14.90C (58.8C)S. Side of River I d (Downstream of discharge)

(1000)Surface -15.00C 11 -15.00C 2' -15.0C 41 -15.00C 6' -15,0C Avg.15.0*C (59.007)6841e JPWsbg rlcAmre t iSIV4 UXfk'i%*V4 1% ftXnOt4 -M 4YAMOM F1 37 L~A~r-ou, O- LowJDO*~-* __~~-77 JizI 0 4* ------~0 9, (s;: ~9c*4 ~JAZ4T. _________________

~) A~- -. _____ _______I. gll I i IL x lvý-. TC;- -T *B w=* r i V. --_____ ________ ___N__X 1031'&ýr'1 ~ , T~77.I' I~-~ ~ ~ A 5u AM-- of ~ .-- -. ~APV~r~Mi)

July 19, 1989 Tot G. J. Diederich

Subject:

Thermal Evaluation of LaSalle Station Cooling Pond Blowdown In accordance with LaSalle Station's Final Environmental Statement (November 1978, Section 6.3.2.1), seasonal thermal plume measurements are to be taken in the Illinois River at three month intervals for a total of four studies to determine the extent of the 2.8*C (5?F)excess isotherm.

This program was to be instituted after units 1 and 2 went into commercial operation.

The second of these four required studies was conducted on Thursday, July 13, 1989 by J. Wozniak and K. Owens of my staff. Upon completion of the study, it was determined that there was no measureable thermal plume present on this date, (Since the blowdown temperature at the discharge point was only approx. 1oC higher than ambient river temperature, the 2.86C excess isotherm could not be delineated.)

This data indicates that the station's blowdown is well within the limits established by the General Use thermal standards.

If you have any questions regarding this study, please contact J. Wozniak of my staff at Ext. 4468.John. Hughe 5722.JPW: sp Attachments cc: R. H. Kohlmann File: 01-GEN-A Lagalle Cooling Pond 81ovdwn~Summer Thermal Plume Survey July 13, 1989 Pertinent Information" Illinois River Flow: 2450 cfs*(Marseilles Lock & Dan)* Slowdown Rate: 43,000 gpm (9S.8cfs)* Station Operation Unit 1: 1003 We Unit 2: 1006 MWR" Discharge Channel Width: 20 ft.* Discharge Channel Depth: 2 ft." Discharge Temperature:

29.8*C (85.6*F)* Work was being done at the Marseilles Lock & Dam on this date.

)L U-7.7wam" Rosa 04*0 SAW)"#..Vag*wý-Ima "M.to**saw L ok" Coq*" Ue*" AMD ONVU^mt 11 ttk*-Om" ilk, 4r 114, Alk UA-Adl AL_,,W_No Lta#41' Oft'e"A0 F "4r cxlb "Ouse-4-1-ricvovtr..

t ILUMOIS 7-WUK MIXV SooWAt4t, STU101# LOCATIO0 1V~FiGuitri 2.' elm4 tmL-h*,m i% emx-moo -m vmrot4 LaSalle Cooling Pond Blowdown Sunuer Thermal Plum. Survey July 13, 1989 Ambient River Temverature Dat : Upstream of Intake S. Side Time (0956)Mid Channel (0952)). Side (ogs5)Surface 1'2'69 4.Avg.-2g.0*C-29.OOC-29.O*C-29.0"C-29.0"C-29.O*C (84.2*?)Surface 1'2'4'6'8'10o_vg Avg,-29. OC-29.OOC-29.OOC-29.00c-29.00C-28.9*C-28.9*C--2-L=28.90C (54.0*?)Surface 1'4.6" 08'Avq .-28. 9*C-28.90C-20.90C-28.90C-28.9*C-28.90C-28.90C (84.001)jRtAkg Time (0958)Surface -29.OC 11 -29.00C 2' -28.9*C V -28.90C--A* -28.9 Avg. -28.90C (84"F)S. Side of River 2.2 (Downstream of discharge)

(1006)Surface -29.0*C V -29.0*C 2' -29.0*C 4' -29.0C AI' -20Li ( 2 Avg. -29.O*C (84.2*?)5721e JPw: 33P r* A~ -W u M~ --6u9~~ Jeh- ---- -_ _ _ U NA-Cm w T- -_ _ _ I -0 _ ___ __(K * -- ---*J V9Q- '4A100 \~nYdl* f A.4cSn l April 5, 1989 To: G. J. Diederich

Subject:

Thermal Evaluation of LaSalle Station Cooling Pond Slowdown In accordance with LaSalle Station's final Euvironmental Statement (November 1978, Section 6.3.2.1), seasonal thermal plume measurements are to be taken in the Illinois River at three month intervals for a total of four studies to determine the extent of the 2.80C (5*F)excess isotherm.

This program was to be instituted after units 1 and 2 went into commercial operation.

The first of these four studies was conducted on Tuesday, April 4, 1989 by J. Wozniak and H. Bernhard of my staff. Upon completion of the study, it was determined that the station's entire thermal plume on this date covered much less than one river acre and was restricted to the south bank near the discharge point. The 2.8*C (5*) excess isotherm was confined to within 20 feet of the immediate discharge canal. This data indicates that the station's blowdown is well within the limits established by the General Use thermal standards.

If you have any questions regarding this study, please contact J. Wozniak of my staff at Ext. 4468.a a. Hughes 5722o JPW:ssp Xttacbments cc: R9. 0. ohlmann D. M. Lyon Filet 01-GER-A LaSalle Cooling Pond Blovdowf S6rin@ 3zermal Plum1 Srve April 4, 1989 Pertinent Information" Illinois River Flows 16,000 cfs (Marseilles Lack & Dam)" Slowdown Rate: 39,000 gpm (87cfa)* Station Operation unit 1i 1120 MXW Unit 2t 1124 We" Discharge Channel Width: 20 ft." Discharge Channel Depth: 2 ft." Discharge Temperatures 16.10C (61*7)* Avg. River Velocity:

0.8 fps Ambient Riyer Tem~erature Data: Surface 2'4'Avg.Time (1250)-10.50C (50.9*r)-10.4*C (50.7"F)-10.40C (50.70y)-10.4"C (50.7'?)Surface 2'41 6'8'10'12'14'Avg.Mid hAgnaa (1350)p-1G.4*C 1 0.3*C-10.2*C (-10.20C 1 0.20C-10.20C-10014C-10.1IC-10.2*C 50.?'!)50.5'?)so.4 F)50.4*r)50.4"F)50.4"F)50.2er)50.2*r)50.49!)(1315)Surface -10.40C (50.7*?)2' -10.40C (60.7?r)4' -10.40C (50.7?F)Avq. -10.4"C (50.?eF)5721e JPWt sap PT I j Sri L E lip*4ýlwý C.I1 AM .................L~t hWIT~t t.%P*"T~~~i~

&fif M*4St o O Fi&~j~ j:~LL'~r,~

~A' ~STUMM'I -

FlWttri I

• 6TU04 X-Otlknov4 1% ft%.)ý*notA

• TO 4'TAMN

ýl tt..THEsAuz couMEx ?sutc'*A~~4~qs9~'p (Di5Q~or"-let Ros A"1-A~ ~ ~~j~JVO 4-s 3'~j : ~ ____ --_____ ~CA~i)

It I *~111 I!I ~~!ti I:ii I I I I ! I I II I ~ I, iiI'.j I I ~ !.1 I I* I

• j I* KILLIf. 'VIM 'I*

• I I I~ tilt lIt~I ii i 5 3 I I I I S I .Ii *5 4 (1dO.A'c~