HomeMy WebLinkAboutBradley Lake Completion Design Report 1992··-Aiasic.a ~n~rgy Auth ority
COMPLETION DESIGN REPORT
BRADLEY LAKE
HYDROELECTRIC PRO J ECT
FEDERAL ENERGY REGULATORY COMMISSION
PROJECT NO. P-8221-000
Prepared By
STONE & WEBSTER ENGINEERING CORPORATION
JANOARY 1992
.j.
·, )v "!-., .
~"' ~
.,_!, DONALD E. BOWES
CONSULTING ENGINEER • 16225. S.E. 29TH ST. • BELLEVUE, WA 98008 • USA • TELE 425-562-6093 • FAX 425-641-3747
LEITER OF TRANSMITTAL
TO: 5-/-q.,., · S1'ec z /(ow sl<'i PSA:
AEA File:
Project: f3~d/e~ 1 1( ..
Date: 3 /?..t:t /99
WE ARE SENDING YOU ~closed D Under separate cover via--------
0 Report (s) D Drawing (s) D Data D Diskette (s) D Specifications
D Letter (s) D Calculations D ---------------~---
COPIES DATE , NO. DESCRIPTION
See re./)l:'r--4 r .·~ _,. 0"'\ I e++t~~" Y9 1~'~
Q. Hct G ~ e.d 1 ·
Sh·jpW\e.V\.-t ftl') -I-1.4Jo bov.e..s.
THESE ARE TRANSMITIED as· checked below:
D For approval
D ~s requested
BReturned
D For your use D Reviewed as noted
D Returned for corrections D For review and comment o ____________________ __
COMMENTS:_~--~-----------------------
COPY TO: __ ___;_ ______ ~--SIGNED: _{J)_· _· ~____;__03.___;:_--'CJ.-' _4 ~-~-------
. , --
G. WILLIAMS, Inc.
·· January 9, ·1999
Donald E. Bowes, P.E.
16225 S.E. 29th Street
Bellevue, WA 98008
Subject:
Dear Don:
Bradley Lake Hydroelectric Project
FERC Supplemental Report
P.O. Box 876688
· Wasilla, AK 99687
Phone (907) 376-9035
Fax (907) 376-9036
Transmitted herein are the following documents for you use in preparing subject
report.
1. Final Construction Geology Report, Bradley Lake Hydroelectric Project,
Volumes 1 & 2, May 1991, Bechtel Corporation.
2. Bradley Lake Hydroelectric Project, Project Construction Historical Report ,
Volumes I & II, Alaska Energy Authority.
3. Completion Design Report, Bradley Lake Hydroelectric Project, Stone &
Webster Engineering Corporation, January 1992.
Please return these documents when you are finished with them. Please contact
me if you have any questions.
Sincerely,
t~
Remy G. Williams
cc Stan Sieczkowski, AEA w/o transmittals
Jim Thrall, MMI, w/o transmittals ·
'
... .,_ ·-•• ·-
'
U NITED STATES
DEPA RTMENT OF THE !NT~=·~=
GEOLOGICAL SURVEY
j ·' ~4-,t ,j:--:-·
~-~ ·~
•
\
KACHENAJf
BAY
J•
I 1 ...,.
"'-L
•
'·
.. r-
1.
I
1 +
I
' ~
I
-J
• . ....
(
l
•
r
I
I
i --~ 4--,_-J
I / •
1
..L
•
4..
' • r ><~ : ' -.: . . "'
-
r . \
\
!
...1
\
I
. "' "-1 '
•
" •
)
\•
j
"
I ;.,
'
••
35
D .,_
"
25
36
?
n -., ..
,,
C·~·~--~~--------~
• • ~
'
11
Si: L[X. \ff_t., lD· UL1A· RAN....,LE UNITED STA TES
A.LASI<~ i<t.NA ~ 1JN ~A IHOEPA ~Ti'o~E NT OF THE: INTERIOR
I s~ \ Tl poor; A PHI GE.U LOG ICAL SUR VE Y
" 1'!1(··~ 1ft" IIIW f21/Doo[~-fK E: NA I A :.IJ
) . ...,.. • l<J
U.S. Geoloeical Survey Stream-gaee Network-Bradley Lake Hydroelectric Project
SEllX>VIA •0-2) QU ADR AN GLE
AlASK A -KF NA I PENINSUlA BOROUG H
1.(-3 ~ SlRIES CT"OPIX:PAPt'OC l
25 -u 10 .0: ~ m 15C1'2111T60'1:)}
10/30/91 I ~·· .-. --
Soil Conservation Service Network (Snow Measurement s) October 30, 1991 (S-River Stage, P-Precipitation, A-Ambient Temperature, W-Water Temperature, lG-Intragravel Water Temperature, V-Battery Voltage)
Station
Nuka Glacier
De sc r ipl iun
-Located adjacent to U S GS Stat ion # 15238990, Upper
Bradley River near Nuka Glaci er at approximately the
same elevation.
Station No. Station Name
Upper Nuka River near Park Boundary
Upper Bradley River near Nuka Glacier
Bradley River near Homer, Alaska
Bradley River below Dam
Latitude Elevation 11 Parameters
s, p (''),A, v
S,A, V
calculated
S, P ('),A, W, V s
Middle Fork Bradley River-Located adjacent to USGS St ntion # 15239050, Middle
Fork Bradley River a t a p proximately the same
elevation.
15238648
15238990
15239000
15239001
15239050
15239052
15239070
15238982
15238984
15238985
Middle Fork Bradley River 2/
Middle Fork Bradley River Division 2/
Bradley River near Tidewater
Battle Creek below Glacier
5941'04"
59 42' 03"
5945' 30"
5 ~4 5' 30"
59 46' 42"
59 46' 05"
59 •18' 06"
59 44' 19"
59 45' 10"
59 45' 23"
Longitude
ISO 42' 12"
150 42' 20"
150 51' 02"
150 51' 02"
15 0 45' 15"
150 46' 59''
)50 52' 58"
150 53' 49"
!50 57' 12"
150 57 ' 08"
1300 ft.
1190 ft.
1054 ft.
1054 ft.
2300 ft.
2200 ft.
25 ft.
780ft.
)()()ft.
90ft.
S, P ( .. ),A, V
S, P ('),A, W, IG, V
s
South Fork Battle Creek s s
Both stations collect snow pack , temperature (niaX , min , a vg) an d precipitation.
Rain gages are mounted inside a Wyo mmg sh iel d tJt ihzing methanol/glycol
displacement. 1/
21
Battle Creek near Tidewater
Elevation are NVGD [rum topographic maps, except Bradley R1ver below dam which is from AEA survey,
7
18
19 20
10
, :-~)~~~
~~ ! ~~ •'
L.
I
l.
16
'<
..
l
11
' I
.l
I
l
I
1-
' \ ' .
IS l"
"
t
" I
I v;: .......... i
In
·,
•
••
' •
. '
'
"
1J ••
. -
• ••
Gage will be established on the M1ddle Fork Bradley River DJVersion once the channel stabilizes.
gages will be installed early Summer 1W2.
Ambient temperature and precipitation
Rain gages are in place, but not yet wired for electric heat.
Raingages mounted on towers utilizing methanoVglycol displacement will be insta lled early Summer 1992 .
All Nuka and Bradley River stream stage instrumentation arc FlUid Data water Gage ll's with CR-10 primary datalogger and analog backup
recorder. River stage, precipitation, and ambient temperature are transtmtted vm RTU. Water temperatures arc not transmttted. AJ1 dala ts
stored in the USGS WATSTORE database.
Battle Creek below Glacier utilizes a mercury STACOM manometer hooked to a Fisher-Porter digital recorder with a analog backup recorder.
South Fork Battle Creek and Battle Creek near Tidewater both ultlize a Datapod recorder co upled to a submersible pressure transducer .
l -I
BRADLEY LAKE HYDROELECTRIC
1 n: \ , I, .. I y ...
::Ul \ ~ ~ >o -:¢. t t ,.~ "-;-4 I f
PROJECT -USGS S t ream Gage
sites
·. r L 1
"
' o\ •
' '
'
Y\ ';
I / ,.
r
'
jO
,,
•
•
'
I
•
, < I
t
t
" '
. , ~., l : ; , , } t , -L If ·?
~ ........: t •/. l ~ --r -.. 1 ... ..,.. . ...
l ~ ....
' '
"
1
13
r
• '
"
'
0
••
-~ I
I l
' •
I
t --1·
l
,,
'
, .
/ •·
\. ..
) i
!'
•
···-l
I I ,,
·t'
' I
t
--~--·~-
I
l
~ r
."J_ .. . I -
"
L, -,. -.,.
l I
...., ~~r
15
Q f)
j
\ ... I
., ,•
'
• t6 l 3~
,, -'I ( --} -·~=0-i-~--,K ~----"'~·, ~'~. ,:,;,11"""-~(+--
' 'BRADLEY RI VER '
I 1523905 0 ,' Cl "l ' /" ~t.
• I
) l'
I
,.
\\ . I • >
",;., ·-. '"" '
! ~-...
' . ,• ·.
. ' ·-> '\ ,,
/ . ~
"'"'
'• K f
~\,,,--
• '1 UPPER BRADLEY RIVER ' -
• NEAR NUKA GLACIER _ • ~-~~ \
15238990 '
I ( •
I ~ ~ J ',\
) KE 1 NrA :::_t ~-
UPPER NUKA RIVER '1
••• NEAR PARK BOUNDARY l,,
15238648
.. ,
' '
'
,.~\.r --
J I·
.(~ \ ~~
\
1 v
~"~ (' \I
[, I~ 1 ' I
' ' I I \I '
}, ..... '} .
'
•
• ·' . .
'
"
l
I
' ' ' / "i..\l 'W ):l~mrl. '{J h+ '\I
\ ....
"
" 'I 0 1.)
-,
)
"
' ,. -.,.
\
.v
..
I
I
OS, \ 't" ...
l-1 ..
t
·I
1
(
f "
1\
\
' -'-
\. \
-,
/ ,_
•
\
I
+ ,
'·
I
I.
j
'
'
KE NAJ
'
l
' '
'
:t" ____ )~ -. r-----.. r -",1
,
' h\ I
J c-..wo.'•
I II r /41,{
11
I ( : '!;ff::l ' .r , f..l.1, T1Qlo,A (. ..._.lfOOSit t' lANG£
,;; ,_ 11'·
l
.,.
' \
I ,_ " .. ",
I
f
,/
j.,
I
.. "' ...
+ t
j
. -:i..··~ ... I
. r ~-~ '"l
7. '
~
~ , . rc\-
• ;r• •
//
;
-'
\ >,I
.). ,~·-
30
31 32 33
t
'
~
1
\; • 9
35
'
.,.. ..... • I
••
r
•( :"
'
'I
..
.-•
I
,1
\
Storm M tn
. ...
)
t/.iJ r
1
I c
I
j
I ../ ' '
t
< /
I I
y . -,.,
":"t -. '
/
'
... +
I
'· j-
. ...L
' Po lo! I I
TOf.q••rt-1 """',-'~«Wtt''GGI'Imm .... l ~·-
r.loetl i 9'S 1 tot ~ """-cfllct,ed
s.llc•l!d Mo!l•,.-•..,~ !IN~ lotn> USCf.GSC~t<t~8~1
{19'lll tl':o~ i 1952), ~ ij~~ (l!ii!UJ {1200 oco tcaltl
r~~ "~<>"IS !'a! ,~~.,.,..·~~..,.,.;>,.<W$f't
t: .... rjal ,,.,.,..,. "'-~"' ;"'~J!'t:-on 1""1~ '~""~ ..,.,.,n~ ~ :m
lt OC(l.~ox• i'od :..= ........ ~ :-7.."::-·~ 11$~ 10' .. 4
}'_((.~·· ;.11> "1!'$1:1 ••"S~ .. ~_.rtoo i"'.'>CII .. .,~ .. -...
~·, • . ..... "'P"'¥ ~... --,.•ad ·-
~~ ~ "• ! Oft llf .I'"IC "''~'"' rQO suo. s.o-~ .. ~~ ...... oo,..
~--~ r.e """""""·-~ .tr,-tll>'"f~tl.n~f'Q :11'1-~'0"lll.l£'"~''
.U r-Ift jilj ,.-, .. ~ Peel
........ ~~I be, ·""~ ftiiO'dinp ,..,., ~ 1111 tll!U ....... Cll :1M.,,. -Ill' Str.• =-::!lr.:!. ._an lfll$ !!lap
'
15
~I
I l \. . ·'
l ' r ~-,. 19
I I .. • 26 30 25
.J~~~~~ '"'H ~ ,r.w llllOO IIU) IXIOI) f~ '+'"'+' II'XIIo : (ll[T
'•...ooo••ou
dJt.jT(lJft INTfPV .\1.. 100 F££l
""''~lit(WJ(l'(;<;£11, ..... _ ~'"""" 1919
Q.Oii\'U .~ >!!~ ·>'!''"!II '"L'-0! 1.0WIR !.OW l'•'i~
• -"' ... ~ .. 11"" .. ....._ ....... ! •1101:, ....... -""'' ...
-~-Of 1 .. OS ....0:: ""'!1• LioiU.I
fOR SAL E B Y U.S G£0lOGICAl SU~V£Y
fA.IRSAHI<'S .e.l)o.SKA. 99701. D£NVER.COLORA.DO B022!i,OR f!f SlON.VIR<;I r..l" 22091
~ ULD£A OlSCAIIIII<G TOPOGA~~IC o,l ~f>S ""'0 Sl..aoi.S 1$ ~V~I -!It[ ON RlQVUT
' '
' <
'
r'
\. I
~t
,
I'· • . . '
,
\
'
.•"' --•
l
. )
/
·'
r
,..
I '
\' '.
~~ )
~.,---~-'~'-·-•"_....,-'--'-~'L
1~45
b, l ,,, olnd IJ!£
IIOlO CLJ,SSif(:l liON l'!f....-fllh, ~ frDm UX.&C~ dllrb 86JO
fld 855.2 c 1 zoo 000 ~.w,
~ ....ts ·If titi.IJ: -.s -llDOII·~ '""' ..... ~·,.·~.., ...ttllib ~ ~
.... pll(lUW.ooll! flert '~"'t
-,,.., • ...,"' Met-,t., PO!I!(hQQ ,c,.,. '$
lFfl< Ao-.... ~
............ llnt.ollt_,_
SELDOVI A (C 3). ALA SKA ...-.t •' 1 ,...,..,e<c•• •'"''("'
N5930·-WI504:./ISX22 5 ;>o ~ -"'-• "'-
' ~·f -1 Hlt
' ' Mt ,O..bio
J
'
\
)
r .. Wil...
. J• -· ..
• J
......
. .
. . .
a-.M-t t.
lsloo• •• ..
1$f:l00VIA 8 .-1
'SeAl r 1 F.lJOO
' ..
...
:..--..I -,..,;.' .,..===wa·o-c--
,,~
' ·---~
COI<IOOfll Hfl'l'oAt. 1l"l 'ft
,..... IlK . • <r
l.l!-' i -.-[ n• ,.,
_,-·~t•' I
.... ""' ......... J "''""
I 1< .. 1 .. ~ ............. ..
FO R SALE B Y 0 s GEOlOOI.:At. S:.MVCV
,. £ liJlll llll'l rtO
~~
OfNVER t. COLORADO W,ot,SHINGTCN 25, 0. C .
• • .r
,
c ) I I
I
(
\.
,,.
. ..
... .., .. .,
ON
I
/
......
I
I "''" JS0.2230'
...... <<b..
" "'· ~
SELOO VI A (C-2). AL ASKA
p -1 ~d 'J Pie tron 19~}
COMPLETION DESIGN REPORT
January 1 992
BRADLEY LAKE HYDROELECTRIC PROJECT
FERC PROJECT NO. P-8221-000
ALASKA ENERGY AUTHORITY . . . ···;~· . ··.·
(
\ ...
(
' ---( \
COMPLET~ON DESIGN REPORT
TABLE OF CONTENTS
1.0 PROJECT DESCRIPTION
-./
1 . 1 Site Climatological Data
1 .2 Design and Construction of Project
2.0 GEOLOGIC SETTING
2.1 Regional Geology and Tectonic Conditions
2.2 Overburden
2.3 Bedrock Materials
2.3.'1 Graywacke
2.3.2 Argillite
2.3.3 Chert
2.3.4 Dacite.
2.3.5 Metatuff
2.3.6 Greenstone
3.0 SUMMARY OF DESIGN
3.1 General Design Parameters
3.1.1 Earthquake (Seismic) Design Criteria
3. 1.2 Tsunami Hazard Evaluation
3.1.3-Reservoir Sieche Hazard Analysis
_ 3.1.4 Project Hydrology
3.2 Main Dam
3 .. 2. 1 General Description
-3.2.2 Stability Analyses, Assumptions and Results
.3.2.3 Construction
Page No.
1-1
1-2
2-1
2-2
2-3
2-3-
2-4
2-4
2-5
2-5
2-6
3-1
3-1
3-3-
3-3
3-4
3-10
3-10
3-10
3-.13
3.3 Spillway 3-14
' \ 3.3.1 General Description 3-14
'. '
3.3.2 Stability Analyses, Assumptions and Results 3-14
3.3.3 Construction 3-19
3.4 Power Tunnel Intake and High Pressure Gates 3-20
3.4.1 General Description 3-20
3.4.2 Design Parameters 3-21
3.4.3 Construction 3-21
3.5 Power Tunnel 3-22
3.5.1 General Description 3-22
3.5.2 Design Parameters 3-23
3.5.3 Construction 3-23
3.6 Powerhouse 3-25
3.6.1 General Description 3-25
3.6.2 Stability Analyses, Assumptions and Results 3-26
3.7 Diversion Tunnel 3-28
( 3.7-.1 General Description 3-28
3.7.2 Design Parameters 3-29
3.7.3 Construction 3-30
3.8 Other Project Structures 3-30
3.8.1 Diversion Structures 3-30
3.8.2 Transmission Lines 3-31
3.8.3 System Stabilization Equipment 3-32
4.0 START UP
4.1 Initial Reservoir Filling 4-1
.4.1.1 Settlement Survey Monitoring 4.;1
4.1.2 Spillway Seepage Monitoring 4-2
4.1.3 Visual Inspection 4.:2
4. 1.4 Diversion. Tunnel Performance 4-3
4.2' Initial Power Tunnel Filling 4-3
I' 4.3 Powerhouse 4-4 (
\
Summary
Test Organization
Schedule
Results
4.3.1
4.3.2
4.3.3
4.3.4
4.3.5 Problems Encountered -Changes Made
4.4 Turbine/Generator
5.0 INSTRUMENTATION
5. 1 Main Dam Area
5.1.1 Main Dam and Spillway Settlement
5.1 .2 Main Dam and Spillway Seepage
5.2 Power Tunnel
5.3 Seismic Monitoring
5.4 Stream Flow Monitoring
6.0 REFERENCES
iii
4-4
4-5
4-7
4-9
4-11
4-16
5-4
5-4
5-5
5-5
5-6
5-6
TABLES
No. Ti I Page No.
3-1 Dam Design Factors of Safety 3-11
3-2 Dam Static Stability Summary 3-12
3-3 Dam SARMA Analyses Summary 3-13
3-4 Spillway Design Factors of Safety 3-17
3-5 Spillway Pseudostatic Analyses Summary 3-18
3-6 Spillway Finite Element Analyses Summary 3-18
3-7 Spillway SARMA Analyses Summary 3-19
3-8 Powerhouse Design Factors of Safety 3-20
4-1 Bradley Lake Filling Elevation Levels 4-18
4-2 Monument Settlement Data-Dam Upstream Face 4-19
4-3 Monument Settlement Data -Dam Crest and Spillway Crest . 4-20
4-4 Monument Settlement Data -Dam Downstream Bench 4-22
4-5 Monument Offset Data-Dam Upstream Face 4-23
4-6 Monument Offset Data -Dam Crest and Spillway Crest 4-24
4-7 Monument Offset Data -Dam Downstream Bench 4-26
4-8 Spillway Seepage Flow Data 4-27
4-9 Power Tunnel Falling Water Test 4-28
5-1 a Frequency of Measurement Inspection After Power Tunnel
Dewatering and During Normal Operation 5-2
5-1 b Frequency of Measurements/Inspection During Filling and
Normal Operation of Reservoir 5-3
5-2 Tunnel Alignment Piezometer Data 5-7
IV
FIGURES
'
No. Tile
1-1 General Plan
2-1 Regional Geology Map
2-2 Power Tunnel Alignment and Major Faults
2-3 Surficial Deposits Map
2-4 Lithologic Composition of Rock Units
3-1 MCE Response Spectra -Mean and Chosen
3-2 Probability of Tsunami Hazard to Bradley Lake Project Facilities
3-3 Generalized Tsunami Wave Force Diagram
3-4 Powerhouse Cross Section Detailing Estimated Tsunami Wave Height
3-5 Bradley Lake Showing the Location of the Potential Slide Area
3-6 Schematic of SSARR Model, Bradley River
3-7 Basin Characteristics for SSARR Model
3-8 Project Design Flood
3-9 Concrete Faced Rockfill Dam, Sections and Details
3-10 Spillway Plan, Elevations and Sections
3-11 Case I -Normal Reservoir, Spillway Stability Analysis
3-12 Case ·II -PMF Reservoir, Spillway Stability Analysis
3-13 Case Ill -Earthquake, Extreme Conditin, Spillway Stability Analysis
3-14 Case IV -Construction, Spillway Stability Analysis
3-15 Intake Channel and Power Tunnel Gate Shaft, Sections and Details
3-16 Power Conduit Plan, Profile and Details
3-17 1 20 MW Pelton Powerhouse
3-18 Powerhouse Substation and Bradley Junction
3-19 Diversion Tunnel, Sections and Details
4-1 . Monument· Settlement Data -Dam Upstream Face
4-2 Monument Settlement Data -Dam Crest
4-3 Monument Settlement Data -Spillway Crest
4-4 Monument Settlement Data -Dam Downstream Bench
( 4-5 Monument Offset Data -Dam Upstream Face
v
4-6 Monument Offset Data -Dam Crest
4-7 Monument Offset Data -Spillway Crest
4-8 Monument Offset Data -Dam Downstream Bench
4-9 Spillway Seepage Flow Data
4-10 Turbine Efficiency Test Results
5-1 Main Dam Area Survey Monumentation
5-2 Spillway Weir Diagram
vi
PROJECT DESCRIPTION
1.0 PROJECT DESCRIPTION
The Bradley Lake Hydroelectric Project is located on the Kenai Peninsula, about 1 05 miles
· southwest of Anchorage, and 27 miles northeast of Homer, Alaska. Figure 1-1, General Plan,
is a Project Map showing the Project facilities.
1.1 SITE CLIMATOLOGICAL DATA
The Kenai Peninsula is strongly influenced by the maritime climate that prevails along coastal
regions adjacent to the Gulf of Alaska. Cool summers and moderate winter temperatures
prevail, with occasional winter intrusions of cold Arctic air masses. Fog, rain, and clouds
occur frequently and gusty, turbulent winds are common. Precipitation is light during late
winter and early spring, and typically increases to maximum amounts from August through
December, varying with geographic location and elevation. Precipitation in the lower
elevations is predominantly rain with upper elevations receiving snow.
The Kenai Peninsula at lower elevations is generally forested with stands of mixed deciduous
. and coniferous species. Typically, Sitka spruce and paper birch dominate upland habitats; low
shrubs occupy poorly drained bogs and meadows; and cottonwood, alder, and willow
dominate floodplain habitats. At upper elevations dense forests give way to sub-alpine
communities typically composed of a wide variety of shrubs and herbaceous species.
Bradley Lake is located in the Kenai Mountains about five air miles east of Kachemak Bay at
an elevation of approximately 1 ,080 feet. The surrounding area consists of steep-sloped
mountains reaching 6,000 feet in height, and is dominated by the lake and canyon of Bradley
River. The lake is about three miles long and varies from approximately 0.2 miles to 1.2 miles
in width.
Kachemak Bay is subject to tidal fluctuations of up to 27 feet (Figure 1-1 ). Although some
ice may form during cold winters, the major portion. of the bay is essentially open all year.
1-1
~-
(
\
Ice and heavy snow may be accumulated in varying snowfall typically in December and
January. Depths of snow at the project site may range from 60 inches at lower elevations
to greater that 1 00 inches at higher elevations.
Winds vary due to changes in coastal and mountainous terrain. Wind speeds have been
clocked at speeds as high as 95 mph in some of the mountain areas, with gusts at greater
speeds.
1.2 DESIGN AND CONSTRUCTION OF PROJECT
Stone & Webster Engineering Corporation CSWEC) performed the feasibility study and
licensing work and prepared·the final design of the project. Bechtel Corporation (Bechtel)
.provided construction management for the project. The Bradley Lake Project was constructed
in phases under the following major contracts.
• Site Preparation Contract
• Turbine Generator Procurement Contract
• General Civil Construction Contract
· • Powerhouse Construction Contract
• Transmission Line Construction Contract
• SCADA Procurement Contract
• Middle Fork and Nuka Diversions Construction Contract
• Site Rehabilitation Contract
Site Preparation Contract
Project development accomplished under the Site Preparation Contract by Enserch Alaska
Construction, includes the construction of a barge dock, access roads, temporary construction
camp, permanent housing facilities, a temporary landing strip, excavation of the Main Dam
Diversion Tunnel and construction of its intake structure, and the construction of other
structures and facilities incidental to the site development.
1-2
Turbine Generator Procurement Contract
This procurement Contract purchased the major operating equipment for the powerhouse.
The Turbine Generator procurement Contract was awarded to NISSHO IWAI American
Corporation/Fuji Electric Company, Ltd.
General Civil Construction Contract
This Contract was awarded to Enserch Constructors J.V. in June 1988 and included
construction of the· power tunnel, main dam and spillway, powerhouse excavation and
completion of the diversion tunnel.
Powerhouse Construction Contract
This Contract was awarded in December 1988 to H.C. Price Construction and consisted of
the erection of the equipment supplied by the Turbine Generator Contract and construction
of the powerhouse that houses the generating equipment and the 11 5 kV substation located
at the powerhouse.
Transmission Line Construction Contract
This Contract was awarded to Newbery Alaska, Inc. in June 1989 and included construction
of two parallel 19 mile 11 5 kV transmission lines and a switching station to connect Project
Generation with the Railbelt Utility Electric System.
SCADA Procurement Contract
This Contract was awarded to Landis and Gyr Powers, Inc. in July 1989. This supplier
furnished equipment for remote control and monitoring of Project features.
1-3
Middle Fork and Nuka Diversions Construction Contract
This Contract was awarded to Wilder Construction, Inc. in 1990 and included construction
of two diversions in the Bradley River watershed.
Site Rehabilitation Contract
This Contract was awarded to Doyle Construction Company in June 1991 and included
restoration of the construction camp site, construction of a permanent, above ground fueling
station, construction of a waterfowl nesting area and fish rearing ponds, removal of a
temporary construction road and installation of an overland power cable from the powerhouse
to the power tunnel gatehouse.
1-4
I BRADLEY JUNCTION
I I'-HOMER ELECTRIC ASSOCIATION
I F RITZ CREEK-SOLDOTNA 1111 KV
TRANSMISSION LINE
I
I ~c:" --::··· = •• ._ .. ._ o ...... "" ... ,.... ,, .. , -.... , .... .. .. -n .eo '·'' ... , -..... . .... . ... . ... CA~.!:::. -.... .... _ ....
.... . .•. . .... . .... ...... .... -···· •t & ..
......
TRANSMISSION
LINE ROUTE.
,-----:_: (
I
,
FIGURE 1-1
GEOLOGIC SETTING
2.0 GEOLOGIC SETTING
2.1 REGIONAL GEOLOGY AND TECTONIC CONDITIONS
The portion of the Kenai Mountains in which the Bradley Lake project area is located is
composed of upper Mesozoic Age metamorphic rocks of the McHugh Complex. A map of the
regional geology is presented in Figure 2-1. Contrasting depositional environments, mode of
deformation and general lack of continuity of units indicate that the McHugh Complex,
including the Bradley Lake area, represents a melange deposit in which rocks have been
tectonically mixed, uplifted, deformed, and accreted onto the North American Plate.
The primary large-scale expression of the tectonic influence on the project area is the Aleutian
Arc-Trench, which lies 185 miles southeast of Bradley Lake, and parallels the prevalent
northeast-southwest strike of the prominent tectonic features found in and around the project
area.
The Aleutian Trench is a result of the northward movement and underthrusting of the Pacific
Plate beneath the North American Plate, at an estimated rate of about 2.4 inches per year.
The resultant subduction zone, called the Aleutian Megathrust, dips to the northwest and
corresponds to a zone of seismic activity called the Benioff zone. This zone marks the
boundary between the two colliding lithospheric plates, is an indicator of substantial regional
tectonic activity, and has been the focus of several major historic earthquakes in southern
Alaska. At the project area, the Benioff zone lies abqut 30 miles beneath the earth's surface.
The Border Ranges Fault marks the northern margin and suture line of the McHugh Complex,
while the Eagle River Thrust Fault and adjacent Valdez Group rocks mark the southern limit
of the complex. In the Bradley Lake area, the Border Ranges Fault lies under Kachemak Bay,
and the Eagle river Fault crosses Bradley Lake near its head. Both faults trend northeast-
southwest. Within the project area, the locally prominent Bradley River, Bull Moose, and Bear
Cubs Faults, as well as a complex network of secondary faults, fracture zones, and major joint
sets are expressed by lineaments that generally parallel the same regional structural grain.
2-1
The Bradley River Fault and the Bull Moose Fault cross the power tunnel alignment about
4,200 ft and 11,600 ft, respectively, from the intake area at Bradley Lake (Figure 2-2).
The tremendous forces operating on the area during accretion created large tectonic features,
and also imparted the melange and cataclastic structures on the rock, as manifested by the
intimate shearing and flow mixing of graywacke, argillite, metatuff and chert. This occurs at
all scales ranging from teRths of an inch to hundreds ·Of feet.
The compressional stresses inferred to have been responsible for the structure found at the
Bradley Lake area do not appear to be active at this time. Although the overall stress regime
· for the Southcentral Alaska Area is compressional on a generally northwest-southeast axis,
the current configuration of plate boundaries and the location and orientation of the
subduction zone suggest that the regional stress regime of the Kenai Peninsula is, at least
temporarily, in a low stress situation. A hydrofracturing test conducted along the pressure
tunnel alignment also indicated that horizontal stresses are l~ss than the vertical stresses.
A detailed description of the regional and site geology is given in the "Geotechnical
Interpretive Report" prepared by SWEC.
2.2 OVERBURDEN
Unlithified deposits in the project area consist of glacial till and outwash, colluvium, alluvial
channel, flood plain and deltaic deposits, peat and marine intertidal deposits (Figure 2-3).
Locally these deposits and bedrock may be overlain by an organic mat generally not more than
three feet thick, consisting of moderately to poorly drained silty loam soils with 1/2 in. to 1
in. layers of volcanic ash, and moderate to high organic content.
Peat deposits 1 - 1 0 ft thick are found in topographic depressions and poorly drained areas
that are generally saturated and characterized by lack of deciduous vegetation. They typically
surround small ponds and locally, may be separated from bedrock by a thin layer of gravel till.
2-2
Alluvial gravels and cobbles in a matrix of silt and sand occur as stream channel, flood plain
deposits 5-40 ft thick. Gravel to boulder size talus with occasional very large blocks, derived
primarily from argillite and graywacke, occurs within colluvial deposits. These deposits lie
below steep slopes and rock exposures, such as in the damsite and Bradley River gorge areas.
Deltaic deposits such as those at Battle Creek and Martin River are believed to average at
least 40 ft thick. The Martin River borrow area is located within an alluvial fan-delta complex.
The fan is composed of braided river deposits superimposed on deltaic sediments. Sediments
in the Martin River Delta vary from gravel with sand and cobbles to sand with gravel and
occasional silt layers. The upper (near surface) portion of the delta generally consists of larger
gravel with less sand than in the deeper portion of the delta.
Colluvial deposits consisting of sand to boulder size clasts in a silt matrix are generally 5 to
1 5 ft thick. Colluvium may overlie any of the other unlithified deposits and is commonly
found along and below slopes.
Glacial tills composed of poorly sorted silt, sand, gravel and cobbles are found along the shore
of Kachemak Bay from Sheep Point to the Bradley River. The thickness of these deposits vary
from zero to greater than 40 feet.
2.3 BEDROCK MATERIALS
The basic rock types identified in the project area are graywacke, argillite, chert, dacite,
metatuff, and greenstone (Figure 2a4). A detailed lithologic description of each rock type
follows. It should be noted that overall rock character correlates to the proportions in which
the constituent lithologies are present.
·2.3.1 Graywacke
Graywacke is defined as a dark gray, coarse-grained sandstone containing poorly sorted
angular to subangular grains of quartz, feldspar, dark minerals and lithic fragments in a silt and
clay matrix.
2-3
The rock is generally massive and homogeneous, and displays no visible bedding. It is very
poorly foliated to unfoliated, but may be locally strongly jointed, with weathered and stained
joint surfaces extending up to 1 00 ft below ground surface. Discontinuous veinlets of quartz
and calcite, generally less than 0.4 in. wide and 2-12 in. long, are common.
As the grain size and sand fraction of the graywacke decreases, the graywacke characteristics
grade toward those of argillite. In addition; soft-sediment compositional mixing between
components of argillite and graywacke parent material creates a gradational series that
combines the properties of the two end members.
2.3.2 Argillite
Argillite is derived from mudrock, lacks fissility, is more highly indurated than shale. or
mudstone, but is not metamorphosed to the degree of slate and does not have the cleavage
of slate.
Within the Bradley Lake area, the argillite is a charcoal-gray to black rock composed of silt and
..
clay-size grains with very few or no sand grains. The argillite is generally fresh to moderately
fresh and moderately hard. Moderately weathered material may be soft. Bedding is rarely
seen, and where visible, is poorly preserved. White quartz and calcite veinlets up to about
0.8 in. in thickness are common. Most weathering develops along fracture and foliation
planes which may penetrate deep into the rock mass. The effects of weathering generally. do
not extend more than 0.05 in. from the plane.
2.3.3 Chert
Chert is both a mineral name used to describe the microcrystalline form of quartz, and a rock
term to describe nodular concretions and massive layers of cryptocrystalline or
microcrystalline quartz. Chert is extremely hard and compact and may form as an original
precipitate or as a replacement product.
In the Bradley Lake Project area, chert appears to occur most commonly as light to dark gray
·nodules, lenses and massive layers in the argillite and metatuff. The nodules are rounded and
2-4
commonly have diameters ranging up to 6 in., although a few 40-in. thick nodules were
noted. The nodules are elongated parallel to the foliation in the argillite, which is deformed
in curves around the chert nodules.
2.3.4 Dacite
Dacite is a fine grained igneous rock with a mineralogic composition equivalent to quartz
diorite. In the Bradley Lake area a number of small dikes (apparent thicknesses of 5 ft to 50
ft) have been encountered. In the project area the name is applied to a light gray-green, very-
fine to coarse-grained, intrusive igneous rock composed primarily of plagioclase and quartz.
The dacite is very hard to extremely hard and generally fresh. No foliation is visible and joints
are generally well developed. Several dacite dikes are structurally deformed (faulted and
folded) but are generally continuous over a considerable length, and none display evidence of
having undergone as extensive a deformational history as the surrounding country rock. The
widths of the dikes range from 1 to 40 feet, generally not exceeding 1 0 to 20 feet .in width.
2.3.5 Metatuff
Metatuff, a rock composed of metamorphosed pyroclastic volcanic debris, is common
throughout the McHugh Complex. In the Bradley Lake area two varieties of metatuff were
mapped, but these comprise less than 5% of the total rock encountered in the project area
investigations. Type I is megascopically described as pale green in color with a dull, earthy
luster, and is intimately associated with argillite (mixed in approximately 0.05 in. to 1 in.
discontinuous layers). Engineering properties are similar to argillite, and foliation is generally
well developed. This variety represents a distinct but minor portion of the mapped metatuff.
The metatuff Type II variety is green to light gray in color, appears more massive in the field
(occurring in 1 to 15 ft thick layers), and is also associated with argillite. Engineering
properties of the Type II metatuff are similar to those of graywacke, in that it is generally hard
to very hard, strongly jointed, and poorly foliated. Chert nodules and lenses up to several feet
·thick are commonly associated with the metatuff.
2-5
2.3.6 Greenstone
Greenstone is a field term generally applied to a dark green, metamorphosed, basic igneous
rock that owes its color to the presence of chlorite, epidote, or actinolite. The units mapped
as greenstone comprise less than 3% of the total rock encountered in project area
investigations. The greenstone is dark green, very hard, massive, has a high specific gravity,
and exhibits slightly iridescent weathering surfaces with a reddish tinge.
The greenstone occasionally displays a pillow basalt type structure and it strongly jointed but
not foliated. The greenstone is interpreted to have been subject to cataclasis but does not
exhibit the extensive deformational effects of the other rock units in the project area. In
addition, the greenstone does not occur intermixed with argillite, graywacke, or chert and
appears to have an origin distinct from that of the other rocks in the project area.
2-6
-+-
-t--
g QUATERNARY ~
N ~ ~ TERllM'Y n.
t?(Ll
CRETAC£0..6
JURASSIC ~ a.fr~rus ....
~ ""RASSIC I 0 ~ ... IASSW: " '
.
u T•m
0 PALEOZOIC B88ll!l 2 AND OR ...... .. NESOZOIC :
~!!!!!!liiiii;iiii~lii!O!!!!!!!!~I5Diiiiiiii~2~0!!!!!!!!2ll! WILES
LEGEND
ANTIO,.INE-GE!ERALIZED ON IIJ:IFlCIAL DEPOSIT! AHO P11 THE OFFSHORE
SPICUlE· GDIERALIZED OH SI.JiFICtAL DEPOSITS
IMD IN THE OFFSHORE
~FALtf.Dlo~o=-~o:er.~lo u,
THitUST OA REVEftSE P'AUU'-DarTED WHERE
COIIC£ALED, s.tWTEETH ON UPTHROWN Bl..OCIC
COMTOCT
OUM'rERNAAY DEPOSffS
JCEHAI GAOt.Po SANDSTONE, SILTSTONE AHD SOM[
COAL
GRANITE, QUARTZ MONZONITE AND SYENITE
t~.L~"r~r:~tt.1r~
MCHUGH COIIIPLIXJ Wl£.tJCIY UElaNORPHOSED ~~=l~~=~;~s~E~~«M .
LAVA FLOWS
L..niUnJH£ AND FIN£ GRAUII!D TUFF
COiffOATED t.ND SOME GREEN!ITDNE
I&.U'IC ROCKS • PIUOW USAlJ' AND SOU! CHERT
UIIMO AND UURAMAFIC ROCKS
REGIONAL GEOLOGY MAP
. FIGURE 2-1
D FROM Flo. 19 ADA PTE
or-OIR-tSWECJ .
\.···
Oo
ooi)
(.
\\~CAM' CCESS ·~
r r.
Oo 8
0 ~oo 2 '00 000 :r-
FIGURE 2-3
ROCK COMPOSITION WITHIN
THIS AREA WAS NOT
ENCOUNTERED
CHERT
100%
GRAYWACKE
100%
100%
METATUFF
FIGURE 2-4.
ARGILLITE
100%
LITHOLOGIC COMPOSITION OF ROCK UNITS
SUMMARY OF DESIGN
c
3.0 SUMMARY OF DESIGN
3 .. 1 GENERAL DESIGN PARAMETERS
3.1.1 Earthquake <Seismic) Design Criteria
Great earthquakes (Richter magnitude M, = 8 or greater) and large earthquakes (M, = 7 or
greater) have occurred historically throughout the region and can be expected to occur in the
future. Historically (1899 to date),.eight earthquakes ranging between M,= 7.4 and Ms= 8.5
have occurred within 500 miles of the site. It is therefore concluded that the site will
probably experience at least one moderate to large earthquake during the life of the proposed
project. The ,possibility of significant ground rupture exists but is much less subject to
prediction and is considered to have a much lower probability.
The response spectra utilized for the stability analyses were taken from a report prepared by
Woodward-Clyde Consultants (WCC) for the Corps of Engineers. The report documents the
work performed by WCC to develop parameters for what the Corps terms the "design
maximum earthquake" and the "operational base earthquake" (henceforth called Maximum
Credible Earthquake and Design Basis Earthquake, respectively). The Maximum Credible
Earthquake (MCE) is defined as the most severe earthquake believed to be probable which
could affect the site. The Design Basis Earthquake (DBE) is less severe, and is defined as the
seismic level which is considered as likely to occur during the life of the project. Maximum
Credible Earthquakes are normally used as a basis for determining whether or not certain
structures can withstand extreme events having remote probabilities of occurring, regardless
of damage level. Design Basis Earthquakes are used as a basis for estimating the maintenance
and other costs resulting from events expected to occur, and for design of non-critical
structures where severe damage and loss of function in a major seismic event are considered
an acceptable risk.
Based on their work on the seismicity of the site, WCC proposed two possible response
spectra for the "design maximum earthquake", the equivalent of the MCE The one which
was expected to control was based on rupture of one of the faults nearest the site. The
3-1
(
/
resulting earthquake would have a magnitude of M. = 7 .5, peak ground acceleration of 0. 75g
at the site, and a significant ground.motion duration of 25 seconds.
The other possible MCE was a Megathrust event tied to the Benioff Zone roughly 30 miles
beneath the site. This event would have a magnitude of M.=8.5, peak ground acceleration
of 0.55g at the site, and a significant ground motion duration of 45 seconds. It was not
expected to be the controlling event unless the faults in the immediate vicinity of the site
could be shown to be inactive.
A third response spectrum proposed by WCC was an event with a peak ground acceleration
approximately one half that of the MCE (0.35g) for use as the DBE.
Since all critical structures of the Bradley Lake Project are founded on bedrock, accelerograms
recorded on rock from large magnitude earthquakes having similar peak parameters to those
.listed above for the crustal event would ideally be used for the required analyses. At the time
the analysis was being performed, no accelerograms recorded on rock in the near field of large
magnitude earthquakes (M 5 = 7 .5) were available from anywhere in the world, including
Alaska. Consequently, available accelerograms from historical earthquakes having appropriate
peak and spectral characteristics over a broad period range, even when scaled, were not
available for use.
Since no actual accelerogram was available, a compositehybrid accelerogramwas derived. for
the dam stability analysis from. the historical accelerograms of two earthquakes having
appropriate characteristics. This approach has been previously used for other studies,
including those performed by the California Department of Water Resources for Oroville Dam,
and is considered an appropriate state-of-the-art method for simulation of strong motion
events.
After examining the response spectra for recorded accelerograms from a number of
' earthquakes in )the United States and abroad, it was concluded that a suitable accelerogram
for the Ms = 7.5 crustal event could be obtained. The resulting accelerogram, called the Hybrid
record, is shown on Figure 3-1. The significant duration of the Hybrid record is 28.8 seconds,
which is slightly longer than the 25 second MCE proposed by WCC. This longer event
3-2 r
--r'
'
duration, when combined with the greater density of high acceleration peaks from the
combined records, results in a design record which is conservatively intense and definitely on
the "safe" side when used to simulate the project -MCE.
3.1.2 Tsunami Hazard Evaluation
Project facilities including the powerhouse and barge dock may experience a large tsunami
associated with earthquake or volcanic.activity. The probability of such an event occurring
sometime during the 50-year design life of the project is low.
The wave height of a tsunami, with an annual probability of occurrence of 0.007, is
approximately El. 25, BLHP Datum (Figure 3-2). This design case resl,llted in a total dynamic
force of 192 kips/ft that was applied in the structure stability analyses of the west wall-of the
powerhouse (Figures 3-3 and 3-4).
3.1.3 Reservoir Seiche Hazard Evaluation
By examination of the Bradley Lake reservoir rim and shoreline most likely to experience a
landslide during a major earthquake, investigating the subsurface geology, and using both
analytical and comparative techniques; an estimate was made of the volume of material in the
Kachemak Creek Delta at the head of the lake which might liquefy during an earthquake,
causing a subaqueous landslide, and thereby inducing a wave in the Bradley Lake reservoir.
The estimated volume so obtained was 4,000,000 cubic yards. The mass mobilized during
this postulated subaqueous landslide would be a 200 foot wide band along two-thirds of the
5500 foot width of Kachemak Creek Delta at the head of the lake (Figure 3-5). The MCE
event was used to generate the landslide.
The magnitude of the wave which would be generated by this landslide and the propagation
of the wave approximately three miles along the lake to the dam were calculated. The use
of three wave propagation methods yielded similar results, the largest of which indicated a
9.7 foot wave height at the dam. The analysis was conservatively performed with the lake
water surface at elevation 1180, the maximum normal operating level. No reduction in wave
3-3
magnitude was made for the attenuating effect that the southwest portion of the lake
shoreline, which juts out in front of the dam blocking the path of the wave, would have.
The analysis showed that the dam parapet would not be overtopped and that the wave force
would be less than that for .which the top of the rock fill dam is designed.
3.1.4 Project Hydrology
Probable maximum Flood (PMF) for the Bradley Lake basin and for the Middle Fork Diversion
basin were computed by the Alaska District, Corps of Engineers during its feasibility
investigations of the project in 1979-1982. The following summarizes the methodology,
criteria, and results of those studies as presented in its reports entitled "Design Memorandum
No. 1, Hydrology" dated June, 1981, and "Design Memorandum No. 2, General Design
Memorandum," dated .February, 1982.
The methodology, criteria, and results of the Corps of Engineers flood studies were review by
Stone & Webster and found to be reasonable and acceptable. Also, the low level outlet or
powerhouse hydraulic capacities were not utilized· in reducing the ·PMF discharge, and this
approach was retained when designing the Project spillway structure.
3.1.4.1 Study Methodology
A mathematical model of the Bradley Lake basin was developed to compute the PMF
hydrograph. The watershed model was established using the Streamflow Syntheses and
Reservoir Regulation (SSARR) computer program developed by the North Pacific Division,
Corps of Engineers.
In order to verify the simulation of the physical and hydrologic characteristics of the basin,
several historical flo.ods were reconstituted using the SSARR program. In addition, to better
establish glacial runoff parameters, the model was calibrated against runoff from Wolverine
Glacier, located 25 miles northeast of Seward.. Daily streamflow, temperature, and
precipitation were available at Wolverine Glacier and greatly improved the reconstitution.
3-4
Schematic diagrams of the basin models used for reconstitution of flows for Bradley River and
Wolverine Creek are shown on Figure 3.6.
The Hydrometeorological Branch, National. Weather Service (NWS), developed . probable
maximum storm criteria of the Bradley Lake basin in their report entitled "Study of Probable
Maximum Precipitation for Bradley Lake Basin, Alaska," dated May, 1961. Estimates from
this report ~ere reviewed by the NWS in June, 1979 and found to be still valid.
3.1.4.2 Precipitation and Infiltration Loss
The basins were divided into subbasins as depicted in Figure 3.6. These subbasins represent
the glacial and nonglacial regions of the basin, with the glacial ar:eas further subdivided into
elevation zones in which temperature dependent processes can be simulated. Separate basin
characteristics were derived of the glacial and nonglacial areas, and are illustrated on Figure
3. 7. Snowmelt and precipitation on each of the subbasins were input to the model and losses
simulated to obtain the increments of excess water which were converted to surface,
subsurface, and base flow. Total runoff is dependent on the Soil Moisture Index (SMI).
Data from Homer and Seward were used as indices to precipitation. Since these stations
showed variation in daily precipitation in the basin, station weights were adjusted on a storm-
by-storm basis to simulate storm runoff volumes. Reconstitutions were therefore made for
individual rainstorms.
Data from Homer, adjusted for a lapse rate of 2.9 D F/1 ,000 feet, were used as an index to
basin temperature. Melt rates were based on average daily temperatures.
Since all reconstitutions were for rainfall events occurring in late summer, it was assumed that
all nonglacial areas were snow-free. The snow covered area in each glacial elevation bank
was set at 1 00 percent, with the snow water equivalent arbitrarily set at 300 inches for each
bank to simulate the effect of the glacier. The temperature index method was used for
computing snowmelt utilizing a constant melt rate of 0.098 inchesr F-day.
3-5
Losses were simulated for each time period in the program by the Soil Moisture Index CSMI).
( : Runoff is a function of the SMI, which varies for each time period and which is derived from
_/
the SMI for the previous period, runoff generated in the previous period, and the
evapotranspiration index. B.oth glacial and nonglacial areas assumed high runoff percentage.
The separation of total runoff into the components of flow is variable in the computer
program. On the nonglacial areas, the portion of water input contributing to base flow
decreases as the Base Flow Infiltration Index (BII) increases. On glacial areas, there were
initial minor decreases in percentage of runoff converted to base flow, but base flows were
then held constant at 95 percent of total runoff, as it was assumed that most melt and rainfall
" runoff would flow into crevasses and emerge as subglacial flow. Although termed base flow,
routing phases and periods were set such that glacial "base flow" still exhibited rapid runoff
characteristics.
Because the basin lacks any extensive soil cover, the surface-subsurface split for nonglaical
areas assumed that most runoff occurs as surface flow. The base, subsurface, and surface
flow for each subbasin were routed and combined to yield the total subbasin outflow.
Subbasin ·OUtflows were combined with other subbasin flows to produce the total runoff
hydrograph.
3.1.4.3 Watershed Model Calibration
The SSARR watershed models for both the Bradley Lake basin and the Wolverine Glacier basin
were verified by comparing the computed and observed discharge hydrographs at stream
gauging stations on Bradley River near Homer and on Wolverine Creek near Lawing. The
following events were selected for flood reconstitution studies:
• August-September 1974 (Wolverine Creek)
• 1 0-20 August 1958 (Bradley River)
• 8-17 September 1961 (Bradley River)
• 10-30 September 1966 (Bradley River)
) The Bradley Lake basin, because of. its· elevation, proximity to the Gulf of Alaska, and
exposure to storms moving into the Gulf of Alaska, receives precipitation amounts exceeding
those recorded at the coastal weather stations. Because of the difficulties o.f verifying
computed hydrographs in early summer and in assigning proper precipitation weights over an
extended period of time, individual storms were reconstituted for the August-September
period (when rainfall is greatest), adjusting precipitation weights until computed runoff
volumes matched observed runoff volumes.
The reconstitutions follow the .general timing and pattern sufficiently well to justify application
of the method to PMF derivation. Confidence can be placed in the glacial runoff
characteristics as derived from the reconstitution for Wolverine Creek, where adequate data
were available. Runoff characteristics for the nonglaical areas of Bradley Lake were estimated
from hydrological reconnaissance studies, and are believed to be fairly reliable due to the
impervious character of the basin.
3.1.4.4 Probable Maximum Precipitation
The Hydrometeorlogical Branch, National Weather Service, determined that the Probable
Maximum Precipitation (PMP) would be a combination of the orographic and nonorographic
rainfall occurring in either-August or September. The rainfall was distributed in 6-hour periods
in the manner prescribed by the NWS. The total 72-hour precipitation for the PMF is 41.0
inches with a maximum 6-hour accumulation of 11 . 1 inches. As the NWS indicated the air
temperatures during the August PMP are expected to be about 2 • F higher than those during
the September ~MP, the PMP is forecast for August.
A 3-day antecedent rainstorm was assumed to occur before the PMP storm, using 1 00-year
rainfall data taken from U.S. Department of Commerce, Technical Paper No. 47 and Technical
Paper No. 52. The antecedent rainstorm was logged in 12-h.our intervals .to determine the
sensitivity of the PMF to the timing of the antecedent storm. Since the PMF is relatively
insensitive to the length of time between storms, a 48-hour lag time between storms was
taken as a reasonable time period, and used in the derivation of the PMF.
3-7
Snowmelt was handled in the same manner as in the flood reconstitutions. The temperature
index method was used to compute melt from the glaciers. It was assumed. that nonglacial
areas were .snow-free. The snow water equivalent for each glacial elevation band was
arbitrarily set at 300 inches. A constant melt rate of 0.098 inchesr F -day was used.
The NWS report includes the temperatures to be used during the probable maximum storm,
and gives a temperature envelope to be used for the periods before and after the storm. The
highest temperatures in the envelope were utilized to maximize snowmelt.
3.1.4.5 Probable Maximum Flood
The streamflow records for the Bradley River at the lake outlet indicate that the maximum
annual peak discharge normally occurs between August 1 and October 31 from a summer
rainfall flood. The National Weather Service estimated that the probable maximum storm
would occur in either August or September. The probable maximum flood was developed
utilizing storm criteria for August developed by the Hydrometeorological Branch, National
Weather Service, with the 1 00-year storm assumed as an antecedent rainstorm.
The SSARR model developed from flood reconstitutions was used for the PMF determination
for Bradley River. The SSARR model for PMF determination of the Middle Fork Diversion was
developed using basin characteristics derived for the Bradley Lake basin.
Separation of flow and losses during PMF runoff were simulated in the same manner as in the
fl.ood reconstitutions.
The Corps of Engineers PMF inflow hydrograph including Nuka runoff and Middle Fork
Diversion flows, developed as described above, was adjusted upward to 800 cfs to include
400. cfs additional inflow from Middle Fork Diversion.
3.1.4.6 Spillway Design Flood
The Spillway Design Flood (SDF) for the Bradley Lake basin is the spillway discharge when
the PMF is routed through the re.servoir. The most critical period occurs during late summer
3-8
when the reservoir is at maximum level and the probability o~ receiving the PMP is greatest.
The starting water surface is at spillway crest Elevation 1180.0. The spillway is an
uncontrolled ogee type with a crest length developed to handle the PMF inflow while
maintaining a maximum reservoir elevation of 1 190.6 when the PMF was routed through the
reservoir.
The PMF inflow and routed outflow hydrographs and a plot of the corresponding Bradley Lake
water surface elevations are shown in Figure 3.8. The peak inflow is 31,700 cfs ·and includes
flows from the Middle Fork Diversion of up to 800 cfs and Nuka glacial flows. Also, it was
conservatively assumed that no water is diverted into power generation during this routing.
The maximum spillway outflow (the Spillway Design Flood) is 23,800 cfs. The channel
downstream of the spillway and the riprap protection on the downstream face of the dam
were sized to handle this flow.
3._1 .4. 7 Physical Model Test
Part of the 1:50 scale hydraulic model constructed by the Colorado State University
Engineering Research Center In Fort Collins, Colorado, included the spillway and downstream
pool and channel.
The model test results showed excellent correspondence between the theoretical spillway
discharge rating curve and that which was measured. For the lake at the PMF elevation, the
model test indicated a flow of 23,860 cfs. This is only 60 cfs different from the calculated
flow. The observed flow conditions for the spillway at all reservoir elevations were
satisfactory. One small eddy shedding zone at the left abutment (seen at high flows) was
corrected by developing a more streamlined geometry.
The model also showed that the downstream channel was capable of conveying the PMF.
The measured velocity and water surface elevations at the downstream face of the dam
during PMF testing was used in designing the riprap protection which will be placed there.
3-9
3.2 · MAIN DAM
3.2.1 General Description
The main dam is a concrete-faced rock fill structure with a crest length of 600 feet at an
elevation of 1190. It has a maximum height of 125 feet (Figure 3-9). The crest acts as a
roadway to the diversion tunnel gatehouse and spillway. A 4 foot high parapet wall on the
upstream side of the crest prevents overtopping of the dam by waves during the probable
maximum flood. The upstream concrete face and the downstream slope of the rockfill
embankment have side slopes of 1.6H:1V. The concrete face is joined to a concrete toe
plinth founded on sound rock. A single line grout curtain to depths of 11 0 feet along the
length of the toe. plinth provides a foundation seepage barrier.
3.2.2 Stability Analyses. Assumptions and Results
The Bradley Lake dam was analyzed to determine its factor of safety under various static
loading conditions, and to predict its potential deformation under seismic loading conditions.
The basic requirement which must be met by the embankment design is that the reservoir·
must be retained under all conditions evaluated. Dam safety criteria were established for this
analysis to aid in evaluating embankment performance.
For static loading conditions, factors of safety were calculated and compared with design
criteria minimum ·safety factors. These minimum safety factors were based on current
industry standard practice. The calculated factors of safety were greater than or equal to the
recommended minimums.
For dynamic loading conditions, the safety criteria were in the form of deformation limits since
a safety factor is often not relevant to fill structures under dynamic loading. The limit of
vertical and horizontal deformation was based on the need to keep the bedding layer beneath
the concrete face sufficiently intact to limit seepage through the embankment after a major
earthquake. A calculated allowable limit of 2 to 3 feet of vertical displacement was adopted.
3-10
~r· Displacement variations could be very large if greater calculated values of displacement are
used.
The static stability· analyses were conducted using the LEASE II computer program to
determine the critical potential slip surfaces and their critical accelerations. The analysis was
conducted for both the upstream and downstream slopes. Load cases analyzed are listed
below in Table 3-1.
1.
2.
3.
Table 3-1
DAM DESIGN FACTORS OF SAFETY
Load Case
Normal Pool Level:
Dead + Live +
(Wind or ice)
Dead + Construction
Operational Drawdown
Emergency Drawdown
Main Dam
1.5*
1.2
1.2
1.0
Cofferdam
1.2 *
1.05
N/A
N/A
4. PMF Pool Level:
5.
Dead + Live
Seismic Loss of Freeboard t
(Max Loss/Total Freeboard)
Dead + MCE Earthquake
Dead + DBE Event
Dead + Megathrust Event
1.5
.s. 50%
(MCE)
N/A
N/A
* Factors of safety were calculated by "infinite slope" analysis. Failures of
significance to the integrity of the dam (i.e., penetrating water retention zone) have
higher ~afety factors. U/S analysis neglects support from concrete face slab and
headwa,ter.
t See section 3.1. 1 for definition of earthquake loads.
3-11
1.
2.
'3.
4.
Table 3-2
DAM STATIC STABILITY SUMMARY
Loading Condition
(see Table 3-1)
Definition
a. Normal Maximum Operating H.W. El 1180
T.W. El 1065
,b. Normal Minimum Operating H.W. El 1090
T.W; El 106-5
Safety Factors Criteria
U/S D/S Minimum
1.66 1.78 1.5
1.66 1.78 1.5
End of Construction
Rapid Drawdown
These cases reduce to Normal Minimum operating
case due to features of the upstream -cofferdam
which result in headwater retention at El 1090 even
if lake level drops lower. _{
Design Flood-PMF · H.W. El 1190
T.W. El 1082
·H.W.
T.W.
= 'Reservoir Headwater Level
= Dam Toe Tailwater Level
'1.66 1.78 1.5
\ : The dynamic stability analysis was conducted using the SARMA (Seismic Amplification
Response by Modal Analysis) niethod. The SARMA method _first calculates resonant
frequencies and response shapes-of the embankment dam for each frequency of the
·earthquake. Participation factors-calculated for a given potential failure wedge or block
describe· how much .effect each of the modes of oscillation will have on the potential failure
. .
wedge. The accelerations of the wedge in each mode in response to the earthquake
accelerogram are then calculated, ·and the modes a're combined: . The result is a time-history
of the accelerations the wedge would experience as a result of the chosen earthquake.
Once· the time~history of acceleration -of the individual wedge is known, the cumulative .
. displacement is calculated by Newmark's. sliding l?lock procedure.. In this procedure, the
wedge is assumed to remain fully attached to the rest of the dam as long as the average
acceleration of the wedge is less than a specified critical (or break-free) acceleration. When
the acceleration exceeds the critical acceleration,-the wedge slides relative to the dam until
it comes to rest during a subsequent reversal of the acceler.ation. The total movement of the
wedge is the sum of all the increments of movement that occur during a particular earthquake
record.
3-12
Table 3-3 ·
DAM SARMA ANALYSES SUMMARY
Loading Condition
(see Table 3-1)
J
5. . a. Maximum Credible
Earthquake
b. ·Design Basis Earthquake
c. Megathrust Event
Maximum ·Freeboard Loss (Ft)
UZS Face D/S Face.
2.8 2.4
0.4 0.4
1.4. 1.2
The main dam is considered stable .under all given loading conditions.
3.2.3 Construction
The dam foundation was excavated to sound rock. During the excavation of the dam
foundation a few joints open several inches and filled with dense silt, sand and gravel were
uncovered in the right· abutment. These features were excavated and filled with dental
concrete. Special treatment ·of the-features was completed during foundation grouting.
The grouting program showed the foundation beneath the toe plinth to be extraordinarily tight.
Grout takes in the majority of the holes were negligible and over 90 percent of the holes took
less than five sacks. Explora-to-ry·' core holes completed after grouting confirmed· that the
foundation is tight. Total grout take was 689 sacks for l18 grout holes (7156linear feet).
Foundation conditions in general were good, however, rock quality in the left abutment near
the El 1'200 bench for the power tunnel gateshaft was poorer than expected. Differentially
weathered and fractured rock and open joints were encountered during excavation. For this
reason the left abutment grout curtain was extended 170 feet to the southwest and
terminated at a high rock bluff. Grout takes in the extension were very low with two local
exceptions. Total grout take for the left abutment extension-was 201 sacks for 22 grout
h"oles (1255 linear feet).
3-13
Detailed descriptions of the .dam foundation geology and c:cmstruction of the grout curtain are
found in two r~ports prepared by Bechtel entitled "Final Construction Geology Report" and
"Main Dam and Spillway Grout Curtain Final Construction Report" ..
The dam was constructed of zoned rock fill as designed.· The shell.of the dam is composed
. ' .
of graywacke, excavated from the power tunnel intake excavation, placed in 3-foot lifts and
compacted using a vibratory double drum roller compactor .. The bedding material for the
upstream face slab consists of tunnel boring machine tunnel muck placed in 1-foot lifts and
compacted. The downstream face is armored with a layer of riprap. Construction of the dam
proceeded smoothly with no significant problems or delays. Performance of the dam during
initial filling of 'the reservoir is discussed in Section 4-1, Initial Reservoir Filling.
3.3 SPILLWAY
3.3.1 General Description
The spillway is an ungated concrete. gravity structure with a 175-foot l.ong agee overflow
section at elevation 1180 (Figure 3-1 0). The spillway has an overall. crest length of 275 feet.
A single row grout curtain located near the upstream toe of the spillway provides a foundation
seepage barrier. A line of foundation drainholes located in a drainage gallery near the base
of the structure provides relief of groundwater uplift pressure.
3.3.2 Stability Analyses, Assumptions and Results
The spillway was analyzed to determine stresses and factors of safety under various static
and ·dynamic loading conditions. The spillway was also analyzed to predict maximum
potential movement under seismic loading conditions~ ~tatic loading conditions included
normal maximum reservoir operating level and Probable Maximum Flood (PMF). Dynamic
loading conditions included analysis of the Maximum !=redible Earthquake (MCE) with normal
maximum reservoir level and with a low reservoir level, as well as a pseudostatic analysis of
a lower intensity earthquake during construction. A Design Basis Earthquake (DBE) was also
evaluated to predict maximum· potential movement in order to provide a comparison of MCE
.,\ and DBE results.
3-14
The basic requirement which must be met by the spillway design is that the reservoir must
be retained under all conditions evaluated.
Spillway safety criteria were established to aid in evaluating spillway stability and
performance. These criteria established limiting allowable stresses. and minimum factors of
safety. Each loading condition was classified as either a Usual, Unusual, or Extreme
Condition, and the acceptance criteria were based on currently accepted recommended
minimum factors of safety· for the applicable .loading condition.
The spillway was evaiuated for sliding stability, .for maximum compressive· and tensile
stresses, and for the maximum permanent deformation under dynamic loading. The evaluation
of the sliding stability and stresses was performed in general agreement with the gravity . . .
method as presented in "Design of Gravity Dams", The gravity method was used in both the
pseudostatic and finite element analyses. Perma.nent dynamic deformations were evaluated
using the SARMA method of analysis.
The maximum stresses were evaluated ·for all loading conditions by the pseudostatic method
and for Case Ill (MCE) by both the pseudostatic and finite element methods. For these
analyses,. uplift in an uncracked. section was not included as an active force (i.e., uplift does
not contribute to overturning) since it is an internal pressure resisted by the structure until
cracking occurs. The calculated stress was combined with the uplift pressure · by
superposition to determine the effective stre.ss. For static loading conditions, uplift in a
cracked section was considered as an active force (i.e., uplift in a crack acts as an external
hydrostatic force).
The sliding stability was evaluated for all loading conditions by calculating the shear-friction
factor of safety in· the pseudostatic analysis. The sliding stability for dynamic loading
conditions was also subsequently evaluated by determination of the maximum permanent
dynamic deformation for Case Ill (MCE) usjng the SARMA method of analysis.
3-15
Five loading combinati~ns were considered, as follows (Figures 3.11 through 3.14):
Case I
Case II
-Normal Reservoir -Usual Condition
1. Normal Max. Reservoir El 1180
2. Uplift and seepage forces
3. Dead loads
4. Ice at El 1179.0
Probable Maximum Flood (PMF) -Unusual Condition
1 . Max. Reservoir El 1· 191
2. Uplift and seepage forces
3. Dead loads
Case Ill -Earthquake -Extreme Condition
1 . Normal Max, Reservoir El 1180
2. Uplift and seepage forces
3. Dead loads
4. Ice at El 1179.0
5. Maximum Credible Earthquake (0. 75g)
. Case IV -Construction Case -Unusual Condition·
1. Reservoir water surface-at El 1065
2. Dead loads
3. Construction Condition Earthquake (0. 1 g) or wind load
Case V -Low Reservoir with Earthquake -Extreme Condition
1 . . Reservoir _below El 1130 (no hydrostatic)
. 2. ·Dead loads
· 3. Maximum Credible Earthquake (0. 75g)
'3-16
/
'·
Stability Re.quirements
Maximum allowable stresses and minimum required factors of safety are as specified in Table
3-4. These values are based on factors of ·safety as recommended in ·~Design of Gravity
Dams" for Usual Loadings, Unusual Loadings, and Extreme Loadings and·_ factors of safety
specified in project design criteria.
Table 3-4
SPILLWAY DESIGN FACTORS OF SAFETY ·
Stresses:
Concrete (f' c = 3000 psi)
Assumed Safety -factor
Compression, psi
Tension, psi
Rock (40 ksf = 280 psi)
Assumed Safety factor
Compression, psi
Sliding:
Shear-Friction in
Concrete
Safety factor
Case I
Normal
I
3;0
1000
60
2.0.
140
3.0
(in Concrete, C =300psi and at
Case II
PMF .
2.0
1500
90
1 .. 5
185
2.0
Rock/Concrete Interface, C = 1 OOpsi)
On Rock Foundation Joints
and Faults
Safety factor 4.0 3.0
3-17
Case Ill Case IV
Earthquake Construction
1.0 2.0
3000 1500
270 90
1.1 1.5
.250 185
1.0 2.0
1.2 3.0
Case V
Low Res.
1.0
3000
270
1.1
250
1.0
1.2
Table 3-5
SPILLWAY PSEUDOSTATIC ANALYSES RESULTS
Shear-Friction F.S.
Calculated
Min allowable
·Concrete Compression (psi):
Calculated
Mx' allowable
Concrete Tension (psi):
!:;ase I.
Usual
5.2
3
26.6
1000
!:;as~ II
Unusual
8.8
2
28.2
1500
!:;ase Ill ·
Extreme
2.6
1
69
3000
Case IV
Unusual
40.9
2
55
1500
Case v.
Extreme
4.9
1
70
3000
Calculated
Max allowable
(Reinforced)* 2.8 * * 63 (No Tension) 31 .3
Rock compression (psi):
Calculated
Max allowable
60 90
26.4
140
'28.2
185
270 90 270
69
250'
55
185
'70
250
* Tensile stress due to ice load results in cracking above El 1170. Below El 1170 stresses
without uplift are compressive.
**· Tensile stress due to· uplift. Stress without uplift is compressive.
Table 3-6
SPILLWAY FINITE ELEMENT ANALYSES RESULTS
Concrete Compression (psi)
Calculated
Max Allowable
Concrete Tension (psi)
Calculated
Max Allowable
Rock Compression (psi)
Calculated
Max Allowable
·CASE Ill
Base at: El 1130 El 1150
100.6
3000
126.8
270
100.6
250
58.6
3000
70.5
270
54.6
250
CASE V*
El 1130 El 1150
167.7
3000
115.4
270
167.7
250
94.6
3000
19.9
270
94.6
250
* Case V stresses based on MCE stresses for tension and MCE plus statically evaluated
deadweight stresses (52 psi at El 1130 and 25 psi at El 1150) for compression.
3-18
Table 3-7
SPILLWAY SARMA ANALYSES SUMMARY
Loading
Condition
Maximum Credible Earthquake
·Displacement
(ft)
C13se 1: 0 =A5°, .cohesion=O, No inertial water.force 0.37
Case 2: 0 = 45 ·,cohesion =0, Inertial Earthquake force of water us~d 0.52
Case 3: 0 = 45 ·,cohesion= 500 psf, Inertial Earthquake force of water used 0.28
The maximum calculated tensile stress is 127 psi and the maximum calculated compressive
stress is 168 psi, well within allowable stresses as specified in Table 3-4. The minimum
calculated shear-friction factor of safety is 2.6, also with a margin of safety to minimum
requirements. The maximum calculated MCE permanent mass. displacement, assuming a
hypothetical continuous and cohesionless failure plane, is small enough (6 inches) that it
would not result in breaching of the spillway. With the rock conditions and. extensive
foundatio'l surface preparation, the MCE is expected to result in no measurable permanent
base displacement.
Consequently, the spillway is considered stable under all given loading conditions.
3.3.3 Construction
The spillway foundation was excavated to sound rock. The spillw,ay is located in a relict
riverbed. of the Bradley River that is more jointed and weathered than the main dam
foundation. Consequently, grout takes were higher in the spillway foundation than in the
main dam foundation, taking twice as much cement in half the number of holes used in the
dam area.
Similar to the left abutment of the dam, poor rock quality in the rock knob between the
spillway left abutment and the dam right abutment resulted in an extension of the spillway
3-1.9
grout curtain. This extension connected the spillway grout curtain· with the main dam grout
curtain.
Total grout take for the spillway curtain (original plus extension) was 1 ,811 sacks in 58 holes
(1 ,938 linear feet).
The spillway was constructed essentially as designed. No significant problems or delays were
experienced. Performance of the structure during initial reservoir filling is.discussed in section
4.1, Initial Reservoir Filling.
3.4 POWER TUNNEL INTAKE AND ~HGH PRESSURE GATES
3.4.1 General Description
3.4.1.1 Power Tunnel Intake
The open channel from Bradley Lake to the power tunnel intake portal is approximately 350
·feet in length. The excavation for the channel begins at elevation 1230 and the bottom of
the channel is at elevation 1 026. This results in an overall depth of excavation of 204 feet.
The :channel was excavated as a series of benches 20 to 40 feet wide with 25 feet high side
slopes cut at an angle of 1 H:4V (Figure 3-15.).
3.4.1.2 High Pressure Gates
The high pressure gates are located in a vertical dry well type gateshaft located approximately
520 feet downstream from the· power tunnel intake portal (Figure 3-15).
The gates are installed in series. The downstream gate acts as the control gate, and will be
'
used in the event of emergency to close off the full flow in the tunnel. The upstream gate will
act as the guard gate. It will be used in the event the downstream gate fails or if there is a
need to service the downstream gate. Both gates will be closed during tunnel maintenance.
A by-pass pipe and a valve are provided to fill the tunnel after maintenance with the control
gate closed.
3-20
3.4.2 Design Parameters
3.4.2.1 Power Tunnel Intake
The power tunnel intake channel is a critical component of the project and is designed to
remain operating during maximum credible-earthquake (MCE) loading. Limited failures of the
upper benc~es and slopes of the excavation are allowable. The lower slopes and tunnel portal.
are heavily reinforced with rock support to maintain the intake channel configuration for the
MCE load. A rock trap immediately upstream Qf the tunnel portal is designed to prevent small
rock pieces from being transported into the tunnel and damaging the turbines.
-3.4.2.2 High Pressure Gates ·
The gates are the sliding type, approximately 8.5 feetwide and 11 feethigh, designed for a
static head of 1 60 feet, full generating flow of three turbine-generator units, hydraulic
transient conditions and other forces resulting from operation, such as downpull, etc. Design
of both gates is essentially the same. Each gate is operated by one hydraulic cylinder I oil
actuated, with an operating pressure of 2000 psi.· The gate speed is 1 foot per minute .with
the total closing/opening time of approximately 11 minutes. The cylinders and associated
equipment are located in the gatehouse at the top of the gateshaft .
. A bank of accumulators are provided as the pressure source for the hydraulic system. The
oil accumulator system is sized to operate each gate in one full stroke (close) without
recharging. One electric motor operated pump is provided.
3.4.3. Construction
3.4.3.1 Power Tunnel Intake
Excavation of the intake channel was completed to the design lines and grades with an
acceptable amount of overbreak. The rock quality in the intake is generally sound and widely
jointed. · Occasional shear seams to 12 inches wide were encountered but do not affect the
( rock slope stability. One year after excavation and prior to initial reservoir filling, the rock
3-21
/
I
slopes and benches of the intake channel were scaled and recleaned to provide additional long
term capacity for the accumulation of rock debris.
3.4.3.2 High Pressure Gates
The high pressure gates and related equipment and controls were installed essentially as
designed.
3.5 POWER TUNNEL
3.5.1 General Description
The power tunnel consists of the following (Figure 3-16):
• An upper tunnel 738 feet long that extends from the intake-portal at Bradley Lake to
a vertical shaft.
A vertical shaft 720 feet deep.
• A 17,605 foot long lower tunnel that begins at the bottom of the vertical shaft and
ends at the powerhouse. The downstream 435 feet of the lower tunnel is also
designated as the manifold section~ -.
• Approximately 520 feet downstream from the intake portal, the upper tunnel is
intersected by a gateshaft.
·The mani.fold section contains three wye-branch penstocks that end at the powerhouse. Two
of the penstocks are operational and the third is blocked and will be used for future expansion.
The penstocks, manifold section and the downstream 2,725 feet of the lower tunnel are
constructed with a steel liner encased in concrete. The remainder of the tunnel is concrete
lined.
3-22
(
\
1
The power tunnel has a finished 11-foot circular section from· the bell shaped intake to the
bottom of the vertical shaft including the lower elbow. The tunnel transitions to a 13 foot
circular section at the bottom of the shaft and remains at that diameter until it transitions to
the 11-foot diameter circular steeLiiner.
3 .. 5.2 Design Parameters
The power tunnel was designed as a fully lined conduit for an operating -pressure of 637 psi.
The lining is steel from the powerhouse to the point at which rock cover is equal to 6.0
percent of the operating pressure head in the tunnel at that point.
Thrustblocks are designed for each pensto.ck and the manifold to engage surrounding rock
mass and prevent the transfer of lateral load from the tunnel steel liner to the powerhouse
structure. Thrustblock design includes excavation of an enlarged chamber, installation of up
to 1 2 high strength double corrosion protected rock anchors and encasement in concrete to
provide additional mass resistance.
Drain lines installed behind the steel lined section prevent excessive external water pressure
from developing against. the liner during an unwatering of the tunnel.
3.5.3 Construction
The upper power. tunnel and the downstream 1400 feet of the lower power tunnel was
excavated by drill and blast methods. The vertical shaft was excavated by a 1 3-foot diameter
raise bore and 16,300 feet of the lower power tunnel was excavated using a 15.1 foot
· diameter tunnel boring machine. The gateshaft was excavated by drill and blast methods.
A detailed description of the excavation of the power tunnel can be found in the "Final
Construction Geology Report" May 1991 prepared by Bechtel.
Rock types encountered during excavation were essentially as predicted in the Geotechnical
Interpretive Report (GIR) prepared by SWEC and consisted mostly of graywacke with lesser
quantities of argillite with chert, argillite, intermixed graywacke and argillite and dacite.
3-23
Rock quality in the tunnel was better than anticipated, excavation proceeded smoothly and
minimal rock support was installed. Rock quality ranged from sound (joint spacing greater
than 3. feet) to highly fractured (joint spacing 2 'to 12 inches). Most of the tunnel was
excavated from sound to moderately fractured rock. Occasional intervals of highly fractured
rock and harrow shear seams 3 to 12 inches wide were also encountered .
. Joints open to as much as six inches were encountered in several thousand feet of the tunnel
immediately upstream of the end of the steel liner. These open features with a near vertical
dip and a strike subparallel to the tunnel alignment presented potential seepage paths for
water loss during normal plant operation.
High pressure grouting of these open features was performed from the end of the steel liner
to 3340 feet upstream where the ground water table is approxi_mately equal to the internal
operating pressures of the tunnel. The high pressure grouting was designed to fill open joints
and intervals of highly fractured rock to a depth of one tunnel diameter to create an annular
space of improved rock modulus and eliminate large leakage paths immediately adjacent to
the tunnel liner. Details and results of the grouting program are found in a report prepared by
SWEC entitled "High Pressure Compaction Grouting, Lower Power Tunnel".
Reinforcing was added to a total of 2285 linear feet of the concrete liner in the intervals of
highly fractured rock and open discontinuities to control cracking and deformation of the
concrete liner.
Cracks· in the penstock and manifold steel liner welds were detected during .routine
. nondestructive quality control testing. A change in weld filler rod resulted in fewer weld
cracks.
Radiograph tests were performs~ on all of the longitudinal and radial welds in the penstock
and manifold liner. All radiographed defects were cutout, repaired and re-radiographed.
Ultrasonic testing was ·also performed at critical locations and on a random basis. ASME
criteria were used to identify cracks and other weld defects detected using ultrasonic testing
that had to be cutout and repaired.
3-24
The manifold/penstock system was hydrostatically tested to approximately 1.5 time.s normal
operating pressure before encasement in concrete.
3.6 POWERHOUSE AND SUBSTATION
3.6.1 General Description
The Bradley Lake Hydroelectric· Project powerhouse has been designed to house two 60 MW
Pelton-type turbines with generators and associated support equipment and systems.
The powerhouse consists of a reinforced concrete substructure founded in rock and a
structural steel superstructure enclosed with insulated siding and roof. The structure is
approximately 80ft wide by 160ft long. The substructure extends from project El -9 at the
discharge chamber level to El +42 at the generator floor level. The superstructure extends
from El +42 to approximately·EI + 85 (Figure 3-17).
The substructure consists of the Generator Floor at El +42, the Turbine Floor at El + 21, and
sumps, pits and chambers associated with operation of the turbine located at lower levels.
The Turbine Floor, in addition to providing access to the turbines/generators, contains the lube
oil processing and storage facilities, the battery room, the emergency diesel generator and
other equipment associated with the plant operation. The Generator Floor consists of an open
. .
. 56ft wide bay serving the two generators with control equipment, and includes a lay down
and Service Bay, and a 24 ft wide Auxiliary Bay contains ·support facilities including the
Control (SCADA) Room, plant office., lunch room, locker room, toilets, and the machine shop.
The Generator Floor remains cl~;~ar and unobstructed with access for a 1 60 ton bridge crane
with an auxiliary 25 ton hook. The bridge crane can run the full length of the powerhouse.
Hatches are provided to. access lower levels. The Auxiliary Bay is designed to support a
secondary floor at El + 60 which houses HVAC equipment and provides room for storage.
The powerhouse substructure and .superstructure are designed with the consideration in mind
that a third 60 MW unit ma.y be adlded to the south side in the. future. Excavation of the rock
for the third unit's substructure was accomplished with the excavation for the first two units
to avoid future blasting near operational units. The excavated area was backfilled until the
third unit is installed.
3-25
The substation consists of a Compact Gas Insulated Substation (CGIS), transformers· and line
terminations on the powerhouse from the transmission system. The substation is adjacent
to and tied into the north wall of the powerhouse and as such may be considered an extension
to the powerhouse (Figure 3-18).
The CGIS is housed in a. reinforced concrete extension of the powerhouse and consists of a
11 5 kV, 4 breaker ring bus. ·The substation area serves as the line· terminals for two power
transmission circuits which.connect the powerhouse to the local utility transmission system.
Three main unit power transformers ( 11 5 kV) are mounte~ on concrete. pads, located adjacent
to the north wall of the extension housing the CGIS system. The transformers are provided
vyith separation walls and containment basins filled with crushed rock.
3.6.2 Stability Analyses. Assumotions and Results
The powerhouse was analyzed for stability against ov~rt.urning, sliding and floatation for the
following load cases:
CASE NO. CLASS
1 Normal
2 Unusual
3 Unusual
CASE NAME
Operating
.35g seismic
(DBE)
Storm tide
LOADING COMBINATION
-Substructure, superstructure, and
installed equipment weights
-Running or standby turbine operating
forces
-Tide at El + 4.0'
-Horizontal and uplift fluid pressure
-Fluid at El + 4.0' in the discharge
chamber
-Fluid at El + 11.5' in the clean water
sump
-Same as operating case except:
-.A 0.35g seismic event (horizontal)
-Same as operating case except:
-Tide at Storm tide El + 13.4'
Fluid at El + 5.0' in the discharge
chamber
3-26
t' 4 Unusual Servicing -~ame as operating case except:
' No operating turbine forces (spherical -
valve closed)
-Tide at Highest tide El + 11 .4'
-No fluid in discharge chamber
5 Unusual ·Construction -S~age I concrete weight only
-Tide at Highest tide El + 11 .4'
-Horizontal and uplift fluid pressures
-No tailwater pressure
-No fluid in discharge chamber
-No fluid in clean water sump
6 Extreme . 7 5g seismic -· Same as operating case except:
(MCE) -A 0. 75 seismic event (horizontal)
7 Extreme Sump empty -Same as operating case except:
-Tide at Highest tide El + 11 .4'
-No fluid in clean water sump
8 . Extreme. Construction -Same as construction case except:
with seismic -A 0.1 Og seismic event (horizontal)
9 Extreme 0.50g Vertical -Same as operating case except:
Seismic -A 0.50g vertical seismic event 1
,lr\ j
The factors of safety used for the above cases depend oh the class and are as follows:
Table 3-8
POWERHOUSE DESIGN FACTORS OF SAFETY
CLASSIFICATION
NORMAL UNUSUAL EXTREME
F.S. Floatation 1.5 1.2 1.05
F.S. Overturning 1.5 1.2 1.05
F.S. Sliding 3.0 1.5 1.05
Tension allowed .0.0 20 20
before cracking psi psi psi
/
3-27
/
The results of the powerhouse substructure stability analyses are as follows:
Summary of the factors of safety
and stresses Factors of Safety Uncracked Uncracked Cracked
Case Over-Toe Heel Heel
Case Name Classification Floating Sliding turning Stress Stress Stress
(ksf) (ksf) (ksf)
Operating Normal 3.14 24.97 2.57 6.8 12.6
.35g Seismic Unusual 3.14 7.16 1.78 16.6 3.7
Storm Tide Unusual 2.71 19.84 2.28 6.6 11.5
Servicing Unusual 3.83 62.71 3.19 5.3 14.6
Construction Unusual 2.04 62.71 1.54 6.5 1.2
.75g Seismic Extreme 3.14 3.98 1.32 27.6 -6.4 30.7
Sump empty Extreme 3.89 17.99 2.78 8.1 12.5
Construction Extreme 2.04 33.71 1.46 7.32 0.43
with Seismic
.5g vertical Extreme 1.23 18.89 1.1 1 5.79 -0.28
seismic
The stability of the powerhouse superstructure (structural steel) was analyzed by three
dimensional computer modeling. Individual member designs were based on the computer
analysis. These calculations are presented in the "Final Supporting Design Report" for the
powerhouse construction' contract which has been filed with FERC.
The powerhouse is considered stable under all given loading conditions.
3. 7 DIVERSION TUNNEL
3. 7.1 General Description
The 400 foot long diversion tunnel is located in the right abutment of the main dam between
the dam and the spillway. The gated tunnel is lined with concrete from the bell shaped intake
portal to the gateshaft. The gateshaft houses two high 'pressure gates installed in series. A
1 0 ft 6 in. diameter free standing steel penstock extends from the control gates downstream
to the outlet 'portal. The tunnel is constructed with a system of valves and nozzles at the
tunnel outlet to regulate flow releases. Valve-nozzle pairs mounted at a branch pipe from the
manifold are different sizes. Valves are either fully closed or fully open. They are sized so
3-28
(
' ' \ I
that by operating various combinations of nozzles, the flow can be controlled in increments
of approximately 5 cfs for any reservoir elevation within the operating range of El 1 080 to
1180. The valves are motor operated. Flow through the system is controlled remotely based
on measured flow through the Bradley River Channel.
The diversion tunnel, as shown in Fig~re 3-19, is designed to pass. Bradley Lake flows
downstream during construction of the main dam and to provide a means of lowering the level
of the completed reservoir at a controlled rate as required· during the project life in an
emergency condition. The tunnel. facilities provides minimum downstream flow releases for
the maintenance of aquatic habitat in the Lower Bradley River.
3.7.2 Design Parameters
In the case of a catastrophic earthquake, the lake has to be drawn down at a fast rate in order
to assess potential damage to the main dam. The design discharge for this mode of
operation is that required to draw down the reservoir in approximately 45 days, yet limit the
average rate of draw down to not more than 2.5 feet/day to prevent damage to the facing of
the main".dam. During an emergency draw down, an average lake inflow of 1500 cfs (two
highest flow months, July and August) and a no flow condition through the powerhouse are
assumed. The diversion tunnel high pressure gates would be fully open during this entire
draw down period.
Fish release facilities will be operated so as to pass the required fl.ow up to the total of 1 00
cfs.
Emergency draw down operation -
Initial reservoir level: El 1180
Lowered reservoir level: El 1090
Average rate of draw down: 2.5 ft/day
Reservoir inflow:
El 1180 to El 1080: 1,500 cfs
Below ·EI 1 080: 500 cfs
Velocity in lined tunnel: . .s_ 30 ft/sec
3-29
,
I
Velocity in steel penstock: ~ 80 ft/sec
Total draw down time: 45 to 50 days
Minimum fish flow releases -
Discharge: 50 cfs per pipe
Headwater: El 1 080
Tailwater: El 1065
3.7.3 Construction
The diversion tunnel and gateshaft were excavated by drill and blast methods. During
excavation of the diversion tunnel, several joints, open to 4 inches and filled with dense silt,
were encountered. Because the tunnel was operated in an unlined condition during
construction of the main dam and spillway, the possibility of the silt material eroding out of
the joints and causing tunnel instability was considered. The joints were cleaned out to a
depth of three times the opening width and backfilled with concrete.
Construction of the concrete liner, high pressure gates and the steel liner was completed
without major problems or delays. Two high pressure grout rings were installed in the
diversion ~tunnel.· The· upstream ring, designed to intersect the spillway-main dam grout
curtain had no take. The second ring, located immediately upstream of the gateshaft, had low
takes. Details of the geology and grouting of the diversion tunnel are found in the Bechtel
report "Final Construction Geology Report".
3.8 OTHER PROJECT STRUCTURES
3.8.1 Diversion Structures
3.8.1.1 Middle Fork Diversion
The Middle Fork Diversion is located approximately one· mile north of Bradley Lake in an
adjacent drainage at elevation 2160 on the Middle Fork Tributary of the Bradley River. The
Diversion consists of a.small intake basin and two reaches of open channel approximately 770
3-30
(
1 ••
feet and 480 feet long, separated by a stilling basin which is located in a natural bog area, all
of which was established by excavation. The Diversion conveys water from the Middle Fork
of the Bradley River to Marmot Creek, a tributary to Bradley Lake, and operates in all seasons.
3.8.-1.2 Nuka Diversion
Glacial melt forms a pond called Nuka Pool at the terminus of the Nuka Glacier. Nuka Pool
lies on the divide between two drainages, discharging water both into the Upper Bradley River
and into the Nuka River. Water discharged into the Upper Bradley River flows to Bradley Lake
and that which is discharged into the Nuka River flows to the Kenai Fjords National Park.
The Nuka Diversion improvements divert the glacial melt water flowing through the Nuka Pool
into the Upper Bradley River, except for an initial increment of flow which must be provided
to the Nuka River in accordance with the June 1986 Contract between the Alaska Power
Authority and the U.S. Department of the Interior. Per this Contract, the design must assure
that the first 5 cfs of available flow goes to the Nuka River. Flow in excess of 5 cfs is
diverted to the Upper Bradley River.
3.8.1.3 Upper Battle Creek Diversion
The upper Battle Creek Diversion is located approximately two miles south of the main dam
in an adjacent drainage at elevation· f34CY on a tributary to Battle Creek. The diversion
consists of a small dike, less than _1 0 feet in height, and a 250-foot long reach of improved
open channel within a 3800-foot long natural drainage. The diversion will convey water from
the base of a waterfall into Bradley Lake and is expected to operate on a seasonal basis.
3.8.2 Transmission Line
The project includes two parallel 11 5 kV transmission lines. The lines, called the
Bradley/Soldotna Line and the Bradley/Diamond Ridge Line, are each about 19 miles long and
extend from the new powerhouse north and west where they connect with existing
transmission lines. Each 115 kV line is supported by a total 78 X-frame steel structures, all
but 5 of which are guyed.
3-31
Fifty-seven (57) of the structures of each line are founded with driven steel piles (HP 12x53).
The guys for those structures are also anchored with driven steel piles. The other 21
structures of each line are located between the Bradley River and powerhouse in steep upland
areas where only helicopter access is available. The foundations for those structures, and the
guys, are anchored to the underlying soil or bedrock with No. 8 steel bars grouted into holes
drilled into the soils and rock. Seventeen (17) of those foundations for each line consist of
steel members supported on a reinforced concrete pad. The other 4 foundations are
reinforced concrete pads.
Initial designs for the transmission line structures and foundations identified structure and
foundation types, provided structure loading trees with general design criteria and load cases,
and provided general details for each structure and foundation type. Each foundation type
was designed to provide a window of structure to foundation connection elevations to
accommodate uncertainties in ground elevations at the structure locations. The contractor
performed ground surveys and designed and obtained transmission structures using the
general design criteria provided in the construction drawings and specificati~ns. Foundation
and guy anchor details (reinforcement, welds, member sizes, etc) were completed using
· · _/ specific design loads provided by the contractor's transmission structure vendor that were
based on the actual structures provided.
)
3.8.3 System Stabilization Equipment
As part of the Bradley Lake Hydroelectric project a Static Var Compensator (SVC) system will
be added at Soldotna and Daves Creek Substations. The Kenai 115 kV transmission system
. I
from Bradley lake to Anchorage is unable to reliably transmit excess Bradley Lake power to
Anchorage during off peak loading conditions when Kenai loads are minimal. The SVC
increases the export capabilities during these minimum load conditions.
A Static Var Compensator system is a very fast acting thyristor cqntrolled device that can add
shunt capacitance and shunt reactance to the transmission system to increase its capability
and reliability. The SVC will be in service by March 3, 1993.
3-32
2.25
rn
nJ
l/) 1.88
z
0
~ 1.50
0:: w
_j
w u 1.13
«t
_.J
<{ 0.75
0:: r-w
a... 0.38
lf)
0.00
\J '~~!
~
yf"'
~
~
1-"
I I I
RESPONSE SPECTRUM
FOR HYBRID EARTHQUAKE
~ ----·
~BRADLEY LAKE HYDROELECTRIC PROJECT
· MEAN RESPONSE SPECTRUM FOR MCE
(NEARBY SHALLOW CRUSTAL FAULT)
~~~ MEAN RESPONSE
\ r----_ FOR DBE
~ ~ ~ y--r--t--. ----t----. I ~
-
REF: WOODWARD-CLYDE CONSULT
REPORT: ''DESIGN EARlliQUAKE STUDY'
NOV 10 1 1981
---
SPECTRUM
-----
0.00 0.25 0:50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00
PERIOD (SEC)
MCE RESPONSE SPECTRA_,
MEAN AND CHOSEN
FIGURE 3-1
0.10
,, ..
\
~
>-" t-~ _J
c!l 0.01 r--.... ~ .......
0 ...........
0::: ............
CL f"..
w " u "' z
~ "~
~ "\ LLJ
,_J \ <t
::> z ~ z 0.001 <t \ ., .
\
\
'\
' \
\
\
\
0.0001 \
5 'K) 15 20 25 30 35 4C
WATER LEVEL (FT. ABOVE BRADLEY LAKE PROJECT DATUM)·
ANNUAL PROBABILITY OF EXCEEDE·NCE FOR
·WATER LEVELS DUE TO TIDE AND TSUNAMI
FIG RE -u 3 2
G.OO,
REFERENCE DATUM MLLW OF BEAR COVE
GENERALIZED TSUNAMI WAV:E
FORCE DIAGRAM
'------------------.c:::: .. _. FIGURE 3-3
/
\
D.ESIGN LOAD
(I) MAXIMUM WAVE ELEVATION ~ 25.0 1
FOR AN EVENT WITH AN ANNUAL
PROBABILITY OF 0.007.
TOTAL DYNAMIC FORCE
= 192 KIPS/FT
POWERHOUSE
..
CROSS SECTION
TSUNAMI WAV.E
DETAILING
HEIGH-r:
EL42'
EL MINUS91 S
ESTIMATED
FIGURE 3-4
1 0 1 2MILES -----BRADLEY LAKE
SHOWING THE LOCATION OF
THE POTENTIAL SLIDE AREA
FIGURE 3-5
Bradlei
lake
Surface
Bradley lake
Bradley Glacial Bands
+
,-
'f/ 1220\ I > .... _)
1 ,,/ Adjusted
,....--'{" Middle Fork
(214 J ,.,.....
Sign Change
(a) BRADLEY RIVER
Wolverine Glacial Bands
Wolverine Creek
near Lawing
(observed)
8
,(
Middle Fork
Glacial
Bands (b)WOLVERINE CREEK
LEGEND
0
0
D
BASIN OR SUBBASIN
COLLECT POINT
RESERVOIR SCHEMATIC OF
SSARR MODEL
FIGURE 3-6
SURFACE-SUBSURFACE SPLIT
1.5
....
::::!
0
.<:: .._
1.0 VI ~ QJ
.<:: ~ c..; c: ~'b ~0 .....
I c: ..... ~0 QJ
::::! u
0. ...
<:: QJ
~ 0.5 "-
QJ .... u ....
"' "'ac.\a' 0 .... .... c:
::::!
::::! 0::
Vl
0
0 0.5 1.0 1.5 2.0
Surface & Subsurface Input-inches/hour
EVAPOTRANSPIRATIO~ INDEX
.15
Nonglacial .... ....
>,
"' ..., 0
<::
::::!
0:: .._
.10 VI
QJ
.<:: u Gl aci a 1 c:
~
{'..
I .... <::
0 0
~
"' ... .05 0 c.
"' >
... c:
QJ u ...
QJ
"-
LLI c:
ll:
0
0
r;::
"' J F M A M J J A s 0 N 0 VI
"' co
I~ on th s
SOIL MOISTURE INDEX
100 -tT--
Glacia~ -r~-·v
50 ..... "' -t?'
--?
:t
-If\=
00 5 10 IS
Soil r~oi sture Index-inches
BASE FLOW INFIL TRAT!Oil INDEX
100 1--' -
Glacial
50
= 1=1= -T. . ~onglacial
0 % 0 4 6
Base flow Infilitration Index
... c:
QJ u ...
QJ
"-
c:
"' f ..: ...,
QJ ...
QJ > 0 u
ll:
0 c:
Vl
~ ...,
I
"' .. ..., ......
VI ..
..0:: u c:
I .. ... ...
D:
.....
a;
::0::
SNOW COVER DEPLETION
100 ''f'' ----~------------ -
-* ~ -so o_,
;s:>{.
~= ---~~
II
0 50 100
Accumulated Runoff in Percent
MELT RATE INDEX
.10
-Glacial
.05
\a' :\a c. \\01\q
0
0 50 100
Accumulated Runoff in Percent
BASIN CHARACTERISTICS
FOR SSARR MODEL
FIGURE 3-7 -
/
J 5-1-
--.,_PROBABLE MAX. FLOOD INFLOW(31,"700CFS
3 0
;
i I
2 5--
\ SPILLWAY DESIGN OISCHARGE(~.800CFS).
'
~0-1-\
' \ \
I"' \
1/ ,; I 1\ \ I 195
/: 1\ \
1o...:.,_ r MAX. WATER SURFACE ELEV. !1190.65 Ft)
1-w w 0
~ v ~1\~ I
1/ Ill ' .... ~ I I
I ,),-" I
5--v ,J---~ ~x --+-~Jt -~-~I I ~ ""-+---~--~-vr· I ')...· , I I' -~ v. -· _j_ ·----· / I __ l_ I
-~ 1
"r----v
rt ~ i
RFI'PIT I :riO~ If' 75' i II ill I _.,.. 1--·. i I Ill ~ i i :I -ol .. 1-e :lit~ u. n. . -g• ol4 0 I~ &SO '1'-(.1. I lr\ 18-olf1l\l'•l l'lo Zl f6' 2
:" H' 1: i3 15 I " .. .. 14
190 .lL
z
IB5 Q.
1-~ w
_J
160 w
~1)111\S
DURATION (DAYS) PROJECT DESIGN FLOOD
PROBABLE MAXIMUM AND SPILLWAY DESIGN FLOODS
FIGURE3-8
)
FILL T'fPES
1• PROCE!>SE.P CRU~ED SlOt£ EMBANKMENT
JI'J'MA.1IC ROCK ~11.:.1.· GAP GRAD£0 DRAIN
16'MAX ROCK FILL
:?<!'MAll' ROCK FILL
48"MA.ll ROCK.Fl.l (QVERSIZEJ
2.000 ~ V.ElGHT RIPRAP
40 W.,WEIGHT RIPRAP
TYPE Bl FILL
PE 85 FILL
CONC FACE SLAB
1'·0' THICK
TYPE 84 FILL
fJ
MAXIMUM DAM PROFILE
RFI~lFORCED
/
COI'-K:RETE
FJ>CE SLABS
~IGHT ABlJTf.'!ENT PLINTH
I
I
~ I ~-I S GMENT B SEGMENT 0 ~-r-~~.l.N
~~~ / ----__../ VIEW lOOKING DOWNSTREAM---------. . .
~;;;p
TOE PUNIH
.f::
2-2
).] kz.,-'
~--. .I
6' ttf
WAIERSioP
H
1-1
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
CONCRETE FACED RCCKFILL DAM
SECTIONS AND DETAILS
FIGURE 3-9
RM 42 N 2103945
RM~) fl210)817
OH 7 N 210)7'!>0
Dtl Jl N 210)774
PLAN
<;CAL( A
SECTION 4-4
SCALE B
U/S CREST
-~·2~
Yc: 0.99'
Rlo 5.68'
R2:1.72'
SECTION 1-1
SCALE B
SECTION 3-3
SC"-E B
VENTILATION SHAFT
& EMERGEN:Y EXIT
~"f..SPil.LWAY
I 59.93'
li'H(Rfo.'EOIATE TRAINING WALL TO
MATCH tc.R.
DIS CREST COOI'lOINATES
' 0
00.0
2.00
300 •oo
·o·-·-
""' 600 ,00
6UO
9 00
IQ.f)O
I 1 00
'""' 0)00
14-00
TCI 15.07
'
PCI 2242
PI I 26.92
Pll 34.13
0.07
0-24
0.02 o.ea
l.JJ
1.86
2.<017
106 ,., .,.
»o
&69
7,76
690
10.19
PC2 1~.41 1562
1-'12 4292
PT2 '54.91 4500
O 20 40FEET
GALES:~?
60F'EE1
'iCALE A: 1": o\0'
y LAKE HYOAOt:lECTRIC PROJECT
BAAOLiLASKA POWER AUTHORITY
SPILLWAY
PLAN, ELEVATIONS 8. SECTIONS
SlOH£ & WEBSfEA & EI'OGIN£ER..O CORPORATIOI'O
FIGURE 3-10
CASE I -NORMAL RESERVOIR
RESULTANT PRESSURES INCLUDING UPLIFT
(psi)
\7 WS EL 1180
EL 1175
3.6 psi
TENSION
EL 1160
1.1 psi
iENSION
EL 1150
3.2 psi
EL 1140
re~
ELII3~ ~~~~~~~~~~;:~:;~~~~~~~~~
16P8i
EL 1124
9.7JIIi
NOTE:
GALI.ERY SLAB ISOLATED FROM STRUCTUR!
SO WIU. NOT PROVIDE RESISTANCE. SLAB
DEBONOEO FROM ROCK SO ACTUAL. UPUFT
WILL BE NEGLIBILE (TYP),
STATIC ANALYSIS
BASE EL 1124
FIGURE 3-11
i
CASE IT-PMF
RESULTANT PRESSURES INCLUDING UPLIFT
(psi)
'\} WS EL 1191
EL 1180
0.3 pai
EL 1170
0.9pai
EL 1160
I. <4 psi
EL 1150
3.4 psi
EL 1140
I~ pai
EL 1135
II pai
EL 1124
f'-....1--~--J........L...J
I
} CREST
I
STATIC ANALYSIS
BASE EL 1124
FIGURE 3-12
r' CASE Ill -EARTHQUAKE, EXTREME CONDITION
· (0.75g HORIZONTAL)
RESULTANT PRESSURES INCLUDING UPLIFT -
(psi)
\7 WS EL 1180
EL 1175
1.1 psi
TENSION
EL 1150
:3.2 psi
EL 1140
I !I psi
16 psi
NOTE:
I
I'
GALLERY SLAB' ISOLATED ~M STRUCTURE
SO WILL NOT PROVIDE RESISTANCE. SLAB
DEBONDED FROM ROCK SO ACTUAL. UPUFT
WILL BE NEGL.IBIL.E (TYP),
BASE EL 1124
FIGURE 3-13 __ .__.
/
CASE ISZ ~ CONSTRUCTION
{ 0.1 g HORIZ)
RESULTANT PRESSURES
(psi)
I.
EL 1180
EL 1170
9.6 psi
EL 1160
18.5 psi
EL 1150
27.1 psi
EL 1140
4~ psi
EL 113~
48 psi
GROUND
ACCELERATION
·BASE EL 1124 .
FIGURE 3-14
lf----1-''-"-"-1~ 1'-0"NOMINAL
CONCRETE
UN lNG
,,
-~------------~-..,-.... -....------
1 .:. • ' .--~-.
r .. -.·--
---·---{TUNNEL
__ _L_EL 1030'
------0~,,. .----------GROUNDL~--
TRANSVERSE PROFILE
~ INTAKE CHANNEL
/
~P-.IC. /"
GROONDL•y/
,/'/
,/-
DIVERSION LAI':f: LEVEL "
DESIGNSI...t+1ER BASE /~TEMPORARY
FLOW EL 1076 .-. ROCK PLUG ~ /\ ,. \
TUIY.I£1. AIR VENT
"TUN,..EL
ARCTIC ENTRAtiCE
LADDER
\
LONGITUDINAL PROFILE
PLOT PLAN-GATE SHAFT . --Ml'=?.;;s=s
GATE HOUSE FLOOR PLAN
PLAN
GAfE CHAMBER
• -~· Of
e7 .. ·---_:::s
. . ~
PLAN
EL 1053.50'
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
INTAKE CHANNEL&.
POWER TUNf'JEL GATE SHAFT
SECTIONS 8. DETAILS
FIGURE 3-15
8221-6
VPP[R
'''""" TUNNEL
r
LOWER POWER TUNNEL
OPTION ZONE
INTAKE DETAIL
1~-l-.IIIIL---~-MANIFOLD
HORSESHOE
EXCAVATION
AT UPPER j
POWER TUNNEL -----J
I
OPTION B
TUNNEL
L ___ _
PLAN
SCALE A
WALI'WA'fl,lll[
El ~~·;o·
PROFILE
POWER TU'*'{L
SCALE A
Bl'Ll o.<:O'i£ I'AVLf
T\JNNEL
';!PilON lONE
\_DRILLED
DRAIN
HOLE
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
POWER CONDUIT
PL.I'I N J PROFILE & DETAILS
FIGURE 3-16
6'-6" OIA PENSTOCK
IN TRENCH
~ STL Ur-.ER t•:.t.~!.':_~' -;. .•.•' ':\TUNNEL
---:. ·-•-•. ::__LINER
• ,• lit<ASED IN ·~-w~ CONC'f >E
rt.ORA>N > ""
11' OIA STEEL LINER
';--.-;;;;;;'~an er
PENSTOCK, MANIFOLD & POWERHOUSE
~~,;o;;;;;-:;j~FEET
~IFUTUREl
~[L4!•
FUTURE UNIT EXCAVATION
ELlS'
~-r-r---o---.r-'
so• o~ ----. -~ ·. --------___.----1 )1• 0" UNif'i
-~
~1~" / ..
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
I 3. o MW PELTON POWERHOUSE
FIGURE 3-17
~327000
PLOT PLAN-POWERHOUSE SUBSTATION
-----«JQ!lll
NO 00.0 E
TOWEilS
NO OEAO E
tOWER s
-----.JI]!II]
-----«JQQQ
~)27000
("' (~ /
OISCONNC:CT
SWITCH
~v ( \_
PLAN
TYPICAL TRANSMISSION STRUCTURE
o 10' ~o· l'lo................ -~3
s.;;.>Lt':t.IH[T
"l' ~
"""" il'
"""" """""
\""'
OISCONNt:CI SWITCH
ON OEAO ENO IOV.OERS
CROSSING
/WOODEN H-TCM'ER
!""' CROSSING
OISCONr.ECT SWITCH
ON~O E~OWERS
[
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
POWERHOUSE SUBSTATION AND
BRADLEY JUNCTION
FIGURE 3-18
____________________________________ ______j_ ________ __j
EL !069 0'
PROBABLE MAJtiMUM F'LOOO LEVEL EL 11906'
NORJ..IIAL MAXIMUM OPERATING RESERVOIR LEVEL EL 1190 0'
E.IITSJING GROUND
LINE IAPPROXI I
I
• I
I
I
I I
I I ~ti~1~!~ ;1
:
G'OUHNG~
I ELI0965'
I· I I Ill I I I I
/ I GROUr RINGs-{ 1 I ~ I I I
EJtl$fTNG GROUKO
LIN[ (APPROXJ
ROCilF'ALL BENCH
EL 1120.0'
EL 1062.5'
/~~=L~~~--~~~==~~~;t~~~~~~~~~~~~~~~::~~E~xc~~~·:n~o:•~~,·,~a~w~==~~~~~~~~~~~~iE~~~~ii~ii~~~~~~~~~~'~'-'oso.o' ___ / I{ cELT0761F SPFl;TNGLINE
---------------_---_----::...---------------
II I 28''0 IFISHVIIA.TER
,_,
SCALE A
/ 8Y·PASS PIPE a~~! 1 r
DIVERSION TUNNEL SECTION
2-2
fUp.jN[l.
PLAN OF TUNNEL
SCALE 9
3-3 4-4
SCo\LE A
5·5
SCAt.[ A
20 40 I'"EEf
=:::?
•(Jj
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER A.I~Tc:.H:::O::;R::;IT:..:Y ______ -1
J)IIIE:IlSIVrJ "fU.IJIIIEL
SECTIONS AND DETAILS
FIGURE 3-19
START UP
4.0 START -UP
4.1 INITIAL RESERVOIR FILLING
The reservoir filling was.initiated at 5:00PM on October 30, 1990 with the lowering of two
diversion gates. Because of the low streamflow observed downstream in the Lower Bradley
River salmon spawning area, one of the gates was opened at i 0:00 PM the following day.
Low streamflows required the installation of a temporary construction fish water bypass
system until the semi-permanent bypass piping system could be installed. Low inflow into
the reservoir .due to unseasonably cold temperatures necessitated virtually all inflows to be
passed through tbe temporary construction fish· water bypass system. Consequently, the
reservoir level rose and stabilized at only 0.3 feet during the month of November. In
December there was a freshet and the water level rose from EL 1 072.45 on December 1 to
EL 1073.2 on Decem~er 30, 1990. On August 1, 1991 the reservoir elevation was 1145.20
and on September 1, 1991 .the reservoir elevation was 1163.40. The final reservoir reading
for this report is 1179.5, made on September 25, 1991. See tables 4-1 for reservoir filling
readings.
4. 1 . 1 Settlement Survey Monitoring
Settlement of the rockfill dam was minimal. Maximum vertical settlement was 0.07 feet and
maximum lateral deformation in the downstream direction was 0.03 feet. Graphs of
settlement and lateral movement measured along the dam crest, upstream face and
downstream bench are given in Figures 4-1 through 4-8. Tabular summaries of settlement
data are given in Tables 4-2 through 4-7. The movements observed are very small and are .
well within acceptable limits.
Measurement of dam and spillway settlements will continue on a semi-annual· basis , to
evaluate the seasonal and long term performance of the structures:
4-1
/ 4.1.2 Spillway Seepage Monitoring
Seepage from the spillway foundation drain curtain is collected into a discharge channel and
passes over a V-notch weir (See Section 5.1.2). The foundation seepage discharge was
monitored daily during the initial reservoir filling (Table 4-8).
The reservoir pool reached the level of the V-notch weir at El 1135 on July 17 ~ 1991. No
seepage was observed until fourteen days later on August 1, 1991 when the reservoir pool
reached El 1145. As the reservoir level continued to rise, the spillway seepage increased
steadily from less than one gallon per minute (gpm) to approximately 40 gpm (Figure 4-9).
Seepage has stabilized at 40 gpm with the reservoir at approximately maximum normal
operating pool.
This sustained seepage rate of 40 gpm is well below the maximum allowable seepage rate of
100 gpm. Monitoring of the spillway seepage rate will continue on a regular basis as part of
the routine operation of the facility. Should the seepage exceed the maximum allowable limit
of 100 gpm, an evaluation of the data should be performed to determine the cause of such
an increase.
4.1.3 Visual Inspection
Daily visual inspections of the dam, spillway and diversion fish water by-pass flow were made
during initial reservoir filling. The reservoir shoreline was also visually inspected periodically.
No structural problems were identified during the inspections of the impoundment structures.
Visual inspection of the reservoir shoreline during initial filling revealed stable slopes with no
indication of rock or soil slides. Floating debris consisting of brush, lumber and roots
accumulat.ed at the dam and spillway. Some of this debris passed over the spillway and was
deposited downstream of the spillway apron when the reservoir level rose above El 1180 and
flow was released over the spillway.
4-2
j
4.1.4 Diversion Tunnel Performance
The diversion tunnel performed as designed during the initial reservoir filling until the water
level rose above El 1180 and water began passing over the spillway. At this time water
inflow in excess of 200 gpm was observed issuing from one of the rock drain holes
immediately downstream of the gateshaft. Once the reservoir level fell below El 1180, water
inflow from this hole was reduced to a nominal flow. The flowing drain is located in the right
(spillway) side of the tunnel above springline. The water inflow is believed to be attributed
to an open rock joint that is exposed downstream of the spillway structure in the spillway
channel and extends to the drain hole. This leakage and means for repair will be evaluated
at a later date.
4.2 Initial Tunnel Filling
Initial tunnel filling was performed in May 1991 . The initial tunnel filling was conducted at
a controlled r.ate with 18-hour hold periods maintained for every 1 50 feet of rise in head until
water reached the El 700 ft level. Above the El 700 ft level 60-hour hold periods were
maintained for eyery 150 ft of rise in head.
When the water level reached El 800 in the vertical shaft a constant head leakage test was
performed. A flow rate of 2000 to 3000 gpm was required to maintain the water surface at
El 800. This leakage rate is interpreted to be due to the recharge of the water table that was
drawn down during construction of the tunnel.
After the constant head test was completed, filling of the tunnel continued until reservoir level
at El 1076.5 was reached.
Three weeks after the tunnel was initially filled a falling head test was performed on the
tunnel. The water level was drawn·down to El 998 prior to starting the test so the free water
surface was in the shaft. The fall in the water level in a period of 12 hours was measured.
The average flow (leakage) out of the tunnel during this test period was calculated to be 58
gpm (Table 4-9). The results of the falling head test indicate that the groundwater table in
4-3
the surrounding rock has been reestablished and the power tunnel will perform with minimal
water losses.
The penstock drain lines were monitored during the initial tunnel filling. All of the four drain
lines were flowing at a total rate of about 225 gpm. This flow rate did not change during the
filling and are performing as intended. Because the drain lines are flowing at 1/3 to 1/2 full,
the flow meters are not functioning properly. Penstock· drain line flow rates are currently
visually observed. Flow rates have stabilized at 225 gpm measured during initial filling. This
seepage rate is one half of the maximum allowable seepage rate of 449 gpm (1 cfs). ~low
from the penstock drain lines will be monitored continuously by SCADA. If the seepage either
exceeds the maximum allowable limit of 449 gpm or suddenly increases at full reservoir, an
evaluation of the data should be performed to determine the cause of such an increase.
4.3 POWERHOUSE
4.3.1 Summary
A comprehensive testing program was performed on the turbine-generator units to ensure that
they meet the contractual specifications and guarantees, and perform as designed. The
program included tests performed to meet operational requirements of the Rail belt Utilities as
outlined by the Technical Coordination Subcommittee.
The test program was structured in three phases, Generic Testing, Preoperational Testing, and
Startup Testing. Generic Testing and Preoperational Testing of contractor furnished
equipment was performed by the various construction contractors under the direction of the
Construction Manager. Preoperational Testing of owner furnished equipment, SCADA system
and turbine-generator units, and Startup Testing was performed by SWEC.
The test program began with reservoir filling on October 30, 1990. Generic and
Preoperational testing occurred during the winter of 1990-1991. The transmission line and
station electrical systems were energized in early January 1991. The units were turned over
to begin unit testing in March 1991. Tunnel filling began on April 19 and was completed on
April 30, 1991, 13 days ahead of schedule.
4-4
Unit 2 was rotated for the first time on May 15 and Unit 1 on May 18. The units were
synchronized to the system on June 20. All testing to ensure that the units met their
contractual and performance requirements were completed by August 29, and the units were
· turned over to Chugach Electric Association (CEA) Dispatch for testing on August 1 , 30 days
ahead of schedule. The station was declared commercial on September 1, 1991, or.
schedule.
There were two major problems encountered· during the startup with the equipment. The
governor needle sequencing control caused power swings of as much as 20MW when the
needles sequenced from two to three to four to six needles in operation. The governor
algorithms were modified and these swings reduced to 1-2MW. The turbine efficiency meets
the guarantees at the peak efficiency point, but is approximately 0. 7% low at full power. This·
problem is discussed further in Section 4.4, Turbine/Generator.
4.3.2 Test Organization
( The test organization consisted of representatives of four project organizations; AEA, SWEC,
Bechtel, and the construction contractors. The construction contractors were responsible for
construction testing, and Preoperational Testing of equipment and systems furqished by them.
SWEC and the AEA performed Preoperational Testing of equipment provided by AEA. Bechtel
supervised and witnessed testing performed by the contractors and recommended systems
for turnover to SWEC as complete and ready for further testing. Craft support for testing by
SWEC was provided by the contractors at an hourly rate.
,'
The testing program was structured in three phases.
Generic Testing: These tests were performed by the contractors to verify the quality of the
construction and ensure that the equipment and systems are ready for further testing. These
tests included wire and cable checks, hydro-testing, control circuit tests, piping cleaning and
flushing, and system physical inspection and verification.
Preoperational Testing: Systems and equipment provided by the contractors were
operationally tested and placed into operation by these procedures. The procedures included
4-5
I
'•
a step-by-step control system checkout and system performance test. Preoperational Testing
· . .___ of equipment furnished by AEA, the SCADA system and turbine-generator units, was
performed by SWEC in conjunction with the AEA operating staff.
\ , __ .
Startup Testing: Startup Testing consisted of those tests re.quired to place the units and
station in an operating condition. Tests were performed to verify that the equipment and
systems performed as designed and as required by AEA. At the end of Startup Testing the
units were ready for dispatching by the utilities and commercial operation. Included in this
phase of the testing were tests requested by the utilities Technical Coordination
Subcommittee to verify operation of the station on the system.
A Startup Manual was prepared by SWEC to outline the scope of the entire program. This
manual provided procedures and control for the program to. ensure that the objective of a
commercially operational station was met at the end. The manual consists of four volumes.
Volume I-Administrative Procedures: These procedures describe the structure of the
test program, safety and jurisdictional tagging to be used, and the jurisdictional turnover
process to be used for control of systems.
Volume II -Generic Test Procedures: Mechanical, electrical, and instrumentation.
Volume Ill-Preoperational Test Procedures: Section 1 Procedures for the General Civil
Contract (Enserch J.V.); Section 2 Procedures for the Powerhouse Contract (H.C.
Price); Section 3 Procedures for the Transmission Line Contract (Newbery); and Section
4 Procedures for AEA furnished equipment (SWEC).
Volume IV-Startup Test Procedures: For integrated plant testing and unit performance '
testing.
4-6
' \
4.3.3 Schedule
A schedule was prepared by SWEC in the fall of 1990 for testing and turnover by the
contractors to allow testing of the project in a logical sequence and meet the contract
milestones and commercial operation dates. The contractor:;' construction schedules did not
allow for this preferred testing sequence, however they were able to meet key dates in the
SWEC schedule. The testing sequence was modified to reflect the turnover dates scheduled
by the contractors and the final startup schedule developed. Key early finish milestone dates
in the schedule were:
Begin Reservoir Fill
Transmission Line Energization
Plant Energization
Tunnel Fill
Unit 1
Unit 2
Turnover for Preoperational Testing
First Rotation
Synchronization
Load Rejections
Commercial Operation
Turnover for Preoperational Testing
First Rotation
Synchronization
Load Rejections
Commercial Operation
1 Nov 90
30 Nov 90
25 Dec 90
13 May 91
9 Mar 91
25 May 91
17 Jun 91
5 Jul 91
31 Aug 91
1 Mar 91
23 May 91
·14 Jun 91
3 Jul 91
1 Aug 91
These early dates allowed almost 40 days of slack to meet the September 1, 1991 station
commercial operation date.
The Transmission Line Contractor was unable to turnover the line until late December 1990.
Due to the Christmas holiday it was decided to delay ~nergization until January 1991.
The Powerhouse Contractor had difficulties meeting its turnover commitments for the turbine-
generator systems. This caused a late start of Preoperational Testing of the units of 12 days.
4-7
Water inflow to the reservoir after the gates were closed was less than anticipated. It became
\ _j apparent in May of 1991 that sufficient water would not be available to develop the head
necessary to operate the units at full load for load rejection testing as scheduled. Water
inflow was projected and coordination made with the utilities outage schedules and the load
rejection tests were rescheduled for second week of July, depending on availability of
sufficient water.
j
During June of 1991, the utilities requested that Startup Testing be complete and the units
be made available for their operation by August 1. This required a rescheduling of the startup
program. After discussions with the TCS, it was decided to complete all startup testing
necessary to prove the units by August 1, and that the tests requested by the TCS to
demonstrate operation on the system would be completed in August with commercial
operation of both units scheduled for September 1 . The following milestone dates were
developed:
Unit 1
Unit 2
Synchronization
Load Rejections
Acceptance Tests .
Synchronization
Load Rejections
Acceptance Tests
Units ready for Dispatch
Commercial Operation
The following dates highlight the actual progress of the testing program.
Com·mence Reservoir Fill
Transmission Line Energization
Plant Energization
Tunnel Fill Complete
Unit 1
Turnover for Preoperational Testing
First Rotation
Generator Initial Tests
Synchronization
Load Rejections
Acceptance Tests
4-8
20 Jun 91
12 Jul 91
25 Jul 91
20 Jun 91
18 Jul 91
22 Jul 91
26 Jul 91
1 Sep 91
30 Oct 90
9 Jan 91
10 Jan 91
30 Apr 91
13 Mar 91
20 May 91
1 Jun 91
20 Jun 91
11 Jul 91
29 Jul 91
/
/
Unit 2
Turnover for Preoperational Testing
First ·Rotation
Generator Initial Tests
· Synchronization
Load Rejections
Acceptance Tests
Units Turned Over for Dispatch
90MW Two Unit Run
90MW Two Unit Load Rejection
Commercial Operation
4.3.4 Results
7 Mar 91
17 May 91
5 Jun 91
20 Jun 91
16 Jul 91
22 Jul 91
1 Aug 91
14 Aug 91
16 Aug 91
1 Sep 91
The test program is documented in the completed test procedures turned over to AEA. The
pertinent data obtained is summarized below. Test results for both units are well within the
guarantee or design values with the exception of the turbine efficiency.
Unit 1
Bearing Vibration After Balancing
(Maximum allowable 40u-m, zero to peak)
Bearing
Turbine
Gen Lower
Gen Upper
Thrust
Vibration
(u-m, 0-P)
0.4
2.5
5
Shaft Runout (Maximum allowable % bearing clearance)
Gen upper
Turbine
.03mm
.01mm
Unit stop time (with brakes and brake jet) -6min 30sec
Generator Parameters
Direct Axis Synch Reactance (Xd)
Negative Sequence Reactance (X2 )
Zero Sequence Reactance (X0 )
4-9
Design
0.80
40
16
Clg Wtr Inlet
Actual
0.75%
36.23%
15.95%
,
\ ,_ '
''·
Unit 2
Short circuit ratio 1.2
Wave Form Deviation Factor 10%
Telephone Influence Factor
Balanced 70
Residual 50
Heat Rise
With All Coolers 75°C
One Cooler Out of Service 75°C
Load Rejections
Max Penstock
Load Speed Pressure
(%/MW) 'startlmax} 'startlmax}
10%/6.84MW 300/303rpm 482/491 psi
25%/16.63MW 300/306.8rpm 483.5/487psi 1
50%/30.1MW 300/31 0.8rpm 478.7/502.9psi
75%/45.0MW 300/317 .3rpm 474.3/516.6psi
1 00%/60.84MW 300/323.9rpm 464.6/518.5psi
1 . Tested on .a different day than others at a higher reservoir elevation.
Efficiency
Guarantee
Turbine -Peak 90.7%
Turbine -Full Load 89.8%
Generator 98%
Bearing Vibration After Balancing
(Maximum allowable 40u-m, zero to peak)
Bearing Vibration Temp
(u-m, 0-P)
Turbine 0.3 132°F
Gen Lower 3.5 122°F
Gen Upper 3 125°F
Thrust 142°F
Shaft Runout (Maximum allowable Y2 bearing clearance)
Gen upper
Turbine
.04mm
.04mm
4-10
1.33
0.43%
2.6
5.7
63.5°C
72°C
Max
· Gen Volts
'startlmax}
13.31/13.458kV
13.46/13.629kV
13.44/13.529kV
13.2/13.497kV
13.22/13.484kV
Actual
90.57%
86.1%
98.2%
Clg Wtr Inlet .
43°F
43°F
43°F
43°F
Unit stop time (with brakes and brake jet) -Gmin 25sec
Generator Parameters
Direct Axis Synch Reactance (Xd)
Negative Sequence Reactance (X 2 )
-Zero Sequence Reactance (X0 )
Short circuit ratio
Wave Form Deviation Factor
Telephone Influence Factor
Balanced
Residual
Load Rejections
Load
(%/MW)
10%/7.92MW
25%/15.34MW
50%/30.96MW
75%/45.36MW
1 00%/62.28MW
Efficiency
Max
Speed
(start/max)
300/303.2rpm
300/307 .4rpm
300/31 2.8rpm
300/317. 7rpm
300/316.8rpm
Design
0.80
40
16
1.2
10%
70
50
Penstock
Pressure
(start/max)
481 .8/489. 7psi
481.2/487 .9psi
480.6/49.0.5psi
477.4/---'
466.1/519.8psi
Guarantee
Turbine -Peak 90.7%
Turbine -Full Load 89.8%
Generator -Not tested due to acceptable result Unit 1 :
4.3.5 Problems Encountered -Changes Made
Cooling Water Systems
Actual
0.76
35.90%
16.28%
1.32
0.83%
5.1
2.9
Max
Gen Volts
(start/max)
13.42/1 3.459kV
1 3.44/13.659kV
13.50/15.200kV
13.34/15.031 kV
13.28/14.060kV
Actual
90.5%
87.1%
During Preoperational Testing by the Contractor it was found that the Service Water Pumps
did not provide the required flow of 500 GPM. Flows were measured using the ultrasonic
flowmeter of 420 GPM. The pump manufacturer stated that the pump impellers could be
lowered in their casings to increase the discharge flow. It was determined that decreasing
the lower impeller clearance by lowering could be detrimental to pump life. During the
generator heat run and subsequent operation cooling water temperatures in .the closed loop
4-1 1
· were monitored. Since all temperatures were within the design criteria it was decided that
\_../) the pump flow was adequate and the impellers should be left as is.
i
I
\.. /
During the generator heat run on Unit 1 it was noticed that the pressure control valve
provided for the bearing oil coolers fought with the temperature control valve provided for the
generator air coolers. To continue testing, the bearing cooler pressure control valve was
placed at a fixed position approximately 75% open. This provided a minimum of SOpsig water
to the bearing oil coolers .. Subsequent discussions with Fuji have determined that pressure
as high as 60psig (system· design} is acceptable, however flow should be limited to the
maximum design to prevent cavitation in the oil coolers. The pressure control valve has been
manually positioned to act as a fixed orifice to maintain these cooling flows.
Hardware Failures
Two relay interface modules in the electronic governor of Unit 1 failed during initial testing of
the turbine control circuits. The brake solenoid valve failed with the second relay module
failure. It was determined that the relay modules were not rated for the brake solenoid
current or for the motor contactor current in the high pressure oil pump circuit (120Vac).
Interposing relays were provided on both units. and the damaged parts replaced.
During generator short circuit retardation testing on Unit 1, overcurrent relays were damaged.
New parts were provided and the relays repaired.
Also, during generator testing on Unit 1, one of the generator CTs failed. A spare was
installed, and new spare CTs ordered from Fuji.
Spherical Valves
During Preoperational Testing of the spherical valves·, it was noted· that the proof pressure of
the seal water differential switch was below the system pressure. New switches were
obtained from Fuji and installed.
Fire Protection Penstock Supoly
During Pr~operational Testing severe water hammer and valve leakage was noted in the Fire
and Service Water penstock supply system. It was determined that the pressure control
4-12
valves provided by the Contractor were designed for gas service and not suitable for water
•,
) service. This caused the valves to operate extremely fast, causing water hammer and control
fighting between the various valves. The valves were not designed for tight shutoff and thus
caused system pressure to approach penstock pressure when the fire water system was not
in service causing the relief valve to open. Also, the Service Water sump refill line valve was
significantly oversized, causing water hammer in the system when it operated, also causing
the relief valve in the fire water line to open.
The pressure. control valves were replaced with tight shutoff valves designed for water
service. The sump refill valve was replaced with a smaller valve and restricting orifices added
to reduce valve cavitation. the relief valve setpoint was changed to eliminate opening on
operation of the sump refill valve.
The solenoid valves the Contractor provided on the air compressor caused water hammer in
the small Service Water line. Surge suppressors were added at the air compressor skid. This
eliminated the water hammer.
Depression Air System
During full load operation of the units at high tides, it was noted that one depression air fan
could not::depress the discharge chamber level when one unit was operated at full load and
the other at greater than 20MW. During investigations of the turbine efficiency, it was
observed that the air requirement of the turbines is several times more than anticipated by
Fuji. Discharge chamber level is adequately depressed by two fans, the second starts
automatically when the first can not keep up. This is adequate for operation. This problem
will be resolved when the air flow and efficiency problems of the units are resolved.
SCADA System
Several minor hardware problems were found with the SCADA system during testing. All
failed parts were promptly replaced by Landis & Gyr. There are continuing problems
associated with the VHF radio link with the remote RTUs. The delay time allowed by the
system was not sufficient to allow for the time delays of the radio repeaters. Landis & Gyr
has made changes in the software at the master and the RTUs to increase the delay time.
These changes have allowed VHF system to work on a sporadic basis. The present problems
4-13
( appear to be in the VHF and fiber systems. provided by DIVCOM. "there is a frequency conflict
in the VHF system with a user in Anchorage. DIVCOM is investigating to solve these
problems.
Unplanned Load Rejections
Two unplanned complete load rejections and two load rejections to speed-no-load were
experienced.
The first load rejection was due to power system oscillations that developed when Unit 1 was
at full load. The power system stabilizers had not yet been placed in service. It appears that
the oscillations were the result of the unit excitation system interacting with exciters at
Bernice Lake. The power system stabilizers were placed in service, and no further oscillations
of this type were observed.
Unit 2 was inadvertently tripped from full load when the governor was accidently shut off
during a transfer to manual. A protective hood is provided for this control switch and all
operations personnel familiarized with its operation to prevent a recurrence.
The two load rejections to speed-no-load were due to the action of the generator over-
temperature relay. The relay had been wired up without the temperature compensation circuit
in place. This combined with an extremely conservative setpoint for initial testing provided
by Fuji, caused the trips. The circuit has been rewired, and the setpoint revised by Fuji. The
first of these trips caused the deflectors to close completely, rejecting 60MW in 1.5 seconds.
This caused severe transients in the system. The timing of the trip to speed-no-load was
reviewed with Woodward, and the governor changed to slow the load rejection to
approximately 60 seconds.
Generator Efficiency
Generator efficiency was tested on Unit 1 . At all points, the generator meets or exceeds its
efficiency guarantee. Due to the acceptable results, the generator efficiency test was not
repeated on Unit 2.
4-14
/
)
Combined Efficiency
Unit efficiency tests to determine turbine efficiency were performed on both units. The
·turbines are within tolerance at the guaranteed best efficiency point but do not meet their
guaranteed efficiency at full output. See the attached curves. Fuji sent out a special team
to investigate. They theorized that there was too much air being admitted to the turbine by
the depression air system. The results ·of their tests indicate that the amount of air does not
effect efficiency. This issue is still being discussed with Fuji. Fuji has about nine months
(June 3, 1992) to implement a satisfactory resolution.
Governor Needle Sequencing
During needle sequencing, large power swings, as much as 20MW, were observed during the
needle transitions. These were the most severe on the two to three and three to four
transitions. The needle. sequencing method was revised, and the three-needle operating
condition deleted. The loss of efficiency by deleting this operation is slight. After revision,
the power swings were reduced to 1-2MW. Tuning of the CEA Dispatch SCADA system was
done to reduce overshoot and undershoot when under dispatch control.
Water in Turbine Bearings
During Fuji's efficiency retest, water was noted in the turbine bearing oil on both units. The
source of water was traced to condensation in the turbine pits, and leakage past the dowel
pins on the deflector servomotor. Fuji has investigated the water source and designed
remedial measures included sealing the dowel pins, additional ventilation, and a water
detection system. The changes that can be implemented with the units on line have been
completed. The remainder will be implemented at the next outage. The oil for the Unit 2·
bearing has been replaced, and the Unit 1 bearing run through a filter press.
Accidental Tunnel· Dewatering
The power tunnel gates have been provided with a fail safe closing circuit on loss of SCADA
communications. SCADA communications failed late one night in August, and the gates
automatically closed. Both units were running at the time, and the tunnel was dewatered
down to the lower elbow before the units tripped off on reverse power. Due to incomplete
communications circuits to the permanent facilities, the operators were not alarmed at the
4-15
loss of communications. Several alternatives to the loss of communications gate closing
circuit are be evaluated by AEA.
4.4 TURBINE/GENERATOR
Status as of September 30. 1991
All equipment supplied under the Turbine/Generator Contract,
two (2) vertical, six-jet Pelton turbines, with digital governors
two (2) 5-foot diameter spherical valves at the turbine inlets,
two (2) a.c. generators, 63 MVA, 300 rpm, with static excitation,
has been installed and commissioned, and started commercial operation on September 1,
1991. The equipment, except for the governors, was manufactured by Fuji Electric Co., Ltd
of Tokyo, Japan. The governors were manufactured by Woodward Governor Company of
Stevens Point, Wisconsin.
All specified drawings and documentation, except for some governor drawings, have been
submitted in the final form and approved by the Engineer. There are several governor
drawings which need to be revised to reflect field adjustments made during commissioning.
Following receipt of these drawings by Stone & Webster (in early October '91), the entire set
of drawing and document originals will be handed over to the Owner.
The two installed turbine generator units have been operated successfully for more than a
month, generating power within a wide range of power outputs. The units are running
smoothly, exhibiting no objectionable operating phenomena. There are several issues which
need to be resolved before the Final Acceptance can take place and the Contract be closed.
As demonstrated by the field efficiency tests and subsequent performance data
measurements, the turbines do not meet guaranteed efficiency at full power output and 1 , 1 00
feet net head by approximately one percent (Figure 4-1 0). Fuji investigated the problem in
the field and concluded that the reduction of efficiency is partially caused by excessive flow
rate of air admitted to the turbine either by natural aspiration or forced by compressors.
Restriction of air flow rate to improve turbine efficiency may prevent successful water
4-16
\
depression under high tides. The problem is quite complex and a suitable solution is still being
soug~t.
At the end of August 1991 a one-inch layer of water was detected at the bottom of the
turbine guide bearing sump of Unit 2 and traces of water were detected in the turbine guide
bearing oil of Unit 1 . Possible causes were identified as a leaking taper pin on one of the
deflector bushings, water condensation in the head cover air vent, insufficient venting of the
turbine pit, etc. The T-G Contractor was prepared to start with the remedial work
immediately, however, the reservoir is now full and water is being spilled. Any unit shut
down would mean a direct loss of generation. Therefore, the Owner decided to delay this
work until the end of December '91 or early January '92.
4-17
DATE
30-0ct-90
31-0ct-90
O.S-No\·-90
06-Nov-90
07-Nov-90
08-Nov-90
09-Nov-90
10-Nov-90
12-Nov-90
13-Nov-90
14-Nov-90
l.S-Nov-90
115-Nov-90
17-Nov-90
19-Nov-90
20-Nov-90
21-No\·-90
24-Nov-90
26-Nov-90
27-No\'-90
28-Nov-90
29-Nov-90
30-Nov-90
03-Dec-90
04-Dec-90
05-Dec-90
06-Dec-90
07-Dec-90
08-Dec-90
09-Dec-90
11-Dcc-90
12-Dec-90
13-Dec-90
14-Dcc-90
15-Dec-90
16-Dec-90
17-Dec-90
18-Dec-90
19-Dec-90
20-Dec-90
21-Dec-90
27-Dec-90
ELEVATION
(FT)
1072.15
1072.15
1072.30
1072.25
1072.25
1072.25
1072.20
1072.20
1072.25
1072.35
1072.35
1072.40
1072.JS
1072.30
1072.40
1072.40
1072.40
1072.40
1072.40
1072.45
1072.45
1072.45
1072.45
1072.2.5
1072.25
1072.10
1072.10
1072.20
1072.20
1072.20
1072.40
1072.40
1072.40
1072.40
1072 . .50
1072.50
1072.60
1072.60
1072.60
1072.70
1072.70
1073.00
DATE
28-Dec-'l()
29-Dec-90
30-Dec-90
02-Jan-91
03-Jan-91
04-J:an-91
O.S-Jan-91
07-Jan-91
24-Jan-91
08-Feb-91
24-Feb-91
27-Fcb-91
28-Feb-91
01-Mar-91
02-Mar-91
03-Mar-91
04-Mflr-91
O.S-Mar-91
06-M:u-91
07-Mar-91
08-Mar-91
09-Mar-91
10-Mar-91
11-Mar-91
12-Mar-91
13-Mar-91
14-Mar-91
l.S-Mar-91
16-M3r-91
17-Mar-91
18-Mar-91
19-Mar-91
20-Mar-91
21-Mar-91
22-Mar-91
23-Mar-91
24-Mar-91
25-Mar-91
26-M.ar-91
28-Mar-91
02-Apr-91
Ol-Apr-91
TABLE 4-1
BRADLEY LAKE FILLING ELEVATION LEVELS
ELEVATION'
(FT)
1073.10
1073.20
1073.20
1073.20
1073.20
1073.10
1073.10
1073.10
1073.60
1073.81
1074.10
1074.30
1074.40
107UO
1074.~0
1074.50
1074.50
1074.50
1074.60
107UO
1074.60
1074.60
1074.70
1075.60
1074.70
1074.70
1074.80
1074.80
1074.60
1074.80
1074.80
1074.80
1074.80
1074.80
1074.80
1074.80
1074.90
1074.90
1074.90
1075.00
1075.10
1075.10
DATE
04-Apr-91
05-Apr-91
06-Apr-91
07-Apr-91
08-Apr-91
09-Apr-91
10-Apr-91
11-Apr-91
12-Apr-91
13-Apr-91
14-AP'-91
U-Apr-91
16-Apr-91
17-Apr-91
18-Apr-91
19-Apr-91
20-Apr-91
21-Apr-91
22-Apr-91
23-Apr-91
25-Apr-91
26-Apr-91
27-Apr-91
28-Apr-91
29-Apr-91
30-Apr-91
01-May-91
02-May-91
03-May-91
04-May-91
05-May-91
06-May-91
07-May-91
08-May-91
09-May-91
10-May-91
11-May-91
12-May-91
13-May-91
14-May-91
16-May-91
17-May-91
ELEVATION'
(FT)
1075.30
1075.30
1075.30
1075.30
107l.30
1075.30
1075.20
1075.20
1075.20
1075.20
1075.40
107l.30
1075.50
107l.50
107l.50
1075.50
1075.60
1075.60
1075.70
1075.70
1075.70
1075.90
1076.00
1076.10
1076.30
1076.50
1076.60
1076.80
1077.00
1077.30
1077.50
1077.90
1078.40
1079.09
1079.40
1079.59
1079.80
1080.00
1080.19
1080.40
1080.69
1080.90
4-18
DATE
18-Moy-91
19-May-91
20-May-91
21-May-91
22-M•y-91
23-May-91
24-May-91
25-May-91
26-May-91
28-May-91
29-May-91
30-May-91
01-Jun-91
03-Juc-91
04-Jun-91
O.S-Juc-91
06-Jun-91
07-Jun-91
08-Jun-91
10-Juc-91
11-Jun-91
12-Jun-91
13-Jun-91
14-Jun-91
15-Jun-91
16-Jun-91
17-Jun-91
18-Jun-91
26-Jun-91
27-Jun-91
28-Jun-91
29-Jun-91
30-Jun-91
01-Jul-91
02-Jul-91
03-Jul-91
04-lul-91
05-Jul-91
06-Jul-91
07-lul-91
08-Jul-91
09-lul-91
ELEVATION'
(FT)
1081.19
1081.59
1081.90
1082.40
1083.00
"1083.69
1084.40
1085.50
1086.09
1087.69
1088.60
1089.20
1089.80
1091.80
1091.70
1093.10
1093.30
1094.00
1094.30
1095.30
1095.80
1096.30
1097.00
1097.69
1098.50
1099.00
1100.30
1101.00
1113.40
1114.69
111l.80
1116.80
1117.90
1119.00
1120.09
1120.80
1122.19
1123.19
1124.19
1125.09
1126.09
1127.30
DATE
10-lul-91
11-Jul-91
15-lul-91
17-lul-91
26-lul-91
27-Jul-91
29-Jul-91
01-Aug-91
02-Aug-91
03-Au,&-91
04-Au&-91
O.S-Au&-91
06-Aug-91
07-Au&-91
08-Aug-91
09-Aug-91
10-Aug-91
11-Aug-91
12-Aug-91
13-Aug-91
14-Au&-91
15-Au,&-91
16-Aug-91
17-Au&-91
18-Aug-91
19-Aug-91
20-Aug-91
21-Au&-91
22-Aug-91
24-Aug-91
25-Aug-91
26-Aug-91
27-Aug-91
28-Aug-91
29-Aug-91
30-Au&-91
31-Aug-91
01-Sep-91
02-Sep-91
03-Sep-91
04-Sep-91
05-Sep-91
ELEVATION
(FT)
1128.10
!130.l0
1131.90
1134.60
1140.80
1141.20
1142.70
1145.20
1146.50
1147.40
1148.00
1148.60
1149.10
1149.l0
1150.00
1150.40
1150.80
1151.l0
1152.60
1153.60
1155.00
1156.00
1157.10
11.58.10
1159.10
1160.00
1160.50
1161.00
1161.50
1161.90
1162.30
1162.70
1163.00
1163.10
1163.30
1163.40
1163.40
1163.40
1163.40
1163.70
1164.10
1164.70
DATE
06-Sep-91
07-Sep-91
08-Sep-91
09-Sep-91
10-Sep-91
11-Sep-91
12-Sep-91
20-Sep-91
23-Sep-91
25-Sep-91
ELEVATION
(FT)
116l.OO
1165.<0
1166.00
1167.00
1163.20
1169.00
1169.40
1177.85
1178.00
1179 . .50
TABLE 4-2
BRADLEY LAKE IIYDROELECilUC PROJECf
MONUMENT SETfLEMENT I>ATA DAM uPSTREAM FACE
11-0ct-91
SP-IA SP-IB SP-IC
MOVEMENT MOVEMENT MOVEMENT MOVEMENT MOVEMENT MOVEMENT
ELEVATION SINCE LAST FROM INITIAL ELEVATION SINCE LAST FROM1NITIAL ELEVATION SINCE LAST FROM INffiAL
DATil (FT) READING (FTI READING (FTI (FTI READING (FT) READING (FT) (FTI READING (FT) READING (FT)
10-JG-90 1120.156 INITIAL 1120.170 INITIAL 1120.146 INITIAL
05-22-91 1120.147 ~.009 -0.009 1120.158 -0.012 ~-012 1120.130 -0.016 ~.016
06-22-91 1120.143 -0.004 -0.013 1120.156 -0.002 -0.014 1120.129 -0.001 -0.017
06-20-91 1120.125 ~.018 ~.OJ I 1120.133 ~.023 ~.037 1120.106 ~.023 ~.040
06-26-91 1120.146 0.021 ~.010 1120.154 0.021 -0.016 1120.126 0.020 ~.020
07-02-91 (I) (I) (I)
07-15-91 (I) (I) (I)
07-26-91 (I) (I) (II
08-08-91 (II (I) (II
08-27-91 (I) (I) (I)
09-18-91 (I) (I) (I)
SP--ID SP-IE
MOVEMENT MOVEMENT MOVEMENT MOVEMENT
ELEVATION SINCE LAST FROM INITIAL ELEVATION SINCE LAST FROM INITIAL
DATil (FTI READING (FT) READING (FT) (FT) READING (FTI READING (FT)
10-J0-90 1120.133 INITIAL 1120.146 INITIAL
05-22-91 1120.109 -0.024 -0.024 1120.119 ~.027 ~.027
06-22-91 1120.101 -0.008 -0.032 1120.117 -0.002 -0.029
06-20--91 1120.084 -0.017 -0.049 1120.094 -0.023 -O.OSl
06-26-91 1120.104 0.020 -0.029 1120.106 0.012 -0.040
07-02-91 (I) (I)
07-15-91 (II (II
07-26-91 (II (II
08-0R -91 (I) (I)
08-27-91 (I) (I)
09--18-91 (II (I)
(I)-MONUMENT COVERIJ OY WATER
.p.
I
N
0
Page 1 of 2
BRADLEY LAKE IIVDROEl.ECili.IC PROJECI'
MONUMENTSETILEMENTDATA DAM CREST AND SPILLWAY CREST
11-0ct-91
SP-2A SP-28
MOVEMENT MOVEMENT MOVEMENT
EI.EVATION SINCE LAST FROM INITIAL ELEVATION SINCE LAST
DATE (FT) READING (FTI READING (FT) (FTI READING (FTI
10-30-90 1189.974 INITIAL 1189.9.19 INITIAL
0~-22-91 1189.913 -1l.OOI 1189.9~3
06-22-91 1189.974 0.001 0.000 1189.9.14 0.001
06-20-91 1189.969 -0.00.1 1189.948
06-26-91 1189.97~ 0.006 0.001 1189.9~4 0.006
07-02-91 1189.968 -0.007 -0.006 1189.948 -0.006
07-U-91 1189.980 0.012 0.006 1189.9.19 0.011
07-26-91 1189.978 -0.002 0.004 ll89.9.l.l
08-08-91 1189.917 0.003 0.002
08-27-91 1189.97.l -0.002 0.001 ll89.9.l.l -1l.002
09-IB-91 1189.970 -0.00~ 1189.9.l0
SP-2E SP-2F
MOVEMENT MOVEMENT MOVEMENT
ELEVATION SINCE LAST FROM INITIAL ELEVATION SINCE LAST
DATE (FT) READING (FT) READING (FT) (FTI READING (FT)
10-30-90 1189.96.1 INITIAL 1189.973 INrriAL
0~-22-91 1189.9~.1 -0.010 -0.010 1189.960 -0.013
06-22-91 1189.946 -0.009 -0.019 1189.9.ll -0.009
06·20-91 1189.946 0.000 -0.019 1189.950
06-26-91 1189.951 0.005 -0.014 1189.957 0.007
07-2-91 1189.947 -0.004 -0.018 1189.952 -0.005
07-1 ~-91 1189.962 0.01~ -0.003 1189.967 0.01.1
07-26-91 1189.955 -0.0<17 -0.()10 1189.9.l9 -0.008
OR OR -91 1189.955 0.0<10 -0.010 1189.960 0.001
OR· 27-91 1189.95.1 0.000 -O.IHO 1189.959 -O.CKll
0?·18--91 1189.948 -0.007 -0.017 1189.951 ·O.IKlS
TABLE 4-3
SP-2C
MOVEMENT MOVEMENT MOVEMENT
FROM INITIAL El.EVATION SINCE LAST FROM INITIAL
READING (FT) (FT) READING (FT) READING (FTJ
ll89.9.l4 INITIAL
-{).006 ll89.94.l -0.009 -0.009
-O.OO.l 1189.94.l 0.000 -0.009
-0.011 1189.939 -0.006 -0.015
1189.947 0.008 -0.007
-0.011 1189.939 -0.008 -o.ou
0.000 1189.9~4 o.ou 0.000
-0.004 1189.948 -0.006 -0.006
-0.002 1189.948 0.000 -0.006
1189.946 -0.002 -0.008
1189.940 -0.014
SP-2G
MOVEMENT MOVEMENT MOVEMENT
FROM INITIAL ELEVATION SINCE LAST FROM INITIAL
READING (Ff) (FTJ REAI>ING (FTJ READING (fTJ
1189.928 INrriAL
-0.013 1189.92.1 -0.003 -0.003
-0.022 1189.91.1 -0.010 -0.013
-0.023 1189.914 -0.001 -0.014
-0.016 1189.920 0.006 -0.008
-0.021 1189.917 -0.0<)3 -0.011
-O.IMJ6 1189.932 0.015 0.004
-0.014 1189.922 -0.010 -O,(}()(j
-0.1113 1189.922 0.000 -0.(){16
-0.()14 1189.920 -0.1Hl2 -lJ.008
-0.022 1189.914 0.006 0.014
SP-21>
MOVEMENT
EI.EVATION SINCE LAST
(FTJ READING (FTJ
1189.933 INITIAL
1189.925 -0.008
1189.926 0.001
1189.918 -0.008
1189.924 0.006
1189.919 -O.OO.l
1189.931 0.012
1189.926 -0.00~
1189.927 0.001
1189.926 -0.001
1189.920 -0.006
SP-211
MOVEMENT
ELEVATION SINCE LAST
\
(FTJ READING (FTJ
119~.040 INITIAL
119.1.038
119~.035
119~.033
119.1.041
119~.031
119~.048
119.1.010
119~.027
119~.011
119.l.029
-0.002
-0.003
-0.002
0.008
-0.()(16
0.011
-0.018
-0.003
0.1Ml6
-0.0{)4
MOVEMENT
FROM INITIAL
READING (FTJ
-0.008
-0.007
-0.01~
-0.009
-0.014
-0.002
-0.007
-0.006
-0.007
-0.011
MOVEMENT
FROM INITIAL
REA !liNG (FTJ
-0.002
-0.00~
·0.007
0.001
-O.CK"
0.008
-0.010
-0.011
-().(HJ7
0.011
TAB~E 4-3, CONTINUED
Page 2 of 2
BRADLEY LAKE HYDROELECTRIC PROJECf
MONUMENTSETILEMENTDATA DAM AND SPILLWAY CREST
11-0ct-91
SP-21
MOVEMENT MOVEMENT
ELEVATION SINCE LAST FROM INITIAL ELEVATION
DATE (FT) READING (IT) READING (FT) (FT)
10-30-90 119S.002 INITIAL 1180.199
OS-22-91 119S.OOO -11.002 -0.002 1180.169
06-22-91 1194.99S -0.00.'1 -11.007 (I)
06-20-91 1194.996 0.001 -11.006 (I)
06-26-91 119S.002 0.006 0.000 (I)
07-2-91 1194.996 -0.006 -0.006 (I)
07-1.'1-91 119.'1.009 0.013 0.007 (I)
07-26-91 1194.991 -0.018 -11.011 1180.197
08-08-91 1194.990 -11.001 -0.012 1180.198
08-27-91 1194.99S 0.00.'1 -0.007 1180.200
09-IH 91 1194.988 -0.007 -11.014 1180.198
(1)-WEATIIER WOULD NOT AUOW ACCE.~S TO MONUMENT
SP-21
MOVEMENT MOVEMENT
SINCE LAST FROM INfrtAL
READING (FT) READING (FT)
INITIAL
-11.030 -11.030
0.028 -11.002
0.001 -0.001
0.002 0.001
-11.002 -11.001
SP-2K
MOVEMENT MOVEMENT
ELEVATION SINCE LAST FROM INITIAL
(FT) READING (FT) READING (FT)
1180.130 INITIAL
1180.100 -0.030 -11.030
(I)
(I)
(I)
(I)
(I)
1180.122 0.022 -0.008
1180.127 -0.003
1180.13) 0.006 0.003
1180.127 -11.006 -0.003
.J:'
I
N
N
BRADLEY LAKE IIYDROELEClli.IC PROJECT
MONUMENT SETil..EMENT DATA DAM DOWNSTREAM BENCH
11-0d-91
ELEVATION
DATE (FT)
10-30-90 107.5.732
0.5-22-91 107.5.712
06-22-91 107.5.670
06-20-91 107.5.660
06-26-91 107.5.667
07-2-91 107.5.661
07-1.5-91 107.5.66.5
07-26-91 107.5.666
08-08-91 107.5.666
08·27-91 107.5.662
09-18-91 107.5.662
(I)-MONUMENT DESTROYED 6-4-91
(2)-NEW MONUMENT
SP-JA
MOVEMENT MOVEMENT
SINCE LAST FROM INITIAL
READING (FT) READING (FT)
INITIAL
~.020 .-0.020
~.042 -0.062
~.010 -0.012
0.007 -0.06.5
~.006 -0.071
0.004 -o.067
0.001 -0.066
0.000 ~.066
-0.004 -0.070
0.000 ~.070
TABLE 4-4
SP-38
MOVEMENT
ELEVATION SINCE LAST
(FT) READING (FT)
1076.106 INITIAL
1076.099
1076.081
1076.074
1076.086
1076.080
1076.088
1076.088
1076.086
1076.081
1076.084
SP-JC
MOVEMENT MOVEMENT MOVEMENT
FROM INITIAL ELEVATION SINCE LAST FROMINmAL
READING (FT) (FT) READING (Ff) READING (FT)
1076.0.5.5 INITIAL
~.007 -0.007 1076.048 -0.007 ~.007
-0.018 -0.02.5 (I)
~.007 -0.032 107.5.91.5 (2)
0.012 -o.020 107.5.923 0.008 0.008
~.006 -0.026 107.5.910 -0.013 ~.00.5
0.008 -0.018 107.5.920 0.010 0.00.5
0.000 -0.018 107.5.920 0.000 0.00.5
-0.002 -0.020 107.5.917 ~.003 0.002
-0.00.5 -0.02.5 107.5.91.5 -0.002 0.000
0.003 ~.022 107.5.916 0.001 0.001
1 At:JLE 4-5
DRADLEY LAKE
MONUMENT OFFSET DATA DAM UPSTREAM FACE
BASIS OF STATIONS PCM 4
LINE SP-1
11-0d-91
MONUMENT-SP-IA SP-18 SP-IC
DIFFERENCE DIFFERENCE DIFFERENCE DIFFERENCE DIFFERENCE DIFFERENCE
FROM LAST FROM INITIAL FROM LAST FROM INITIAL FROM LAST FROM INITIAL
DATE STATION OFFSET READING (FT) READING (FT) STATION OFFSET READING (FT) READING (FT) STATION OFFSET READING (FT) READING (FT)
10-30-90 4•00.09 113.930 4•99.90 113.900 '•99.H 113.930
0'·22-91 4•00.11 II 3.930 0.000 0.000 4•99.91 113.910 0.010 0.010 '•99.,6 113.930 0.000 0.000
06-,-91 4•00.02 113.940 0.010 0.010 4•99.83 113.920 0.010 0.020 '•99.48 113.930 0.000 0.000
06-20-91 4•00.01 113.9'0 0.010 0.020 4•99.81 113.920 0.000 0.020 '•99.47 113.930 0.000 0.000
06-26-91 4•00.01 113.9,0 0.000 0.020 4•99.83 113.920 0.000 0.020 '•99.48 113.930 0.000 0.000
07-2-91 (I) (I) (I)
07-U-91 (I) (I) (I)
.p-07-26-91 (I) (I) (I)
I
N 08-08-91 (I) (I) (I)
w
08-27-91 (I) (II (I)
09-18-91 (I) (I) (I)
MONUMENT-SP-ID SP-IE
DIFFERENCE DIFFERENCE DIFFERENCE DIFFERENCE
FROM LAST FROM INITIAL FROM LAST FROM INITIAL
DATE STATION OFFSET READING (FT) READING (FT) STATION OFFSET READING (FT) READING (F.f)
10-J0-90 7•00.01 113.940 7•81.04 113.9,0
OS-22-91 7•00.04 113.940 0.000 0.000 7•81.08 113.960 0.010 0.010
06-,-91 6•99.9, 113.940 0.000 0.000 7•80.98 113.9,0 -0.010 0.000
06-20-91 6•99.93 113.940 0.000 0.000 7•80.94 113.9SO 0.000 0.000
06-26-91 6•99.96 113.940 0.000 0.000 7•80.96 113.9SO 0.000 0.000
07-2-91 (I) (I)
07-IS-91 Ill (I)
07-26-91 (I) (I)
08-!18-91 (I) (I)
08 ·27-91 (I) (I)
09-18-91 (I) (I)
(I J-MONUMENT COVERED DY WATER
Page 1 of 2
MONUMENT-
DATE STATION
10-30-90 2•23.93
0~-22-91 2•29.93
06-3-91 2•23.93
06-20-91 2•23.92
06-26-91 2•23.93
07-2-91 2•23.92
07-U-91 2•23.92
07-26-91 2•23.92
08-08-91 2•23.92
08-27-91 2•23.92
09-18-91 2•23.92
MONUMENT-
DATE STATION
10-30-90 5•00.10
0~-22-91 5•00.11
06-5-91 5•00.11
06-20-91 5•00.10
06-26·-91 5•00.10
07-2-91 5•00.10
07-IS-91 5•00.10
07-26-91
08-08-91 5•00.10
011-27-91 5•00.10
09-18-91.
Sf-2A
OFFSET
-o.OIO
0.010
-D.OIO
-0.020
-0.020
-o.020
-o.020
-0.020
-0.020
-o.020
-o.020
SP-20
OFFSET
0.010
0.010
0.000
0.010
0.010
0.020
0.010
0.010
0.020
0.010
0.010
DIFFERENCE
FROM LAST
READING IFO
0.020
-o.020
-0.010
0.000
0.000
0.000
0.000
0.000
0.000
0.000
DIFFERENCE
FROM LAST
READING (FTI
0.000
-0.010
0.010
0.000
0.010
-0.010
0.000
0.010
-0.010
0.000
TABLE 4-6
MONUMENT OFFSET DATA
DAM CREST AND SPILLWAY CREST
DIFFERENCE
FROM INITIJ\L
READING (FT) STATION OFFSET
2•99.80 0.010
0.020 2•99.81 o.oro
0.000 2•99.80 0.010
-0.010 2•99.80 0.010
-o.o1o 2•99.80 0.020
-D.OIO 2•99.79 0.020
-0.010 2•99.80 0.010
-0.010 2•99.80 0.020
-D.OIO 2•99.80 0.020
-0.010 2•99.81 0.010
-o.o1o 2•99.80 0.010
DIFFERENCE
FROM INITIAL
READING (FT) STATION OFFSET
0.040
0.000 3•99.79 0.040
-0.010 3•99.79 0.030
0.000 5•99.78 0.040
0.000 3•99.78 0.040
0.010 5•99.77 0.040
0.000 5•99.77 0.040
0.000 3 •99. 77 O.U40
0.010 5•99.78 0.050
0.000 5•99.78 O.ll40
O.CXIO 5•99.76 O.ll40
SP-28
DIFFERENCE
FROM LAST
READING (FT)
0.000
0.000
0.000
0.010
0.000
-o.OIO
0.010
0.000
-D.OIO
0.000
SP-2E
DIFFERENCE
FROM LAST
READING (Ff)
0.000
-0.010
0.010
0.000
0.000
0.000
0.000
0.010
-0.010
0.000
DIFFERENCE
FROM INITIJ\L
READING (FT) STATION
4•00.00
0.000 4 •00.00
0.000 3•99.99
0.000 3•99.99
0.010 3•99.99
0.010 3•99.99
0.000 3•99.99
0.010 4•00.00
0.010 3•99.99
0.000 4•00.00
0.000 3•99.98
DIFFERENCE
READING (FTI STATION
6•99.29
0.000 6•99.30
-0.010 6•99.30
0.000 6•99.29
0.000 6•99.29
0.000 6•99.28
0.000 6•99.28
0.000 6•99.28
0.010 6•99.29
O.ll!IO 6•99.29
SP-2C
DIFFERENCE DIFFERENCE
FROM LAST FROM INITIAL
OFFSET READING (FT) READING (FT)
0.000
0.000 . 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.010 0.010 0.010
0.000 -0.010 0.000
0.000 0.000 0.000
0.010 0.010 0.010
0.000 -0.010 0.000
0.000 0.000 0.000
SP-2F
DIFFERENCE DIFFERENCE
FROM LAST FROM INITIAl.
OFFSET READING (FT) READING (Ff)
0.030
0.030 0.000 0.0!10
0.020 -0.010 -0.010
0.030 0.010 0.0!10
0.030 0.000 0.000
0.030 0.000 0.000
0.030 0.000 0.0110
0.030 0.000 O.!XIO
0.040 0.010 0.0(0
0.030 -0.010 n.OIJO
0.03() O.OIKJ 0.1100
.p.
I
N
VI
Page 2 of 2
MONUMENT-
DATE
10-J0-90
OS-22-91
06-S-91
06-20-91
06-26-91
07-2-91
07-IS-91
07-26-91
011-011-91
011-27-91
09-18-91
MONUMENT-
DATE
10-J0-90
OS-22-91
06-~-91
06-20-91
06-26-91
07-2-91
07-U-91
07-26-91
08-08-91
08-27-91
09-18-91
STATION
7+99.09
7+99.09
7+99.09
7+99.011
7+99.011
7+99.07
7+99.08
7+99.09
7+99.08
7+99.09
7+99.07
STATION
10+44.62
10•44.61
(II
(I)
(I)
10•44.60
10•44.60
10•44.58
10•44.61
10•44.61
10•44.60
SP-20
OFFSET
-0.040
-().040
-0.060
-().040
-().040
-().040
-0.040
-0.040
-0.0~0
SP-ll
OFFSET
0.000
0.000
0.010
0.000
-0.010
0.010
-0.010
-0.010
(1)·-WE/\TIIER WOULD NOf ALLOW ACOoSS
DIFFERENCE
FROMU.ST
READING (FT)
0.000
-().020
0.020
0.000
0.000
0.000
0.000
0.000
0.000
-().010
DIFFERENCE
FROMU.ST
READING (FT)
0.000
0.000
0.000
0.000
0.010
-0.010
-0.010
0.020
-(),020
0.000
TABLE 4-6 CONTINUED
DIFFERENCE
FROM INITIAL
READING (FT) STATION
9+29.96
0.000 9+29.97
-().020 9+29.96
0.000 9+29.9S
0.000 9+29.9$
0.000 9+29.94
0.000 9+29.96
0.000 9+29.96
0.000 9+29.9S
0.000 9+29.95
-().010 9+29.94
DIFFERENCE
FROM INITIAL
READING (FT) STATION
11+19.96
0.000 11•19.96
0.000
0.000
0.000
(II
(I)
(I)
0.010 11•19.9~
0.000 11•19.95
-0.010 11•19.9~
0.010 11•19.99
-0.010 11•19.97
-0.010 11•19.95
OFFSET
0.000
0.000
-0.010
0.010
0.010
0.010
0.020
0.020
O.OJO
0.010
0.010
OFFSET
0.000
0.000
0.010
0.000
0.000
0.010
-0.010
-0.010
SP-211
DIFFERENCE DIFFERENCE
FROMU.ST FROM INITIAL
READING (FT) READING (fTl STATION
9•93.09
0.000 0.000 9•93.09
-().010 -0.010 9•93.09
0.020 0.010 9+93.10
.0.000 0.010 9•93.09
0.000 0.010 9•93.10
0.010 0.020 9•93.10
0.000 0.020 9+93.09
0.010 0.0]0 9+93.11
-().020 0.010 9+93.12
0.000 0.010 9•93.10
SP-2K
DIFFERENCE DIFFERENCE
FROMU.ST FROM INITIAL
READING (FT) READING (FT)
0.000 0.000
0.000 0.000
0.000 0.000
0.000 0.000
0.010 0.010
-0.010 0.000
0.000 0.0110
0.010 0.010
-0.020 ·0.010
0.000 -0.010
OFFSET
0.000
0.000
0.000
0.000
-0.010
0.000
-().010
-0.010
0.010
-0.010
SP-21
DIFFERENCE
FROMU.ST
READING (FT)
0.000
0.000
0.000
-(J,OIO
0.010
-0.010
0.000
0.020
-(),020
-0.010
DIFFERENCE
FROM INITIAL
READING (FT)
0.000
0.000
0.000
-0.010
0.000
-0.010
-0.010
0.010
-0.010
-0.020
TABLE 4-7
BRADlEY lAKE
MONUMENT OFFSET DATA DAM DOWNSTREAM BENCH
BASIS OF STATIONS PCM 4
LINESP-l
11--oct-91
MONUMENT-SP-lA SP-lB SP-3C
DIFFERENCE DIFFERENCE DIFFERENCE DIFFERENCE DIFFERENCE DIFFERENa;:
.p.
FROM lAST FROM INITIAL FROM LAST FROM INITIAl I FROM LAST FROMINITW.
f\,)
"' DATE STATION OFFSET READING (FTI READING (FT) STATION OFFSET READING (FT) READING (FT) STATION OFFSET READING (FTI READING (FT)
10-l0-90 6•60.01 -202.110 7•20.06 -202.090 7-110.12 -101.170
05-22-91 6•60.04 -202.100 0.010 0.010 7•20.07 -202.090 0.000 0.000 7•80.17 -202.150 0.010 0.020
06-5-91 6•60.03 -202.100 0.000 0.010 7+20.06 -202.080 0.010 0.010 (I)
06-10-91 6•60.02 -202.100 0.000 0.010 7+20.06 -202.100 -0.020 -o.OIO 7•80.3] -202.160 (2)
06-26-91 6•60.01 -202.100 0.000 0.010 7+20.05 -202.090 0.010 0.000 7•80.32 -202.150 0.010 0.020
07-2-91 . 6•60.02 -202.100 0.000 0.010 7•10.06 -202.080 0.010 0.010 7•80.33 -202.150 0.000 0.020
07-15-91 6•60.03 -202.100 0.000 0.010 7•10.06 -202.090 -o.OIO 0.000 7•80.33 -202.160 -6.010 0.010
07-16-91 6•60.0] -202.100 0.000 0.010 7•20.06 -102.090 0.000 0.000 7•80.34 -202.160 0.000 0.010
08-68-91 6•60.0] -102.100 0.000 0.010 7•10.07 -202.090 0.000 0.000 7•80.]6 -202.150 0.010 0.020
08-17-91 6•60.01 -201.100 0.000 0.010 7•20.05 -202.090 0.000 0.000 7•80.]] -202.160 -0.010 0.010
09-18-91 6•60.01 -202.100 0.000 0.010 7•10.06 -102.090 0.000 0.000 7•80.)4 -202.150 0.010 0.020
(I)-MONUMENT DESTROYED
(2)-NEW MONUMENT
\
TABLE 4-8
SPILLWAY SEEPAGE FLOW DATA
DEPTH OF FLOW
OVER WEIR,h FLOW,Q
DATE (FT) (GPM)*
RESERVOIR
LEVEL
EL (ft)
------------------------------------------17-Jul-91
01-Aug-91
02-Aug-91
03-Aug-91
04-Aug-91
05-Aug-91
06-Aug-91
07-Aug-91
08-Aug-91
09-Aug-91
10-Aug-91
11-Aug-91
12-Aug-91
13-Aug-91
14-Aug-91
15-Aug-91
16-Aug-91
17-Aug-91
18-Aug-91
19-Aug-91
20-Aug-91
21-Aug-91
22-Aug-91
24-Aug-91
25-Aug-91
26-Aug-91
27-Aug-91
28-Aug-91
29-Aug-91
30-Aug-91
31-Aug-91
01-Sep-91
02-Sep-91
03-Sep-91
04-Sep-91
05-Sep-91
06-Sep-91
07-Sep-91
08-Sep-91
o9-sep-91
10-Sep-91
11-Sep-91
12-Sep-91
20-Sep-91
0
0.03
0.13
0.14
0.14
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.19
0.19
0.19
0.19
0.19
0.19
0.22
0.22
0.23
0.23
0.23
0.23
0.23
0.23
0.23
0.23
0.23
0.23
0.23
0.23
0.23
0.23
0.23
0.23
0.23
0.23
0.23
0.23
0.23
0.25
0.27
0
0.19
7.09
8.52
8.52
11.87
11.87
11.87
11.87
11.87
11.87
11.87
11.87
18.18
18.18
18.18
18.18
18.18
18.18
26.15
26.15
29.20
29.20
29.20
29.20
29.20
29.20
29.20
29.20
29.20
29.20
29.20
29.20
29.20
29.20
29.20
29.20
29.20
29.20
29.20
29.20
29.20
35.90
43.45
1134.60
1145.20
1146.50
1147.40
1148.00
1148.60
1149.10
1149.50
1150.00
1150.40
1150.80
1151.50
1152.60
1153.60
1155.00
1156.00
1157.10
1158.10
1159.10
1160.00
1160.50
1161.00
1161.50
1161.90
1162.30
1162.70
1163.00
1163.10
1163.30
1163.40
1163.40
1163.40
1163.40
1163.70
1164.10
1164.70
1165.00
1165.40
1166.00
1167.00
1168.20
1169.00
1169.40
1177.85
· * Flow, Q = 1117.5 h 2 •48 (gpm)
4-27
~
I
N
00
TABLE 4-9
DATE 22-MAY-91
REPORT OF FINDINGS
POWER TUNNEL FALLING WATER TEST
BRADLEY LAKE HYDROELECTRIC PROJECT
DATE TIME
05/21/91 18:54:14
05/22/91 06 :54:1 4
ELAPSED
TIME
MINUTES
305.7666
414.2333
NET
HEAD
CHANGE
995.345
937.511
LOSS
RATE
FT/MIN
SHAFT
VOLUME
PER FT.
LOSS
RATE
GAUMIN
DELTA 720 57.834 0.080325 710.4878 57.06993
M1291125
b w w
l.i...
z
0
>---<
b <r: > w
....:I w
~ w
E-<
1 :~no
ll 00
FIGURE 4-1
IW/\I'II1 U\1<,1 IIJI.ll-~tllll,.ll-:1'. 1'1:·1,,111 I
11 .. 1111/\l. 1<1·, ,J I<Vt)ll< Ill I I IIi.
~vlill!l.ltv1L1·11 ~)I_ITll ~11 HI U1\l1\ Ji,i\lv1 111' .. 11'1 :\1·,.1 l/\1·1
Cf,EST OF DAM, ELF_V I I <JO'
WATER [LLVAlliJN /_r
--/'/./
---------------------------------~-------.. --------. ----..... ------------
MIN OPERA fiNG LEVEL, ELEV. I 080'
~ lOOO-r-O-C_T,__N_O_V+-D-E-C-r-J-AN~--FE-B-r-M-A_R_~_A_P_R+-M-A--Y-+-J-U-N~-J-U-L-+-A-U-G-+-S--E-P-r-0-C_T_~_N_O_V+-D-E-_C__J
,.-..._
E-< w w
J:Z.,
'---"
E-< z w :::g
w > 0
::E
0.10
0.05
-0.00
-0.05
G-B-eB-0 SP-1 A
GBBBEJ SP-1 B
6-6-l'r&-IJ. s p -1 c
~~ SP-10
,.._..,_._....., SP-1 E
---. -==::::::::::: ~~~~~~~-----------------------------------~ POSITIVE = HEAVE
NEGATIVE = SETTLEMENT
-0. l 0 ---r-+---1---1-----t----+-----+--1----·1---+ --·----r---t~--1·---
0CT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT f'JOV D[C
1990 199l
f---< w w l 200 --
G-.
z.
FIGURE 4-2
1<1<,[11 I I I /\1 I Ill I 11·.'1" I I I 11<11 I 'I· I 'I[ I
11·1111;\1 1-'1' ,1_1-:V! 111-.: I II 111·1\,
tvl\ 1111 Jlvlf Ill ·;r I Ill. tv11 IH l1i\l;\ l li\1-;l i I-T'. I
cm.s1 or DAM. H.rv JtlJO'
0 ----WATU~ fLEVAliUIJ
>---<
b
~ / > 1100 -·· / ~ --------------------=~~__::.~=-~-~,-~:~~--- ---
w MIN OPfRATII~G [[VEL. [LlV 1080'
0::: w
E-<
~ 1000 --------t 1---1---+---t----t---1---1.,-------1--------1-------------1---------l-----l-------
oc f NOV DEC JAN FEB MAR APR MAY JUN JUL AUC ~~EY OC 1 NOV DEC
() Jl)
b w 0.05 -w
j:.L,
b t5 -0.00 -
~ w > 0
~ -0.05 --
()(;)88{) S P -2A
lJBI3B£1 SP-28
1.'16666. SP-2C
0(j{j~() SP-20
<rlrl'rlrir s p --2 [
H-H-1-Sl'-21
-to+ of'+ .. ~1f I-/l~
••••• rd 1
:
1 1t
i'O':;ITIVl = II[AV[
~HL;AJIVE = SETTLEMENT
lJ I () 1---I -I -. I -------i----. I . . I ---I -------J------~ ------1----
'>I 1 ''' 1'J 1 Jl c ,IAI·I 1 'Ill MAh' Al 1 1·' MAY Jt.m .HIL AUC • .1 11 '1c r t·JOv nr l ·
I ~J!JO lDDI
·------E---< w w 1200
!i...
z
0 .........
E---< <r: > 1100-w
,__:j
w
~ w
b <r: 1000 ~
0.10
b
z -0.00 ILl
~ w > 0
~ -0.05
FIGURE 4-3
1;1-:/\l)[l I [/\I·J. \J'dJI·.'\)f\11~~~-(\1 ' jlJ't,),ljt'\
111111/\l f~l ~;11-~VCl\l~ I ILLillt,
t,Jlul-.!l.IMU-11 '~~l r I LHviU·JI UAI/\ -. "lJJ I W/\ I. lYI_'~ 1
CREST OF SPILLWAY, [LEV. 11('.0'
, ------ -------·---------- ----- --- ------ ------ ---- ------ - ----,.--- - - --- ---- ----- -
__ ./ [1. 1179 50. 25-S[P-91
--WATEr~ ELEVATIOf\J
/ ---------------------------------=---'--------·-----·--.. -------------------.
MIN OPERAfiNG LEVEL, ELEV. 1080'
1----1---+----1---+---1-
0CT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Gee98 SP-21
GBBBEJ SP-2J
666-8-6 S P - 2 K
POSITIVE = HEAVE
NEGATIVE = SETILEMENT
-0. 1 () ---1 t---~· 1----t--·1---1--.,-·-1 I--
OCT f\JOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
1990 1991
FIGURE 4-4
1-~l-'i\l,ill., 11\l<l lll'I.WOIII_r~ll.-1, 1'1·'1,\,ll' I
11'-llll/\l I< l '., [ IN( "l II\ I II I II I ( :
l·v1 Ul Jlii\·H· 1·11 ·:x·l r Ll_ tvl H·l T D/\ I i\ I 1/\lvl Li( 1\IVJ·I' .11,~ l Mvl hi" I I Cll
.----...
E---< w w 1200 --. --------------·--··-·----· --'--·-· ------------------··----·--. u... --·---------------·-------------·--·····-------
--------. CREST OF 0/\M, ELEV 1 190'
z
0
>--<
E---<
~
---WATER ELEVATIOI'l
> 1100-w
,_.] w
0.::: w
E---<
-----------------------------------
_-'/EI 1179 SO. 25-':>F~'-91
MIN OPER/\TING LEVEL. ELEV. 1 080'
~ 1000~-~---~--~-~---~~4---+---~-~--+----~---~----~---+---~
OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
0.10 -.------------------------------------------------------------------------~
E---<
z -0.00 t:il ::;:s
(il
> 0 ::;:s -0.05
G-BBB-0 SP-3A
lrB-BB-EI s p -3 B
~sP-3C
POSITIVE = HEAVE
NEGATIVE = SETTLEMENT
--~---------------
-0. 1 0 -t--+-----·-i 1----t----1----
0CT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEF) OCT NOV DEC
1990 1991
z
0 ..........
FIGURE 4-5
IW/\IJ!I1 lt\11 \I'Jil\·~(illl.'~il:\1 \'\1·1\• I
11·1111;\1 I·: I · .1 IN( .ill·~ I-ll 1.11-11,
tv1<H-JIJiv1\_J,JI li[f';f:l 1)/\l/\-\l/\1\·1 IJJ··.\1·'1;\Jvl 1/\<T
Cf<E.ST OF DAM, ELEV. I 190'
----WATER ELEVA!Iml
b /
;:: 11 00 -____ /'
~ -----------------------------'--~---------------------------------
W MI~J OPERATING LEVEL. ELEV 1 080'
0:: w
b
~ 1000~--~----+---~--~----~--4----+----+---~---~----~---~--~~--+---~
OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
0.10
b t3 -0.00
::;E w > 0
::;E -0.05
G-9-BBO SP-1 A
GBSHEJ SP-1 B
6--l':s-fr-6-6 s p -1 c
**-<> SP-10
frlrlrlt-tr S P - 1 E
----(1~================::>2::~:-----------------------------
POSITIVE = DOWNSTREAM
NEGATIVE = UPSTREAM
-0.10 ---t------l---1 f--------t---l--1-----t----t-------l----t------l----'
OCT NOV DEC JAN FEB MAR APR MAY JUN jUL AUG SEP OCl 1'-JOV DEC
1990 19SJ1
FIGURE 4-6
lWADL [ r LAI< I:_ ll'r'UF~()I-11~ 1_: 11~11 I '1·'1 ),Jl \ I
Jf,llll!\1.. f\[Sff"<VOII\ FILl II II;
~IUhlU~li-_J·JT OFTSF:I" DAIA --J"l;\tvl I_'I,T~·)I
b
G-:1 G-:1 1200 -~--~-~-------------------------------------·--------.--------------------------------------------
[,:... ---------------------- --------------------------------------------------
z
0 ,_...
b
<t; > 1100
G-:1
......::!
G-:1
~
G-:1
b
-<t; 1000 ~
0.10
b
-CReST OF DAM, ELEV. 1190'
--WATER ELEVATIOf'.J
./
r·
____ ./ El 1179 50, 25--SEP--9i
/
MIN OPERATING LEVEL. ELEV. 1 080'
OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
z -0.00-~
~
~ > 0
~
ooeeE> S P-2A
GElE113£1 S P - 2 B
~SP-2C
~~%{) SP-20
~SP-2E
++-H-+ SP-2F ,...,..,..,..>< SP-2G
>~>++-+-* SP-2H
POSITIVE = DOWNSTREAM
NEGATIVE = UPSTREAM
-0. 10 -+---1 t--1---+---t----+~.~--
OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEF' OCf NOV DEC
1990 1991
z
0
>---<
E-<
~ > w
......l w
0:::
t:il
E-<
~
~
,.----...
E-< w
t:il
t:L.
'---"'
E-< z
t:il ::;s
t:il > 0
~
1100-
FIGURE 4-7
hi·'/\[ I[ I I' I AI< [ lit lll~tlll L c II :II. I 'l._'t}. II I I
IIIII I;\[ 1\"ISI:INl lll-2 I II I 11 .. 11.
tvllll·llltvl!l>ll OFf ~~1:: r [l;\IA ',!'Ill W;\·, 11~1 ··,I
--WATER ELEVATIOI'J /_.././
/
---------------------------------.=---~--~-----------------------------
MIN OPERATING LEVEL. ELEV. 1 080'
1000 ~--~I----~---+----+---~---4----+----+----~---~~~--~---4~--+---_J
0.10
0.05
-0.00
-0.05
-0.10-
OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
f----------tl@~@~~ ~ - - - - - -~~~~ --@
<l-~+<H> SP-21
E!mi*BSP-2J
~SP-2K
OCT I'JOV DEC
1990
JAN
POSITIVE = DOWNSTREAM
f\)EGATIVE = UPSTREAM
f----t------1----+--
FEB MAR APR MAY JUN JUL AUG SEFJ OCT NOV DEC
19~)1
FIGURE 4-8
IW•\I1II1 lt\1-1 ll!'l.ll,:ullli __ ll<lt l'l-1•,111.1
111111!\l 1::1 ~~;lf·NUII·~ Ill I ll·lt:
tv1 0 I' ll II vi L I,] I I ) FT:) I r D !\ r !\ I l /\ I·J I II l w I I '_; I I ,: I ;\ lv1 13 L I'. I (~ I I
E--o
~ 1200 ---------------------------·-----------·----------------------·
G-. -------------------
(1,['31 OF DAM, ELEV l 190' __ -~-/ll 1179 50. 25-SEP-'J I
z o --WATER ELEVATIOI'J __.-~ ////_/--
> 1100-~
~ ------------------------------~----------------------------------
w
~ w
b
MIN OPERATING LEVEL. ELEV. 1 080'
;; 1 000 -+---t-----+----t----t----+------i---+-----+--+----1------+-------t------11---
0CT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
0.10
----e
-0.05
GBeB-f) SP-3A
GaB-B-£l SP-3B
~sP-3C
POSITIVE = DOWNSTREAM
NEGATIVE = UPSTREAM
-0. l 0 -+----t +-----\-------\---+----1------f
OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
1990 1991
--------:::E
0..
0
------
~
0
.....::1
J:x_.,
FIGURE 4-9
l::r:~;\llll~l U\1<.1_ lfriWUflLr~ll<lr l 1 [:!l.JJi.l
111111/,1 1-{l_~~XINrJIF\ I ILL!fli~
~~ F'l L LW /W ~:,r~ U 'AC [ F LUW
----------b w w 1200-~-~----------~----------~----~ -~------~-----~--~--------~------~------~-------~---~ --------~-------------
k. CRES f OF SPILLWAY, ELEV_ 1 180' .
.--El 1179.~·0. 25-SEP--91
z / 0 ---WATER ~ELEVATIOt,J /
~ /f
~ 1100 -~ --------------------- ---- ------- -~/_ ------- - - ---~ --.. --- ---~ - - -·_
W MIN OPEf~ATING LEVEL. ELEV. 1 080'
~ w
b
~-1000~---4---+---r--4~-~-~---+---+--~--~---~---r--4~-+---J
OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
lOO.OO
75.00
50.00
25.00
--SEEPAGE WEIR READINGS IN (GPt-(·
Maximum Allowable Seepage
* Spillway Seepage began
when Reservoir Pool
elevation reached
114~
;--I~.IITIAL READING, 17-JUL~9~
0 _ 00 -~-----l-------l-----ii-------l---l---1----+----+------l---~ r--
OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
1990 1991
, ___ ..c
-' z
~
r ._,
::::::
~ c...
>-" . .._; z , .. ,_ -r .._;
~
L:....
~
;-; z -~
\ ~
/ :J .......
FIGURE 4-10
BRADLEY LAKE
HYDROELECTRIC PROJECT
TURBINE EFFICIENCY TEST RESULTS
BEST FULL
EFFCY PT. POWER .
DATE OF TEST: AUGUST 3, 1991 61,110 HP S4,640 HP
92 ~--------~--------~----------~--------~--+1 ------~ I I .
I
9]
GENERATOR POWER OUTPU . MvV
10 20 30 40 50 70
87 ~-----fr-~--~----~~~~----~~~,~~--A~----~~+-----~··~
0 20 40. 60 80 100
TURBINE PO'WER OUTPUT HP'OOO
TURBINE t-.JET HEAD = 1,100 FEET
LEGEND:
GB = 90.7 % ... GUARANTEED EFFICIENCY@ BEST EFFICIENCY POINT
TB = ·90.4 % ... TESTED EFFICIENCY @ BEST EFFICIENCY POINT
GF = 89.8 % ... GUARANTEED EFFICIENCY ((j! FULL POWER
TF = 88.1 Wo .•• TESTED EFFICIENCY @1 FULL POWER
INSTRUMENTATION
,.
/
5.0 INSTRUMENTATION
Settlement and reference monuments have been installed to detect movements of the main
dam and spillway. The data obtained will be used to evaluate the magnitude of structural ·
deflections under hydrostatic, gravitational and seismic loads.
A foundation drainage system has been installed in the spillway with a V-notch weir to
monitor seepage rates.
Six piezometers have been installed in the power tunnel intake portal and at the upper elbow
of the vertical shaft. Four piezometers have been installed on the penstock between the
turbine inlet and the spherical valve. All of these piezometers record pressure in the power
tunnel and penstock automatically.
Four grot.Jndwater piezometers are located along the power tunnel alignment. These
instruments are· used to detect changes in the pre-operational groundwater levels in response
to watering and operation of the power tunnel.
Seismographs installed at the project are monitored by the University of Alaska.
Stream flow is monitored continuously by the SCAD A system in the Bradley River immediately
-·downstream of the dam and at Riffle Reach, at the Middle Fork Diversion, and at the Nuka
River.
The four penstock drains are monitored for flow rates continuously by SCADA.
The frequency of monitoring the above listed instruments is summarized in Table 5-1 a and 5-
1 b. More detailed descriptions of the instruments follow:
5-1
\
\
--------------------------------------------------~----~------------------------------------------------------~----~
.. -:--.. ·' ··.:-~:
/
' I
/
•'¥'
#' -···.
:· ....
/
:' . -: : ....
.. ,.·I
\
• $EI$MOGIIAPH
0 \YOlK POINT
0PEOCSTAL
S BRA$$ CAP
~ AUIMIHUM CAP
• !lOU'
'tDifJICI. I«J sttn.DOT POIWJS
21ann 104
JIQUQ llf
1101114 .~,
110J&)I 012
210JI!I0f:111
lloasl.lt4
.)C2410 114
)WOO,. """"· ...
IVA
IVA
IVA
IVA
"" IVA
10..Q • .J:W ...... ,,.
hD,rt'l
,.,_ ...
0 .011
(-.i.DU
1 .011
1U.tll
1U.f11
I. ALL nrfA TlOMI AJtt: LUrD OW n.tt~U WIU Lr'YII..
oa.lJr'YATIGNI .. UM .U '"CLOUD U>Q,.,-.
4.. ~K.U, U.c::ca.ntll Of" Tlii'AvtJtSD ll4rT 041' DCI!O
RCO'toiO 0.001 ltlOUUto-;xn potAYI Alill ACC~ACT Of"
NTTUI TK.UI1 PAJIT .. ..,,.....
I. TltAvt'Jit'S« CALC\Jl.AllOMS .ANl) AOJV:JTl.lrxTI WIAI WADI
U$1,_. "COIIW.ul .. ~A~ WCOfOO&.
L AU HOfta'Oif'TAL AJIHII..D 'JifiJIII TVIINI:D A WDftWVW 0'
~KT T-..s, W..A.alltt]) AMD IUCOtiiDUl TO n.t MUtiiDT
Jr'COM) M AJtC .I.JC) I«.&Mf:D TO Tl1« IIILUtQT 111l1 0# A
RCOMO 0# AJtC rOft c:..u...c\1\.A note 1"\ntf'OAS..
-J .
····-· _:.-· --·---·-
-~ .--·----~ :-:-~ -~-:-:-: :~:: . ~-~;: •·.··
• MAIN DAM AREA
SURVEY IY10NUMENTATION
J..
0
-...-... .li &:= 15800-FY-321A-1 ~· ~~~~~-----------------;! --... ---..tGOlE/........a-w 5. HOJ5(R
---•H..~ ..,..,...Q..AJRtCH
FIGURE 5-1
j
/
TABLE 5-1a
FREQUENCY OF MEASUREMENT/INSPECTION
AFTER POWER TUNNEL DEWATERING AND DURING NORMAL OPERATION
INSTRUMENT /OBJECT
Power Tunnel Survey Monumentation
Power Tunnel Groundwater Piezometers
Reservoir Level Piezometers
Tunnel Water Level
Penstock Drain Flowmeters
Penstock Piezometers
Manifold Closure Head
(visual inspection for leakage)
Terrain covering tunnel (visual inspection
for unusual drainage)
LEGEND: N/R ..... Not Required
N/A ....• Not Available
AFTER DEWATERING
NOTE 4
Weekly
N/A
N/R
Daily
N/R
N/R
N/R
NOTE 1: Take Readings when monuments are set in place
NOTE 2: Contractor to monitor reservoir level daily
NOTE 3: Will be monitored continuously be SCADA
NORMAL OPERATION
NOTE 4
Annually NOTE 5
NOTE 3
N/R
Weekly
NOTE 3
Weekly
Annually
NOTE 4: As required. Survey performed only if liner shows signs of distress.
NOTE 5: For three years or until readings stabilize
5-2
TABLE 5-1 b
FREQUENCY OF MEASUREMENTS/INSPECTION
DURING FILLING AND NORMAL OPERATION OF RESERVOIR
Instrument
Reservoir Level
Dam and Spillway Surface Settlement
Spillway Drainage Weir
Bradley River Flow
Gage, Downstream of Dam
Bradley River Flow
Gage, Riffle Reach
Middle Fork Diversion
Flow
Nuka River Flow
Power Tunnel High
Pressure ·Gate Leakage
Visual Inspection
Seismic Activity
NOTES:
During Filling
Once per day
Every 1 0 ft of
Reservoir Rise
Every 7 Days
Every 7 Days
Every 7 days
****
****
As Required by
Specifications
Once per day
Continuously,
(Univ. of Ala~ka)
Normal Operation
Continuously (SCADA)
Twice Yearly *
(Spring/Fall)
Monthly **
Continuously (SCADA)
Continuously (SCADA)
Continuously (SCADA)
Continuously (SCADA)
During Routine Inspection
of Operational Readiness
of Equipment
Monthly * *
,,/
Continuously (University
of Alaska)
* For 2 years or until trends are established; thereafter, read on a yearly basis.
** When access to the site is available.
I
*** Continuously if SCADA is operational, every 7 days if manual reading is required.
Manual readings, if required, will be done by U.S.G.S. or Alaska Energy Authority.
5-3
. __ .....
5.1 MAIN DAM AREA
5.1.1 Main Dam and Spillway Settlement
Surface settlement monuments and reference monuments are provided to monitor settlement
and horizontal movement of the crest, upstream face slab and downstream embankment of . .
the dam and the crest of the spillway (Figure 5-1).
Settlement measurements when combined with the reservoir pool level readings, provide basic
performance data on the response of the dam, upstream face slab and spillway.
Nineteen settlement monuments are located along these features; five on the upstream face
slab, seven on the crest and three on the downstream embankment of the dam, three on the
spillway structure and Of"!e on the leveled rock knob situated between the dam and the
spillway.
Seven instrument pedestals are located at the ends of the three lines of the settlement
monitoring points (baseline monuments) and at primary control monuments located within line-
of-sight of the ends of the lines of settlement monitoring points.
The four primary control monuments located at the dam site are used as a control system to
verify the accuracy of the survey instrument before each set of settlement measurements is
made and to reestablish an instrument pedestal or settlement monument if disturbed. The
accuracy of the measurements made at the settl_ement monument locations will be to Second
Order, Class 1 requirements.
Settlement mea~urements are to be made twice per year (spring and fall) until patterns are
established: Thereafter measurements are to be made once per year in the spring or early
summer after breakup. Additionally a survey of the dam site should be completed after every
earthquake that results' in a peak ground acceleration in excess of 0.2g at the project. These
data are available from the University of Alaska, Fairbanks. Additionally, an investigation of
dam settlement should be made if the rate of settlement routinely recorded suddenly
increases.
5-4
5.1.2 Main Dam and Spillway Seepage
The seepage from the spillway foundation curtain passes through a collection system and over
a V-notch weir system (Figure 5-2).
Measurement of flow over the weir is by measurement of the upstream weir-pool level above
the bottom of the V-notch and using the following formula:
Q = 2.49 h2.48
where: 0 = flow over the weir (cfs)
h = height of the weir
pool level above
bottom of the ,v-notch (feet)
Main dam leakage is estimated by deducting fishwater bypass flow, measured by the
fishwater bypass system, al")d spillway seepage from the total Bradley River flow measured
at the United States Geological Survey (U.S.G.S.) stream flow gage station located
immediately downstream of the dam.
I
5.2 POWER TUNNEL AND PENSTOCKS
Four active and four spare (redundant) piezometers are located at the power tunnel intake
portal. Two piezometers monitor reservoir level and two monitor pressure differential across
the intake trash racks. Two piezometers are connected at the upper elbow of the vertical
shaft. All piezometers are routed to the gatehouse. These instruments are capable of
remotely measuring water pressure equal to reservoir pool elevation beginning at El 1 070 feet.
Signals from these instruments are sent to SCADA during normal operation.
Four piezometers are provided between the turbine inlet and the spherical valve on the 5-ft
diameter dismantling section in the powerhouse. The taps are evenly spaced around the
periphery and connected to a ring header. The pi~zometer transducers are read automatically
by the SCADAsystem during normal operation. In addition, two piezometer ~aps are located
on the penstock upstream of the spherical valve and one tap downstream of the spherical
5-5
valve. One upstream tap provides seal Water to operate the spherical valve maintenance seal
and a pressure tap piped to the spherical valve control cabinet. The remaining two taps are
used to measure differential pressure across the spherical valve.
Four groundwater piezometers are located along the tunnel alignment. Each piezometer was
originally equipped with a slotted pipe and a pneumatic piezometer. Not all of the pneumatic
piezometers remain functional. These piezometers were installed during site exploration and
are intended to be monitored annually until readings stabilize. A summary of piezometer
readings to date are given in Table 5-2.
5.3 SEISMIC MONITORING
A seismograph provided at the site is linked to the University of Alaska at Fairbanks,
Geophysical Institute via a telephone line at the microwave tower. Interpretation of the data
will be done by the University staff. There is no provision for reading of the instrumentation
or for collection of data at the project.
5.4 STREAM FLOW MONITORING
USGS stati.ons are located at the mouth of the Bradley River {Riffle Reach) and just below the
dam. Stream flow data is collected by the SCADA system from those stations. Stream flows
are also remotely monitored at the Middle Fork Diversion and at Nuka River downstream of
the Nuka Glacier Pool.
5-6
;
' -----
TABLE 5-2 pg. 1 of 2
Pi~"t-~~-~t~v-No., \aJt: l"',t"llu{ Rtn-23 ' 8/SG, . RYYJ-21, '/65"" Rm-zz, sJec. R'Wl~J':)' lb/B~
loCA.~iDn Wi~~i"' Sletl Li~ 5edi.on R~ll h'\Doj ~ Ftt.«.lf mu;"""'w-Covu Br~lu, 'Riv-e,. F ........ H
Co.-.. Ufe>Y\111(.;~ T~"'"e-J Si4.iio)'\ 24+10 ,~._00 b':l-t-00 llO+OC> 1'11 .. 50 ~0 tiS"t50
T IVI'\l-1 s, .. ; ... ~Ji"'(. el. <r•) 58 llt 132 211 Zs-1'. -lo 2'-6
~el..lc -c..ll'lr -e.l. (ft) s~n.s 1211.4 I ,D 1.1-IS"<J~.o
-f.,~.l 1(."~~ lH) "~0 '"-'5' iOR.5 IIO<J.'-
-bo-Ho..., t.l. (~J -r.2.1· -4 59.G, I ~pltJ,I ett:..3
-""'!lie ~ ve ... 1i~1 0" ve-rtice..l). 39• (A»t.rA1~) 18·( ... ~~) 1.3• (a.v•,.~e)
P;cf#mei•r -l'JfC. · sl~ ... .,(r:r~ "'"'~"" ... tic. -$~~"',t,:pe pn~~ic. ,Jl\~fift. sJa ... Jrite f f"'e~-.. ~··c.-
-St.t\51'-f 1i .Stii'UM el. (fl) . 1~5'-,.., S' IS"Z.a 88S"-818 .513,C. ''33-1(131 IZS0-1~?1 -1~18.5"
-fe.,.vio~~.s i"'~ef"V.J el. ~~ Hc:J-130 fb(,3-8'" ,,, -.. 8, 1(, 31 -//, 2' !3l~ -!fJ~I}
- , ... ~ .. .t el ..... ~eve ti•'· 5"971.3 ll.IS"-IJ.&S IHS"-1115 l~z.z IS""O-15"45"
b(t.~t. T 14)'1ne.l }lt.A.el;"-15-fJ;Ill\ Ph 'f"ea... -1 i c. 5u. .. ~a..c.~ Eleva. -f; on. (H)
ID/I/e5" ---~ ---1529 . .3 ---
-------· ---------
J0/31/«~ --llcH:""' I090.'f -1517.5 15"32.~
--. ----1------f-'-----
B/15}~ '310.~ --------
-------. -·-
B/t"/Bb 3"{,,5" --------
--------.. - -
'J/l3/8f.. ~~2.1 31~.4 II OD. 2. 1~11.4 1128.8 15"2~).5" 1531.9 -. ' ---------·----· --
-,/,/B' M3+-lB (291.8 -I DSS: 2 -I"H.0.1 -I 5" 31.3 --
. ------_,, -·
"/F1/B'3 III-I-53 < 145:0 (ct.-.,) ----,~,2.l , 5'3i. 2. -----·-----------
,/23/S'J 118+4" ... -II --1044.1 -11(.2.0 --
---. ----· ----"fole'J IU.t f-0 ,, II <. l.fS (.,(.,) /fJ3 fl5" ~33.1 11$S.' 15"33.0 ISi3.9 -------------------
7 8/e!J 13Dft,S ----1031.0 !'24.4 1'142.2. }.5"3 1.9
---~
1/15/B, I~C)MZ ----/021.3 --i13is·----
1/lZJ~ I-144-1S ----/012.4 ;D5",, nzo.p 1533.4 1531~0 -
"J/28/B~} IS"I+DI 4( 115" (ct.-,_) --1005.2 B9~.0 I 1-lf>.t IS3_1.3 15"37.0 -'
sjs-18~ 1>1+33 ---9''·1 88,,8 "''·~ IS3t..f ls-i3.~
8 IZ/8' 1(,4,.04 < JH (a,,) ~BIJ.fo 88S.2. ,,8,,'} 1532,2. /530.1
8/t(,/8' J(Z,.Ol_ --~18;8 B18.~ ''as.o 15"2.~~ 153 2-i
9/15/S'J 17l+SO(~-,_Idd., ~ <11S(ct·~) 910.3 811.0 14ll~ /~33.8 1~43, 9 v...-4'.ul SM
~l3o/8~ h~;"' "eJ;f41 s4ft <. /4 S'{J~~) --~18.3 ggz.t, ,,91, -
IO/ ~ }S'J 1'60 _,_ 23 ---~8'0.1 (85}.2) '"81.1 IS21.0 IS"3B.Z
':Jrt.f .,, v~ .. h~J s\to.fl-c,..,t.JJ. t&. .. h -___,-~'?2.."3 ---'''7-' Is I". ' IS'lS. 5
5 1-z./90 (....,vcJ~ Lo:..V ,of 14 "7. 1J -.,tto. o 'iiS.~ < IC.3tz.(d .. y) 151Z. 'f /S2J.I
TABLE 5-2 pg. 2 of 2
Pi~"l.a""'e.te..-No., \a.le 1",-l"lbt Rm-z3 , s/s~ Rm-21, <J/65"" Rn1-ZZ, s}a' RM-1~, ttJ/e5'"
lo~~ian Wi~~;~ Sleel Li~ !ledi tH'\ a ... n mM,~ F4A41f mti;'l't11AW' Covu Br~le., ~i V~'f' F"A.14-\t
~ ... -~,rY',t:"" T"-"'""' ~ .... ;lion 21+10 '{.+00 '-'l~oo llD-t-0() 1 .. 1 ... 50 ~t> .. fiS"tSO
T 14-""~1 s.,~i .. "' l; .. c. el. (fJ) 58 ll1 13l 211 ZS"'f.. -lo 2.'-0
P-el.•le ~ c.. II,,... ~1. (ft) . s~n.s 1211.4 ,,01.1 '5",(-,0
-t,~AI If-"''"' {ft) ""0 ,.,5' . iOB.5 ~~~~:"
-bo-lltltt-l t.l. (#J -f.2.1 -18~.~ /t,Z'J,I a'"·., -""-le 1-r.-V81'~iCA.I 00 ve.,.tic-.1) 38• (AMt.orA1e) 1t•(~e) ·u• . ~ -.v•"'"U)
P;q,w'f.r -_J.,pr. .... _ ____ ___ _ __ .. _51 .. ..-.f,~te. P"K~~~ofic.__ -~~:~ ... .pn~i.c.. __ ,!~~r!tt.... . .!-l4~.fritc_ _,,.,.__~-.-:J •'c.
~---~--"'~.uo:•-d.,!i~r/~!i"c/~1L_ . ·~ JSZ,8_ -~ .88S::8~8 . __ § 13.(. ---.. !~33 :-: 16~ L _ _ ~z-~o-_•-~L..__H'le.s.:-.
_______ :_ f~..,.Vlt'ILS il\~ef'Val tl _ . tl-, ~ ~30 11(,3-6"' "' --18, u~ H-It, 2' ....... ____ !1Zi-:-_ID~~--. ___
-!\"•-.t eL -.\.eve,: .. ,, 5"91.:!. IUS"-I IC.S" 111S'-Ii1S "zz-· .. rs-"o-15'-45"
ba:le._ _ T,."nel 8~;-.t\>tSfJ;,. ~ Ct1~u-._f~ Li~ ~1 Ph~a:f i c. .5u.1' ~a.;c~ E ·~VII. .f.i Ct'\ (f .. ) . ·-...
{,/t/9o l't{.. 3 -C) 52 .... -· I G. S' 't. 4 I 5o'·" -
~~lis/ ,a PJ~ Nf!-9'5'i .0 1r'J<i',3 IC..7€..4 tso'l..? \S'I~.-z..
1.11~1 < l45'{c:V"') NR '3~1.~ 1-79.0 lie. 30. 5" 15oo .I 1'5'1(..'2..
f_~ II -I>Jrt /IQ~.t. 77'i.o ,,.,7., ·I soc~ JJ/,_;l.
-'/' I -'J.IQ 110'-~ 'iiB .3 11"57-':t 14ti'e. 7 /So-:1..4
•/l/'1r ~a. -----
~/,q/cu lit?~ Nit -'d'i:1. l --15-:J:J R
-·
.. -------"
------·····
-------------
'
--·---
-----------------
----. -~
--------------------· ------~------·------.. -------------·--~---
------·--------------
----
Weir Poo I
Leve I
Q = 2.49 h2.48
Weir
where: Q = flow over the weir (cfs)
h = height of the weir
pool level above
bottom of the v-notch (ft)
Bot toM
of
U-No tch
Su~
SPILLWAY WEIR DIAGRAM
(NOT TO SCALE)
FIGURE 5·2
Hole
Drain
REFERENCES
6.0 REFERENCES
Tsunami Hazard to the Facilities of Bradley Lake Hydroelectric Project, Stone & Webster
Engineering Corporation, September 1987
Investigation of Landslide-Induced Wave in Bradley Lake, Bradley Lake Hydroelectric Project,
Stone & Webster Engineering Corporation, December 1987
Report on the Bradley Lake Hydroelectric Project Design Earthquake Study, Woodward-Clyde
Consultants, 1981
Design of Gravity Dams, U.S. Dept. of Interior, Bureau of Reclamation, 1976
Bradley Lake Hydroelectric Project Main Dam and Spillway Grout Curtain Final Construction
Report, Bechtel Corporation, May 1991
Bradley Lake Hydroelectric Project Final Construction Geology Report, Bechtel Corporation,
May 1991
Geotechnical Interpretive Report, General Civil Construction Contract Volume 6, Stone &
Webster Engineering Corporation, June 1987
High Pressure Compaction Grouting, Lower Power Tunnel, Stone & Webster Engineering
Corporation, 1991
Final Supporting Design Report, Powerhouse Construction Contract, Middle Fork ahd Nuka
' Diversions and Reservoir Clearing Contract, Bradley Lake Hydroelectric Project, Stone &
Webster Engineering Corporation, July 1988
Final Supporting Design Report;. General Civil Construction Contract, Bradley Lake
Hydroelectric Project, Stone & Webster Engineering Corporation, March 1988
6-1
Bradley Lake Hydroelectric Project Plant Operation and Maintenance Manual, Stone & Webster
Engineering Corporation, 1991
Bradley Lake Hydroelectric Project, General Design Memorandum No. 2, U.S. Army Corps of
Engineers, February 1982
Bradley Lake Hydroelectric Project, General Design Memorandum No. 1, U.S. Army Corps of
Engineers, June 1981
1Oth and Final Reservoir Filling Report, Bradley Lake Hydroelectric Project, Stone & Webster
Engineering Corporation, October 1991
Study of Probable Maximum Precipitation for Bradley Lake Basin, Alaska, National Weather
Service, May 1961
6-2
STONE & WEBSTER ENGINEERING CORPORATION
76n EAST BERRY AVENUE
ENGLEWOOD, COLORADO 80111-2137
.· REcORD COPY
. FILE NO
.. 'f'R.E .. \.-.S; ')--ADDRESS All CORRESPOND~NCE 1:0 P.O, BOX 5406, DENVER; COLORADO s0217-5406
W.U. lWX: 910 93>0105
W.U. TELEX:~~
TEL£PHONE: 303 741-nOO
RCA TELEX: 289251
FAX: 303-741-7670
303-741-7671
Arif1 Jo ·~ ~ ·. 'l-
BOSTON. MA
CHATTANOOGA:. TN
CHERRY HILL. N.J.
CHICAGO.IL
DALLAS. TX
DECATUR~AL
DENVER. CO
FT. LAUDERDALE. FL
HOUSTON, TX
Mr. D. R. Eberle
Project Manager
Alaska Energy Authority
701 East Tudor Rd.
Anchornge,AK 99503
COMPLETION DESfGN REPORT
BRADLEY LAKE HYDROELECTRIC P-ROJECT
HEW YORK; NY
~~:T~::: ~~ ,;./
PORTLAND~ OR
· RICHLAND. WA
RICHMOND. VA·
PLEASANTON. CA.
· TAMPA."FL
WASH)NGTON. D.C.
January to, 1992
J.O. No. 15800.55
WP'25A
SWEC/AEA/2811
Please find attached five (5) copies of the ·completion 'oesi.9n Report for the Bradley Lake
Hydroelectric Project. This report has been ·revised based on cominents received from the
FERC Boar~f of Consultants since the Fifteenth Me'eting of the Board.
Copies of the report have been distributed to Mr. R. Corso and Mr. A~ Martin of FERC, the
members of the FERC Board of Consultants and 'to Bechtel.
Should you have any questions; 'please call me at (303) 741:-7237.
t -; o~~~·,rsPONDENCE DISTRIBUTiON l
I ------;.·:::.:·:;·;~~·· "'()PIES·
Theodore Criti!<qs
Project Manager
TC/DMJ/swg
Attachments
cc: E. H. Elwin, Bechtel w/enc.
000664.wpf/Bl004
i .r··\:._,!~U~... ·~· • I . ~IL-.!:. t-Jo «-~ wj "._"!--.~~K.uAf..,
;_,~ ...............
(-·---
t
! -··--·-·
.. -R·EbE 1 v e·o
JAI~ 1 3 1992
AlASKA ENERGY AUTHORITY
!SNY • STOi\E ,\. WEI3STER · ''""
. \
J