ML20133F847
| ML20133F847 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 06/20/1983 |
| From: | Laird L INTERIOR, DEPT. OF, GEOLOGICAL SURVEY |
| To: | Ballard R Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19264D658 | List:
|
| References | |
| FOIA-85-353 NUDOCS 8508080460 | |
| Download: ML20133F847 (3) | |
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DEPARTMENT OF THE INTERIOR i
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.ater Rsources Division pf,.y 1201 Pacific Avence - Suite 600
!k Tacoca, Wasitington 98402 Oi:
Si June, 20,1983 Q:-
wn.rr f@f Pr. Ibnald L. Ballard, Otief hvirorr.: ental s Bydrologic Ehgineering Branch Q
C:fie of IAclear reactor regulation
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U.S. Huclear Pagulatory Omnission 17 i :
Qshington, D.C.'
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Dear Hr. Ballard:
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Subject:
Freliminary findings on potential Spirit Lake audflew impact on Coltthia Piver and Trojan Ib: lear Plant 4
As regmsted, ve are furnishing you a brief suuary of our prelicitary findirgs on the irpct of a tdficV frcs Spirit lake near K:unt St. Iblens en the
! -i Trojan no: lear p:.er facility. Thcse findirqs are provisical and are sttje:t -
l to review and a; proval of the Director of the crological Survey and therefere i
i should not be released cutside your agency.
l j, l 3.s a result of these findings e reeccund that pu a;7tove s re liaited r:rk in i*.ase II of our criginal proposal--to evaluate sort of the ess'nptiens origi-i
.. ally rade in the =udflow a*.alysis. Ye wuld pro;ose to investigate ft-ther:
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rupsition of sedir.ent frem the rudflcr. during its flow fra: Spirit Lde I1 to the couth of the Cowlitz. O.:r original analysis carried alacst all of f4 the entrained sedlunt to the south of the Cowlitz River. A more realistir
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analysis--folleving the gttern of other atdfica--wuld be to do;csit r
part of this sedinent in 'pnding' areas along the route of the flev.
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this adjtst :nt vill lessen the sedir ?nt deposition in the Coltiia tnd
.1 the calculated uter level at Trojan.
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Slept of sedirant deposits in the Colt.bia River. Can'tal slop of sede.t deposits upstrets of the Ccvlitz following the ray 18-19,1930.aud flev
- 4 vss about 2.5 feet Mr alle--exceedingly flat when compred to similar
,W, flows. The gradient in the Cowlitz River above the toutl,e River fer the 3- -la sane n! flow was about 8 feet per mile. This slope of 0;csit could have D. [
an appreciable effect on backwter and the elevation.sr !'rojan--thus we dI believe this deserves additiccsi analysis.
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The above tw elenents can be easily accomplished within the cViginal wrk
' 'y plan and funding estimtes.
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f, aird 8508080460 850618 3.trict m ief PDR FOIA P CIO T '
BELL 85-353 PDR 0
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PRELININARY FINDIES IN TRGTAN STUDY, FEASE I, June 1983 Miase,I of the sttdy was condteted by l!SCS for the Rxlear'Fegulatory Q>=tission. In Phase I a a:dflow as described in WRI ibport 82-4125 was applied to the Coltthia River, asstning a ntsber of conditions for the utdflow, to determine potential flood elantions at the Trojan Ibelear j
Powerplant. Several scenarios were assited for cenditions in the Gltubia River during and following the stdflow. The flood elevations were deter-mined using the Ocneral Purpose Dax-Freak Flood Simulation n*1 (r.-634),
modified by L. telong (K-599), with the Cbitabia River at several different steady-state discharge agnittdes.
clear Vater Flav Evaluation
- 1. A Covlitz mdflov flood, applied with 'cicar-vater' friction ard no deposits in the Coltubia, did not prcdre peak elevations at Trojan in er. cess of 45 f t, which ITtITfloca design elevation at irojan:
Isak at Trojan = 22 f t with Colu-bia at lov flow a.
b.
reak at Trojan = 38 ft vith Cole.bla in ICG-yr flood it.dflev - Stdinnt D2rosit Iapact &altation
- 2. A Covlit: ntdflov flood, with 'ntriflov* friction in the Coltabia downstreas from the Cbylitz, ' clear-vater" friction upstreas, and no deposits cop exceed 45 f t at irojan during a concurrent r,ajor flood of tha Celtabia, but did not exceed 45 f t during lov flow, slack tide, or less severe (<50-yr) floods of the Cblt'-bia:
Teak at Trojan = 31 f t with mit bia at lov flow a.
b.
Peak at Trojan = 44 f t with mir,bia in 10-yr flood Peak at 1Tojan = 48 f t with mitabia in 100->T flood c.
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3.
About 30 percent of t% r.'et;N tres ti e untz v.mo uc..c4 '..p m -
in the Cbitbia if the D1tabia were at lov flov and slack tide, accor-ding to the routing model.
4.
If 70 percent of the nWflow moving upstreaa vere to deposit, the volua of the depsit v3uld be 500 million ctbic yards, asstning out
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of the Cowlitz a total solids voltae of 2.4 billion cubic yards and 30 percent of that ws ' fines' rer.aining in suspension.
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a 5.
If the gradient of the deposit were -2.5 f t/mi..in the upstreas direc.
I tier., as occurred in thy 1980, the elevation of the 50', :.id & posit woul.d be about 30 ft at the south of the Cowlit.t and about 20 f t at Trojan. Steeper adverse gradients have been observed ano, if Oe) occurred, wuld prodtre higher deposit elevations.
6.
Winter floods can occur on the Coltabia vithin a few days of'lov flovs.
The peak of Deceur 1964, discharge about 1 million cfs and recurrence about 100 yr, folleved within 3 days of a lov flow.
7.
A calulia vinter flo:>d stbsegnnt to 503 My33 depasited tptreu of the Cowlitz at a -2.5 f t/mi gradient during 031t'lia lov flov gg proitre a pak elevatien at Trojan in excess of 45 f t:
a.
Peak at irojan = 45 f t vith Coltrbia in 2-yr find b.
Peak at ?rojan = 49 f t vith Coltbia in 10-yr fimd c.
Peak at trojan = $2 ft with Colt;bia in 50-)r flood
- 8. The evidence frec. Pay-June le80 irdestes tbt a densit, or,ce esto-lished, ray not be secured appreciably in the short terz by elen-nter flow crer the densit.
- 9. The voltne and slope of deposit upstreu from the Ccwlitz are t.M eorc trolling features for Trojan fimd elevations.
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