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SUSITNA· HYDROE-LECTRIC PROJECT
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ALASKA POWER AUTHORITY
SUSITNA HYDROELECTRIC PROJECT
EXTERNAL REVIEW BOARD
MEETING #3
REPORT
OCTOBER 6 -8) 1981
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ALASKA POWER AUTHORITY
SUSITNA HYDROELECTRIC PROJECT
External Review Board Meeting No. #3
MINUTES OF MEETING HELD ON
October 6 -8, 1981, AT OFFICES OF
ACRES AMERICAN INCORPORATED, BUFFALO, NEW YORK
TABLE OF CONTENTS
Agenda
List of Attendees
Report of Meeting
APPENDIX A -Supporting Documentation
APPENDIX B -Report of External Review Board
October 30, 1981
P5700.13
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AGENUA
OCTOBER 6 -Moderator: De Wozniak
08:30 -Introductory .remarks -E. Yould
08:45 -Meeting objectives and study status -J. Lawrence
09:15 -Report on seismic studies -J. Lovegreen
10:15 -Coffee
10:30 -Discussion
11:30 -Report on geotechnical field program -J. Gill
12:00 -Lunch (brought in)
13:00 -Geotechnical interpretation: Watana -S. Thompson
(Geology, borrow area investigations, bed rock conditions, underground
struct~res, relict channel investigations)
13:45 -Discussion
14:15 -Geotechnical interpretation: Devil Canyon -S. Thompson
{Geology, borrow area investigation, bedrock conditions, underground
structures)
15:00 -Coffee
15:15 -Discussion
15:45 -Earthfill dams -D. W. Lamb
(Embankment/cofferdam designs, construction materials, foundation
treatment, relict channel treatment)
16:45 -Discussion
17:15 -Adjourn
18:30 Dinner -courtesy of Acres (M&T Plaza Suite, Jim Gill to organize 11 how
to get there" from the Hilton)
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AGENDA (Cont 1 d)
OCTOBER 7 -Moderator: J. Gill
08:30 -Introductory remarks -J. Lawrence
08:45 -Report on hydrologic field program -J. Hayden
09:15 -Report on hydraulic studies-J. Hayden
(Power I energy estimates, flood estimates) .
10:00 -Coffee
10:15-Report on hydraulic studies (cont'd) -J. Hayden .
(Reservoir level optimization, sedimentatio~ studies)
11:15 -Discussi~n
12:00 -Lunch (brought in)
13:00 -Watana spillway studies -J. Hayden
13:45 -Watana layout studies ~ J. Lawrence
14:30 -Discussion
15:00 -Coffee
.15:15 -Watana/Devi 1 Canyon diversion/low level
15:45 -Wat an a/Dev i 1 Can.yon power developnents -
16:15 -Discussion
17:15 -Adjourn
outlets -R.
J. Hayden
Ibbotson
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AGENDA (Cant ' d)
OCTOBER 7 -Moderato~: J. Gill
08:30 -Introductory remarks -J. Lawrence
08:45 -Report on hydrologic field program -J. Hayden
09:15 -Report on hydraul ir studies -J. · Hayden
(Power/energy estimates, flood estimates)
10:00 Coffee
10! 15 -Report on hydraulic studies (cant' d) -J. Hayden .
(Reservoir leve'l optimization, sedimentation studies)
11:15 -Discussion
12:00 -Lunch (brought in)
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13:00 -Watana spillway studies -J. Hayden
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13:45 -Watana 1 ayout studies -J. Lawrence
14:30 -Discussion
15: 00 -Coffee
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15:15 -Watana/Devil Canyun diversion/low level outlets -R. Ibbotson
15:45 -Watana/Devil Canyon power developnents -J. Hayden
16:15 -Discussion
17:15 -Adjourn
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AGENDA (Cont'd)
OCTOBER 8 -Moderator: D. Wozniak
08:30 -Introductory remarks -J. Lawrence
08:45 -Devil Canyon dam design -R. Ibbotson
09:30 ·Discussion
10:00 -Coffee
10:15 -Devil Canyon spillway studies -J. Hayden
10:45 -Devil Canyon layout studies -J. Lawrence
11:30 -Discussion
12:00 -Lunch (as required)
Afternoon for panel to prepare report
n 16:30 -Closing statements: E. Yould/panel
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LIST OF ATTENDEES __ . ._ ____ _
A'laska Power Authority
E .. P. Yould -· Executive Director
R. A. Mohn -Director ·of Engineering
D. D. Wozniak -Project Manager
APA External Review Panel
M. Copen
Dr. J. Dotma
Dro A. Merritt
Dr. H. Seed
Acres External Panel Members
Dr. A. Hendron
Dr. L. Sykes
Acres
'E. Ei chenbatJTl )
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Dr. D. H. MacDonald ) Internal Review Panel
J. G. S. Thomson )
J. D. Lawrence
Dr. J. W. Hayden
J. D. Gi 11
S. N. Thompson
D. W. Lamb
V. Singh
R. K. Ibbotson
)
)
)
) Participants
)
)
)
M. F. Dumont/D. Peck -Recorders
D. C. Wi 11 ett
M. R. Vanderburgh
G. Krishnan
K. Young
)
)
) Observers
)
Woodward-Clyde Consultants
J. Lovegreen
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ALASKA POWER AUTHORITY
SUSITNA HYDROELECTRIC PROJECT
Extert:1al R'l!view Soard Meeting No. #3
MINUTES OF MEETING HELD ON
October 6 ~ 8, 1981, BUFFALO, NEW VORK .
REPORT OF MEETING
P5700.13
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October 6, 1981
General
Dr. Seed and Dr. Hendron were delayed. J. Lawrence proposed that the Agenda be
adjusted accordingly; Geotechnical Field Program and Geotechnical Interpretation
brought forward, and Seismic Studies Report postponed until later this morning.
1. Introductory Remarks (E. Yould; Executive Director, APA)
-Would be primarily a technical session~
-APA board has been reconstituted.
-CH:her studies are in hand to assess the viable alternatives to Susitna:
(i) Tidal power at Cook Inlet-s~udies by Acres.
(ii) Chakachamna -studies by Bechtel.
( ;: i i) Battel1 e/Ebasco -energy requirements and demand growth studies in
the Rai 1 be 1 t are a.
(iv) Long-term planning of potential industrial expansion in the
state.
-Al.f results of the studies will be available to the legislature by April
1982 for a final decision on FERC application.
-$5 bill ion commitment for state development has already been approved
undel"' the 11 Energy Program for Alaska 11 legislation.
-At the federal level, negotiation is underway to accelerate the FERC
licensing procedure for the Susitna application.
2. Meeting Objectives and Study Status (J. D. Lawrence)
-five major objectives:
2.1 Status of Study
-Power Studies
-Camp/ access
( i )
( i i)
(iii)
( iv)
(v)
Status report
Review field studies
Review proposed layouts
Address previous Board comments
Study completion requirements
Acres study is complete; results of Battelle
forecasts will be incorporated in the
Feasibility Report.
Survey and report completed. Meeting with APA
later this month to consider the recommended
access route.
-Environmental
-Transmission
-Cost Estimates
-Licensing
-Marketing/Finance/
Risk
-Public Participa-
tion
2.2 Field Studies
2.3 Proposed Layouts
2.4 Previous Board Comments:
Studies continue -to be discussed with APA on
Friday, October 9*
Corridor Selection Report has been issued.
To be issued to Ebasco for independent assess-
ment.
Will be filed 1n accordance with new Regula-
t·i ons.
This work has been on hold. ro· be discussed
with APA next week (12-16 October).
PPO work continues, monthly news letters.
To be detailed at this meeting.
To be detailed at this meeting.
-10 comments were listed. These will be dealt with during the course
of this meeting.
2.5 Completion Requirements
-Cost estimates will be given to Battelle by end October 1981.
-Preliminary costs for preferred developments will be available to
Ebasco by end of October (Devil Canyon), November (Watana).
-Geotechnical Report (1981 Studies) by February 1982.
-Feasibility Report
-License Documents
First Draft by 15 Fe~ruary 1982.
Final Draft by 15 March 1982.
By May 1982.
3. Geotechnical Field Work (J. Gill)
3.1 Watana
-Previous investigations were summarized, (USBR & Corps of Engineers,
1950-1978,); a total of 28 boreholes, 18 auger holes and 27 test
pits, plus extensive seismic refraction survey (in excess of 70,000
1 i near feet).
-Acres 1980 investigations: 3 boreholes and 21 auger holes. Seismic
survey extended in the darn abutments and the relict channel area.
Also in the river alluvium to assess its depth (60 to 70 feet near
the dam axis).
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4.
-Acres 1981 investigations: 4 boreholes and 18 auger holes, plus 21
test pits to assess the material available from the borrow areas.
Two of the boreholes (BH3 and BH4) were drilled at the powerhouse
location on the north abutment. Seismic refraction survey extended
farther (38,200 feet).
-Relatively deep permafrost in the south abutment (170 .feet in BH8).
Also in the low-lying area to the southo
3.2 Devil Canyon
-Previous invest·igations were summarized: 22 boreholes, 19 trenches
and test pits, 1,300 linear feet seismic lines.
-Acres 1980 and 1981 investigations: 7 boreholes, 8 auger holes, 6
test pits, 1,600 linear feet seismic refraction lines.
-1980 -BH1 and ~H2 on the north abutment, and BH4 drilled across the
pond areas to locate the suspected shear zone; not found.
-1981 -BH7 did locate the pond shear feature; BH3 drilled through
open shear features; two further holes at the river and the north
abutment.
Geotechnical Interpretation (S. Thompson)
4.1 Watana
-Fins structure is not a single feature, hut a series of ribbed· shear
zones. The diversion portal should be downstream from the Fins .
.... _Major dam foundation is a granodiorite, overlain by andesite. The
contact has been mapped. ·
-Downstream Fingerbuster structure is more complex, not a single dir-
ection but multidirectional; mainly N-S and at 300°.
Hydrothermally altered zone of weak rock also exists, running NE-SW.
-Some weathering of the contact between the andesite
(1-2 feet); no deep zones. Fracturing goes through
the hydrothermal alteration is in the diorite only.
zone is well healed~ conformable, and extrusive.
-Many slide blocks in the Fingerbuster area.
and the diorite
both rocks, but
The contact
-Some felsic dykes, but these are not a significant problem.
-Boreholes BH3 and BH4 were drilled into the present powerhouse loca-
tion; an altered zone was detected, which may require minor adjust-
ment of the powerhouse position. The altered zone cannot be ident i-
fied with any surface feature.
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-Rock quality is generally good; RQD values increase with depth.
Borrow Areas
-A: quarry in andesite for rockfi!l.
-D: impervious fill.
-E: filter material and concrete aggregates.
-H: alternative to D, farther downstream.
-general discussion on materials; core material from area D has 1ow
plasticity; core material from area H would be preferable despite
the longer haul distance.
Relict Channel
-1981 survey limited to seismic refraction survey to assess the ex-
tent of the problem. Becker drill rig not used because of budget
1 imitations.
Now known to extend to a maximum of 450 feet in depth, with an over-
all length approaching 155 000 1 inear feet at present full reservoir
level (2, 215).
-Only information on material at depth is from Corps of Engineers•
boreholes, which indicate wide diversity of alluvial deposits, rang-
ing from cobbles and boulders through to gravels, sands, and lacus-
trine clays. No data on permeabi 1 ity are av ai 1 ab 1 e.
-Serious problem for potential seepage· loss and possible piping fail-
ure unless preventive measures are adopted. Acres has allo\>~ed for
the construction of a continuous cut-off trench in the feasibility
design.
-Further field investigations are planned for the next phase
(1983/1984).
No advantage in moving the damsite upstream.
-E. Yould (APA) expressed concern at the possible serious impact on
licensing, despite the assurance that feasibility would not be af-
fected.
4.2 Devil Canyon
-Predominant rock is an argillite; the strike of the bedding plane is
parallel to the river.
-Felsic dykes run N-S, interspersed with other shear zones.
-USBR drill logs were correlated with the 13 series holes to assess a
potential linear shear zone along the river on the north abutment.
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-COE holes were relogged also -"gouge 11 confirmed the 1 inear shear
zone in the river which is not a.s significant as the known shear
zone through the ponds area. Thought to be an extension of the N-S
shears across the river. May require local treatment during con-
struct·~ on.
-The Argillite at the site is a good quality rock; RQD values good to
excellent from 100 feet down.
-Tension relief fractures are evident on the south abutment; cost
will be allowed for these during construction, but feasibility wi11
not be affected.
-Any evidence of a buried channel on the northside? Nothing found to
indicate this, although there is deep alluvium on the ponds shear
feature.
5. Report on Seismic Studies (J. Lovegreen, WCC)
- A brief s liTUllary of Task 4 objectives was given.
-Known major earthquake sources in the area are the active crustal faults
to the north and south, and the Benioff zone beneath the surface.
-Total of 200 known faults and lineaments were studied and assessed for
potential seismic activity; a screening model reduced these to 1.3
features requiring further study - 4 at Watana, 9 at Devil Canyon.
-SliJlmary of methodology for assessing seismic geology was given, together
with the methods used -these included:
geology
f i e 1 d m app i ng
magnetic and seismic refraction surveys
discussions with other research groups
remote sensing imagery
aerial and low-sun-angle photography
-Approach: What is likelihood of a fault?
Age and distribution of quaternary units.
Identify most fault-like scarp.
Trench the scarp.
Any detectable earthquake within 100,000 YBP?
Judgment and experience with other active faults.
What is the likelihood it is an active fault?
-Quaternary dates were confirmed by C14 dating, oxidation, and
weathering depth.
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5.1 Watana
Talkeetna Thrust Fault
-To the north, a 5-foot tertiary displacement was located in coal
deposits, dated at 20 million YBP~ close to the Denali fault.
-At Watana Creek some evidence of no activity in 10-20 mill ion YBP,
based on fo 1 ding.
-In the Susitna River, iron-stain deposits show no tectonic movement
across the fault, only small-scale slumping.
The most significant feature was trenched 15 km from the river;
fluvial gravels (20,000-40,000 years old), with no evidence of fault
movement. Resolution down to 1 em.
-Talkeetna Hill; the fault is vertical. No evidence of a fault scarp
or movement expressed in the morphology.
-In SUI111lary, the fault is considered to be inactive.
-{Dr. Seed) If the fault were active, what magnitude of earthquake
~'K>uld be anticipated? J. Lovegreen would not conment on this
question, since it was judged not to be an active fault.
Susitna Feature
-Evidence for the fault: to the north, Turne\' & Smith • s work on age
dating of fault material and differential cooling rates; middle
area, some mapping by Turner; seismic activity in the lower area
(mag n i t ud e 5-5 . 2) .
-Rock outcrop mapping does not agree with the 11 fault 11 alignment.
-~1agnetic tracelines give no evidence of a fault.
-No evidence of tectonic movement along the fault in Tsusena Creek.
-Tr·ench excavation across the most likely surface feature, detennined
by low-sun-angle photography, showed glacial origino No evidence of
fault mov anent.
-Joint orientation studies? No hard evidence.
-Seismicity? Strike-slip and crust faulting suggested by Gadney &
Schapiro at a peak distance of 80 km. Benioff zone is only 50 km--
this evidence appears to be incorrect.
-Conclusion: no surficial evidence for activity of the Susitna fea-
ture within the last 10,000 years.
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River Feature (KD37)
-No evidence of morphology of a structural feature, either upstream
or downstream.
Fins Feature
-This is a fault, but not considered an active fault, in view of its
1 ength (about 2 km).
5. 2 Devil Canyon
-Of the 13 features considered, only 3 are faults: KC55, KD5'2, and
KD5'43; the rest are lineaments.
-There is no evidence of fault activity within the last 40,000 years;
dyke feature shows a complete outcrop across the fault line; also
confirmed by terrace deposits.
5.3 Seismic Geology
-Magnitude of anticipated ~aximum earthquakes:
Castle 1'1:>untain
Denali
Benioff
Talkeetna Terrain
5. 4 Sei smo l 09.Y
7.5
8 to 8+
8+
5. 75+
- A new model has been developed for the Benioff zone activity; this
indicates maximum intensities up to 8.5 on the interplate zone, and
up to 7.5 on the intraplate zone, with a transition between.
-Could the 1943 ea~"thquake (7.3) have originated on an extension to
the Talkeetna Thrust Fault? This is outside the area of the oresent .
WCC study. Thought that this earthquake originated in the Denali or
Castle Mountain faults, but an extended study progro.m would be
required to consider this. Did the Review Board consider that a
further study would be necessary?
-Floating Terrain earthquake? WCC considers an earthquake magnitude
5~5-6.0 would give noticeable surficial expression within 10 km.
This is based on Alaskan and worldwide data source.
-What magnitude earthquake could occur just below the darnsite?
5.5-6.0, with a focal depth of about 10 krn.
-All 5.0-5.5 considered had active faults associated with them.
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-General discussion on the anticipated magnitude of the floating ter-
rain earthquake follo\ved. Ground accelerc1tion corresponding to
5.5-640 would be 0.35g. Dr. Seed considered that the magnitude
selected would not affect feasibility, only the extent of dam
material compaction and, hence, costs.
-General consensus was more than 5.75, say 6.25-6.50. Decision on
magnitude would be made outside the present meeting after further
studies and consultation.
-Reservoir induced seismicity: from a worldwide study all reported
instances were related to active faults; hence, RIS impacts are
expected to be minimal .
6. Earthfill Dams (D. W. Lamb)
6.1 Materials
-Core
-Fillers
-Rockfill
(D, H)
(E)
(A)
factor of 10 on required volume
factor of 8-10
factor of 5 (within 11 miles)
-Grading curv·es for material D were shown: ~0-30 percent passing 200.
-Optimum moisture content 6-7 per·cent. Permeability lo-5 cm/s.
-Material is on the wetter side of optimum and drain age wi 11 be necessary.
-Higher compaction will reduce OMC and accentuate the problem.
-Area E material wi 11 be separated into two materials for fine and coarse
filters; many cobbles must be removed.
-Area H is a core alternative source, with good grading and higher plasti-
city.
-Gener·al: ice canter".:. may be a construction problem for handling and com-
paction.
(Dr. Seed) Core material selecti.on: should avoid differ·ential compressi-
bility in the core, which causes arching action between the shells.
-Devil Canyon: a problem with the Saddle dam. No core mat.?.rial is avail-
able!. It must either be transported from Watana or material avail able at
site will be treated with bentonite.
6.2 Relict Channel Treatment
-Hydraulic gradient is 1 in 10 along the shortest route (6,200
feet).
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-General discussion on the anticipated magnitude of the floating ter-
rain earthquake followed. Ground acceleration corresponding to
5.5-6.0 would be 0.35g. Dr. Seed considered that the magnitude
selected would not affect feasibility, only the extent of dam
material compaction and, hence5 costs.
-General consensus was more than 5.75, say 6.25-6.50. Decision on
magnitude would be made outside the present meeting after further
studies and consultation.
-Reservoir induced seismicity: from a worldwide study all reported
instances were related to active faults; hence, R IS impacts are
expected to be minimal .
6. Earthfill Dams (D. W. Lamb)
6.1 Materials
-Core
-Fillers
-Rockfill
(D, H)
(E)
{A)
factor of 10 on required volume
factor of 8-10
factor of 5 (within 11 miles)
-Grading curv·es for material D were shown: 2.0-30 percent passing 200.
-Optimum moisture content 6-7 percent. Perm~ability lo-5 cm/s.
-Material is on the wetter side of optimum and drainage will be necessary.
-Higher compaction will reduce OMC and accentuate the problem.
-Area E material will be separated into two materials for fine and coarse
filters; many cobbles must be removed.
-Area H is a core alternative source, with good grading and higher plasti-
city.
General: ice content may be a construction problem for handling and com-
paction.
(Dr. Seed) Core material selection: should avoid differential compressi-
bility in the core, which causes arching action between the shells.
-Devil Canyon: a problem with the Saddle dam. No core material is avail-
able,. It must either be transported from Watana or material avail able at
site will be treated with bentonite.
6.2 Relict Channel Treatment
Hydraulic gradient is 1 in 10 along the shortest route (6,200
feet).
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-Saddle dam is required, 2,300 feet long and up to 40 feet deep.
-Material in the channel is a diverse mixture of sands, gravels,
boulders, and lacustrine clays with unknown permeabilities.
An assessment of seepage loss using an average value of 1o-2
cm/s gave an annual energy loss of 23 GWh, worth about $23 million
capitalized. There is also the danger of piping at the downstream
exit.
-Alternative solutions were considered: upstream blanket treatment
would cost $100 million, but these are notorious for not being
effective: downstream filter wqu'ld control the seepage loss but not
prevent it: continuous grout/slurry cutoff trench would prevent
seepage loss at an estimated cost of $50 million.
-Length of cutoff trench about 15,000 feet, depth up to 450 feet.
-All available data is based on Corps of Engineers' boreholes, dril-
led to rock: no material samples were taken.
-Do-nothing option is not acceptable; Acres considers continuous cut-
off trench' to be best solution at feasibility stage.
. .
-More investigations along cutoff wall possible during feasibility
study? Would cost $500,000 -$700,000 for a Becker drill rig to
provide large bulk samples. Schedule? If decision November 1,
February 1, 1982, onsite, offsite in 2 months.
-It was suggested that both cutoff wall and downstream filter should
be included for FERC license application.
6.3 Dam Design
Shell is currently assumed to be river gravel, not rockfill, using
material properties from Oroville dam. Preliminary results indicate
up·to 100 percent p.w.p. buildup. Upstream drainage will be pro-
vided to dissipate excessive p.w.p. Gravel properties not known in
detail but control of placing will govern permeaoility.
-Rockfill may be used if it proves to be safer, or a combination of
the two.
-Slopes being analyzed are 2.25:1 upstream, ~.0:1 downstream.
-Layouts are being based on 2.4:1 upstream.
-Core width is 50 percet, t of head; fi 1 ters 60-80 feet at base of
dam.
10 feet excavation in rock everywhere, increasing to 40-50 feet
under the core.
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-Allowance is being made for static and seismic settlements.
-Devil Canyon Saddle dam: assLmed sane design and slopes as Watana.
-(Panel Comments) core material from area D has SM gradings: possi-
bility of piping, since it is not plastic. Design totally reliant
on the filters to prevent piping. Material from area H is a bP.tter
option and would have fewer problems in placing.
October 7, 1981
1. Introductory Remarks (J. D. Lawrence)
2.
-Dr. Sykes and Dr. Hendron will not be attending the final day {10/8/81)
and will be reporting to Acres separately.
-{Panel Corrment) Are pennafrost and ice lenses found in the abutments at
Watana? Yes, mainly in the left abutment. How does this affect the
foundation treatment? Ice would be thawed prior to grouting and founda-
tion treatment. Have costs been allowed for? Yes. Will river alluvium
be removed? Yes.
Hydrologic Field Program (J. Hayden)
2.1 Data Sources
-Basin data up to Talkeetna.
-Gold Creek has 30 years of records, other stations have usually a
minimum of 10 years.
-Work carried out under two main headings:
(i) Regional Flood Studies -R&M.
(ii) Long-term, average monthly flows and daily flows for energy
predictions -Acres.
- A fill-in program was used to formulate stochastic 30-year flows at
other stations of interest; e.g., Vee Canyon where only 10 years of
records were available.
-Long-term flows at Watana and Devil Canyon were then derived, based
primarily on area--secondary effects were precipitation, snow melt,
and topography.
2.2 Flood Studies -
-R&M flood studies were based on other basins in Alaska with similar
characteristics. Tne results were incorporated with the Gold Creek
results for 30 years of records to derive flood flows at Devil
Canyon and Watana for various return periods-
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-There are two flood peaks per year; a snowmelt flood in June, and a
less severe glacial melt/precip·itation flood in August. Control
structures needed for the summer flood only.
-Watana floods were presented: the PMF is now 315,000 cfs, compared
with Corps value of 230,000 cfs. The increase is caused by a re-
vised PMP from the NWS, sharper temperature rise, etc. Work was
done by Acres and "''ill be ·incorporated in the Fe as i b i 1 ity Report.
-Devil Canyon floods were also presented (based on Watana being con-
structed).
2.3 Water Quality
-Recording stations were summarized.
-Will there be degradation of the downstream channel? No, it is al-
ready sufficiently armored .
-Temperature and river-level modeling studies continue.
-Sediment entrapment is about 100 percent.
-Bedload is less than 5 percent of the suspended sediment load; the
total annual load figure is similar to the Corps value. Load dura-
tion curves shown for the m~or rivers; Chulitna and Susitna about
the same, Talkeetna much less.
2o4 Ongoing Work
-Site flows continue to be recorded; these are used to confirm the
11 fill-in 11 program (v.s.).
-HEC program has been calibrated for use in predicting river levels.
-River morphology report is now available.
-Ice modeling is completed .
-Temperature modeling has been revised to allow for surficial heat
loss, but still indicates extensive open water downstream from Devil
Canyon.
-Fisheries now want extensive water releases in summer, up to 18,000
cfs. For power releases only, the releases are in excess of 9,000
cfs for 17 out of 30 years. Some compromise will be possible after
negotiation with the Fisheries Mitigation Task Force. Reservoir
operation may also need to be modified.
-Water temperature? A multi-level intake is being designed at Watana
to maintain water temperature as close to normal regime as possible.
Releases from Devil Canyon will be sensibly at a constant tempera-
ture of 39°F.
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3. Energy Simulation (J. Hayden)
4.
Energy output from the model is assumed to match the shape of the demand
curves. Peak load is in December; peak flows are in sumner; seasonal
storage is used to maximize firm energy.
-Watana reservoir provides almost total regulation.
-Critical dry periods? For a single dry year, the return period is about
1 in 100 years; for 2 consecutive dry years, the return period is about 1
in 400 years.
-Constraint is externally applied that the reservoir should be full at the
end of the 30 years of hydrological record.
-\~ith both Watana and Devil Canyon constructed, the total energy demand
can be met with no thermal backup from 2,000 to 2,003 (medium load growth
forecast.)
-Further extension of the tailrace tunnel at Devil Canyon has been found
to be cost-effective. The net head is increased by about 30 feet and
annual firm energy is increased by about 100 GWh. . .
-Post-project flows from Devil Canyon vary from 6,000 to 10,000 cfs be-
cause it is operated as a base load station; peaking only at Watana.
-(Panel corrment) What are temperature and flow impacts on the salmon?
Temperature effects concern the incubation of the eggs, predation, and
thermal shock. Flow impacts concern the possible isolation of spawning
salmon in minor tributaries, owing to low power releases in critical
months.
Reservoir Level Optimization (J. Hayden)
-Firm energy can be increased by two methods:
(a) increased dam height; and
(b) increased drawdown.
-(a) Firm energy variation with dam height: the flow is 98 percent reg-
ulated; hence, a linear variation of firm energy with dam height.
Dam height was optimized using incremental costs compared with
increnental system costs from OGP5 runs. The cqrve is very flat,
and any level between 2,175 to 2,215 would be acceptable. Upper
1 imit of about 2,240 determined by flooding 1 imitation upstream at
Fog Creek.
-Results will be checked later using the Batelle load growth forecast, es-
calation rates, coal values and so on .
-Devil Canyon reservoir level is fixed at Watana tail water level, 1,455,
to fully utilize the available head.
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-(b) Firm energy increases with drawdown up to 190 feet. Above this
1 evel there i-s 1 ittle or no improvement because of low head energy
loss in the dry years. The maximum drawdown (190 feet) is
cost-effective; i.e., the capitalized extra firm energy value
exceeds the increased cost of intake works and approach channel.
5. System Model Studies (John Hayden)
6.
-Economic parameters have been used {0 percent inflation, 3 percent dis-
count rate.) The OGPS model in-corporates all existing and planned power
developnents in the Rail belt Area, and allows for annual costs of fuel,
operation and maintenance, and financing charges.
-Watana is assumed to come on-line in the fall of 1993; Devil Canyon on-
line in the year 2000. The Intertie is allowed for by increasing the
system load factor from 0.52 (present) to 0.62.
-Sensitivity analysis has been carried out on discount rates, fuel costs,
rate of load growth, etc.
-11 Devil Canyon first 11 option was also considered, with suitable adjustment
of costs (access road, extra cost of spillway facilities). Slightly in
favor of 11 Wat ana first 11 but not a lot.
-(APA comment) Could Devil Canyon be brought on line earlier, if required,
for a major industrial expansion program? This would be addressed in the
Feasibility Report. Could be justified only by a significant increase in
demand; would have significant impact on manpower and other key resources
in Alaska.
-Reservoir levels: the June flood is absorbed, but the August flood
causes some spilling.
-Filling: time taken is dependent on inflows and compensation flow down-
stream. Freef:board will be maintained sufficiently to absorb the
1-in-500-yeat flood during filling.
-(Panel comment) Regarding the optimum dam height, can the cost of the
dyke/saddle dam be justified? A 25-foot dyke constructed on 25 feet
permafrost could suffer slumping failure under earthquake shaking. De-
sign of the dyke should be carefully considered, particularly the cutoff
wall below the dyke. Earthquake and permafrost conditions are the major
design concerns for foundations in Alaska.
Installed Capacity (J. Hayden)
-Assessed by estimating the peak load on Susitna, knowing the peak demand,
and the available system energy from alternative sources. Susitna used
at peak (Watana) or base (Devil Canyon).
-Using the med i lJ11 1 oad forecast, the peak load on Watana increases from
567 MW (1993) to 626 MW (2000).
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-Peak load on (Watana + Devil Canyon) increases from 1,029 MW (2000) to
1,119 MW (2010), again using the medilJll load forecast.
-By extension of the method beyond 2010, the Susitna demand would increase
to about 1, 600 MW by the year 2040.
-From these stud~es the following capacities have been selected for over-
all developne~··~t:
Watana
Dev i 1 Canyon
900 MW
600 MW
(6 X 150 ~1W)
(4 X 150 MW)
-Surface powerhouse or underground? Costs favor the underground power-
house, basically because of increased cost of penstocks wi~h a surface
powerhouse.
-Number of units insta11ed? Minimum requirement at Watana is 4 units; 6
units give greater flexibility of operation, i.e., higher efficiency at
part load conditions. Extra cost, about $30 million, can be justified by
value of extra energy generated. Present layouts are based on 6 units of
150 MW.
-At Devil Canyon, 450 MW is required to generate all available energy at
100 percent load factor. Final design requires 600 MW. Hence, 4 units
of 150 MW were se 1 ected ~
Dykes on Permafrost (M. Vanderburgh)
-In view of Panel concern over the dyke at Watana, details were given of
design of dykes constructed on 40 feet permafrost in north Manitoba; 30
feet high, constructed on varved clays/silts. Sand drains were used to
facilitate settlement resulting from permafrost thawing. Up to 6 feet
settlement has been measured over 20 years.
J: 8. Spillway Design (J. Hayden)
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-Summary was given of flood flows under 4 main headings:
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( i i)
(iii)
(iv)
Diversion flood
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Design flood
PMF
1 in 50 years.
1 in 100 years (nitrogen problem).
1 in 10,000 years.
Structures have to be designed to handle these flows.
-Watana: design requirement is to avoid nitrogen supersaturation problems
for floods up to the 1-in-100-year event. This can be achieved eithe.r by
a cascade spillway on the left bank or by a tunnel spillway on the right
bank with Howell Bunger valves. Cascade spillway is more expensive, and
quality of the rock is very doubtful; hence, high maintenance costs are
anticipated. Also, the spillway is pushed downstream by the known shear
zones which again increases cost.
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-Powerhouse flow is included for flood routing up to the 1-in-100-year
event; above this flood the powerhouse flow is not included.
-Flows up to 10,000-year floods are taken partly by surcharging the reser-
voir (up to 4 feet); then the main spillway gates are opened and excess
flow is discharged to the river by chute and flip bucket.
-For floods in excess of the 1-in-10,000-year event, reservoir surcharge
is increased (7 feet) and excess flow is taken by the main spillway and
an emergency spillway; a fuse plug dam in the emergency spillway retains
water to the 10, 000-year flood. Emergency spillway discharges into
Tsusena Creek.
(Panel comment) Uesign of fuse plug dam to fail at a critical level is
difficult; may be better to have positive control, e.g., gated structure,
but at higher cost. Also, depth of fuse plug is excessive and could lose
valuable water when plug fails.
-Operating characteristics shown for two floods:
(a) 1 in 100 years -Howe 11 Bunger v a 1 ves opened for about 14 days.
(b) 1 in 10,000 years -Main spillway operates full bore for 3 days
(reservoir initially empty) or 5 days from 2,215
level.
In the event of seismic or other emergency, reservoir could be drawn down
200 feet by service (tunnel) spillway and powerhouse, then low-level out-
let would be opened •
9. Watana Layout Studies (J. D. Lawrence)
-Original layouts showed 2 diversion tunnels, crest level 2,225; 2.75:1
upstream slope, 2.0:1 downstream.
-Points of design concern were tabulated for Watana and Devil Canyon.
Major design variations concern the types of spillway.
-Copies of the current design criteria were issued to the Panel Members.
-Basic methodology for scheme selection was described:
(i) From DSR--8 layouts.
(ii) Screened to give 4 best options.
(iii) Further developed to select 2 best options, of which the
chute/flip bucket spillway is the current preferred option.
-Selection procedure and layout variations were described in detail, to-
gether with broad conclusions drawn from each layout .
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9.1 Preliminary Layouts (8~al~ernatives)
-Dam centerline should be as far upstream as possible.
-Minimize upstream dam slope.
-Diversion~ 2 tunnels on right bank with low-level outlet.
-Powerhouse underground.
-Single spillway unacceptable; use separate emergency spillway.
-Chute/flip spillway preferred.
-Cascade spillway to be investigated further.
9.2 Preferred Layouts (4 alternatives)
-Considered from the following aspects:
technical feasibility
construction methods
component size
cost
environmental impact
operation
schedule
-Four layouts were described in detail, the main differences being
associated with the spillway location and type and the powerhouse
1 ocation.
-Cost comparisons were shawn, favoring the chute/flip spillway op-
tion.
-Conclusions drawn:
(i) Lower upstream cofferdam to reduce general site congestion.
(ii) Major structures on the right bank.
(iii) Keep left-bank spillway as an option.
-Dam design is now being carried out, and upstream slope has been re-
duced to 2.4 to ease congestion and reduce diversion costs.
9.3 Arch Dam Alternative
Layout shown, geometry plus main structures.
-Cost estimates show the rockfill dam to be cheaper, with a concrete
unit rate of $150 per cubic yard. (Compared with $210 for Devil
Canyon.) This is likely to be low; hence, rockfill alternative was
selected.
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10.1 Hatana
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-Flows: diversion--the routed l-in-50-year flood, 76,000 cfs.
reservoir filling--up to 10,000 cfs.
operation--up to 30,000 cfs for emergency drawdown .
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-Current layout was described in detail. The upstream diversion
portal will be kept downstream from the Fins feature.
-Two options were initially considered:
(a) 2 pressure tunnels
(b) 2 free-flow tunnels
-Optimum diameters were 30 feet (a) and 35 feet (b) , vii th maximum
design velocities of 50 feet/second.
-Plugs and gates will be constructed in one tunnel in the winter
while the diversion flow passes through the other~
-Selected scheme has one pressure and one free-flow tunnel with
suitable energy dissipating devices for emergency releases. The
right diversion tunnel is also used as an outlet for one of the two
tailrace tunnels, to ease site congestion downstream.
-Operating curves shown for emergency drawdown condition. Four
months would be required to level 2,000; about 30 months to 1,800
level. The reservoir can be held at 1,800 level if necessary.
-Gates would be needed on the pressure tunnel to construct the con-
crete plugs; these could be designed for emergency use to give
extra drawdown capacity.
-Summary of recommended layout:
50-year flood, (83,000 cfs) routed flow 76,000 cfs. Optimum
cofferdam height reduced 40 feet to ease site congestion; 2 x 35
feet diameter tunnels (1 pressure, 1 free-flow).
-(Panel comment) The maximum cut on the· upstream portal is about
300 feet. It would be worth reducing this by any possible means,
e.g., separate cofferdam across portal entrancey
10.2 Devil Canyon
-Single 35-foot pressure tunnel -no byrass flows required, these
will be provided by Howell Bunger valves in the dam. Design flow
is 52,000 cfs (routed through Watana).
-Portals will almost certainly ba moved from the positions shown,
from topography considerations~
11. Power Development (J. Hayden)
-If Watana dam height were to be lowered 100 feet because of problems with
the relict channel, $5.2 x 109 could be spent on the Susitna develop-
ment; actual cost would· be $5.0 x 109; hence, the project would still
be viable, although annual firm energy would be reduced from
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6,100 to 5,400 GWh. This represents a capitalized value of $700
million in reduced energy from Susitna.
-Summary of power develoJlT}ents at present envisaged.
Watana -6-unit powerhouse, underground, fed from multi-level
intake.
Devil Canyon -4-unit powerhouse, underground, from single-level in-
take; one machine discharging at the dam, three machines
· discharging over 1 mile downstream to gain extra head.
12. Tidal Power (C. Debelius)
-Part of an overall study of energy alternatives, broken down as f0llows:
(i) Site reconnaissance and selection.
( i i)
( i i i)
( i v)
( v' . )
(vi)
(vii)
Evaluation, based on medium and high load forecasts.
Tides -top of inlet 20 to 25 feet, maximum 40 feet.
Cascade alternatives, using time phase difference.
Computer model developed to assess energy output for a given con-
figuration.
Mils/kwh not sensitive to total energy generated over a wide range
from opt ~mum.
Caisson Construction -floated in and sunk on prepared sand bed.
Power available is large compared with the system requirements.
Hence, storage will be required to use the available pulses:
(a) compressed air energy storage;
(b) hydroelectric storage; or
(c) industrial usage on same pattern as available pulses.
(viii) General environmental considerations .
(ix) Risk analysis.
(x) FERC licensing -similar to Susitna.
(xi) Costs? Same order mils/KWh as coal-fired thermal .
(xii} Further work? Sedimentation should not be a problem within the
f i r s t 50 years .
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October 8~ 1981
1. Introductory Remarks (J. D. La~·ence)
-Panel would be ~iting their report after the morning session; lunch
would be brought in.
2. Devil Canyon Dam Design (R. K. Ibbotson)
-Arch dam is to be constructed at the upstream end of the canyon in an
asymmetrical valley.
-Tension cracks and general instability at the upper left abutment in-
crease excavation by about 100 feet in the area of the thrust block.
-Geometry presented in graphical form .
-Properties of materials assumed were presented .
-Allowable tensile stresses: -250 psi (normal)
-750 psi (dynamic)
-Rock modulus (2 x 106 psi) not altered, but work on other dams
indicates about 10 percent change in stresses for a change in modulus of
a factor of 2.
-Details of assumed temperature variation and combined load conditions
were presented.
Normal loading results: Load case ULl
Load case UL3
-27 psi tension
+1100 psi
-393 psi at left centilever
+1180 psi
-Dynamic analysis: mean response spectrum was shown. Dr. Seed queried
the term 11 mean 11 ; the normal acceleration used would be 0.84 percentile
(say 1.35 x 0.35g = 0.47g). Also, design earthquake may increase as a
result of discussions with WCC (v~s., October 6th Report).
-Extreme loading results: EL.l(i)
ELl(ii)
EL2
-729 psi upstream crown centilev~r
+3600 psi.
-577 psi crown centilever
-2000 psi in arches.
-1392 psi in crown of upper arch.
(ELl assumes 0.5g acceleration and 5 percent damping factor; EL2 assumes
0.4g acceleration and 10 percent damping factor.) 10 percent damping
factor is applicable for this type of arch dam, based on previous
experience.
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-Pseudo-static analysis was then carried out assuming vertical cracks and
construct·:on joints open up to 50% of the dam height: USBR progr001 on
reduced cantilevers gave maximum tensile stresses of -322 psi in the
arch; with reduction in hydrodynamic loading to 60 percent because of the
constricted approach and the valley shape, the maximum tensile stress re-
duces to -251 psi (EL2).
-(Panel Comment) M. Copen confirmed that Jlcres design approach was very
conservative.
3. Devil Canyon Spillway Studies (John Hayden)
-Synthetic flood flows, routed through Watana.
-Diversion flow, taken through a single-gated pressure tunnel, eventually
plugged.
-Flood-handling philosophy is similar to Watana:
( i) Up to 1-i n-100-year event - 5 Hewell-Bunger valves set in the dam.
( i i) Above 1-in-100-year event -chute/flip bucket on main r·i ght bank
spillway; alternative stilling basin has been rejected on cost
grounds, as well as lack of precedent for this head.
(iii) Above 10,000-year event -fuse plug dam in an emergency spillway
channel is designed to fail: passes flow up to the PMF.
-(Panel comments) Main spillway on the right bank will require excessive
rock bolting and support work. Had consideration been given to a tunnel
spillway, possibly using part of the diversion tunnel? This would be
difficult to fit into the available space, and intakes would be a
problem. However, it would be given further attention.
-Concrete spillway structure on the left bank? Not advisable because of
the depth of all uvi urn.
-Fuse plug dam: same comments as for Watana. Height is excessive and
would result in extensive energy losses; better to be lower and wider,
with a flared approach. ·
-Erosion of river channel caused by chute and flip bucket would tend to
raise the tail water level, but with the proposed extension of the tail-
race tunne 1 6, 000 feet do\vnstream the station output would not be af-
fected.
U 4. Devil Canyon Layout Studies (J .. D. Lawrence)
-Position was suiTJ11arized after the Developnent Selection Report (June
1981), with the Design Criteria being used at that time.
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-Major design considerations and concerns were summarized.
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4.1 Dam Selection: (a) concrete thin arch dam (preferred option).
(b) fill dam alternative.
-For the fill dam alternative, a brief block estimate was carried out
based on steep upstream slope and assi.Jlling that all necessary mater-
ials would be available. The cost was about the same as the thin
arch dam, but likely to rise significantly because of lack of data
on materials (subsequently proved to be true). Hence, the fill dam
alternative was not considered further .
-(Panel comment) Was a concrete faced rockfill dam considered? Yes,
but rejected on technical grounds: settlement problems under earth-
quake motions and thermal movements and rotations of the abutment
concrete slabs in the extreme temperature range encountered in
Alaska.
-(Panel comment) Dr. Merritt and Dr. Seed did not agree that con-
crete faced rockfill dams were unsuitable in seismic areas, and con-
sidered seismic settlements were overestimated; only about 0. 25 per-
cent settlement had been observed in a 400-foot dumped rockfill dam
subjected to 0.36g earthquake. The settlement for rolled rockfill
would be even lower, about 12 inches, not 1-1/2 percent height; this
is very conservative. Concrete-faced rockfill dams are inherently
very stable; with upstream slopes of 1.3 to 1.8 because of no pore-
water pressure problems.
-Would only be worth changing if economica·lly advantageous, in view
of present advanced stage of the work~
4.2 Layout Stud1~
... Three alternative layouts were described in detail and a tabular
presentation of costs was shown. The original orifice spillway
through the dam was removed to simplify the arch dam design, and
replaced by 5 Howell Bunger valves through the base of the dam.
These handle floods up to the 1-in-100-year event.
-Thr·ee alternative layouts are different in the location and type of
the main spillway, which handles floods in excess of the 100-year
event:
(i) chute/flip on right abutment
( i ·i) chute/flip on 1 eft abutment
(i·ii) stilling basin on the right abutment
-Right bank chute/flip is the preferred option, based on cost
grounds_. Further study will be carried out on the tunnel spillway
alternative mentioned this rnorni ng.
... Env·ironmental flow, Devil Canyon to Portage Creek. In view of the
extension of the tailrace tunnel, compensation flow will be required
to maintain flow downstream from the dam. One small turbine will be
installed to pass an acceptable flow (1,000 cfs?) .
.
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5. GeneraJ
-Dr. Seed was given figures on cost for rockfill and gravel fill at Watana
(to detennine relative suitability for·design purposes). In response to
a query on the practice of alternate layering of rockfill and gravel
fill, Dr. Seed considered this unacceptable; possibly a rationale of what
actually occurs when constructing dcms, i.e., fines trapped on top of
layers of rockfill, giving 'Jo\11, vertical penneability.
General presentations by Acres staff and discussion of matters arising
terminated at 11:30.
-Panel Report was presented at 15:15, in draft form.
6. Closing Statement (D. D. Wozniak, Project Manager, APA).
-Preliminary date for the fourth and final External Review Board Meeting
was scheduled for· January 11, 1982, in Anchorage. This date will be con-
firmed by end of October 1981.
-Dr~ Sykes and wee are to discuss and confirm the anticipated intet1sity of
the Floating Terrain Earthquake.
-Pane 1 Report on ~teet i ng No. 3 wi 11 be typed by Acres Jlmeri can in draft,
and returned to APA for issue.
Reported by:
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ALASKA POWER AUTHORITY.
SUSITNA HYDROELECTRIC PROJECT
External Review Board Meeting No. #3
MINUTES OF MEETING HELD ON
October 6 -8, 1981, BUFFALO, NEW YORK
APPENDIX A Supporting Documentation
P5700 .. 13
Copies of viewgraphs, etc., presented at the
meetings and additional to that provided in the
advance Information Package .
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ALASKA POWER AUTHORITY
SUSITNA HYDROELECTRIC PROJECT
External Review Board Meeting No. #3
MINUTES OF MEETING HELD ON
October 6 -8, 1981, BUFFALO, NEW YORK
Presentation on: Geotechnical Field Program-J. Gill
P5700.13
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USBR
COE
COE
1950-1953
1975
1978
ACRES 1980-1981
WATANA
EXPLORATIONS sur~~1ARY
RECONNAISSi~NCE
RECONNPJ SSANCE
22500 LF SEISMIC REFRACTION LINE
28 BOREHOLES (30-600 FT DEEP)
18 AUGER HOLES
27 TEST PITS
47E65 L.F. SEISMIC LINES
10 PIEZOMETERS~ 13 TE~P. PROBES
.
7 BOREHOLES (300-955 FT DEEP)
39 AUGER HOLES
41 TEST PITS (APPROX)
63000 L.F. SEISMIC LINES
q PI EZOr·~ETERS
3 THERMISTER STRINGS
r-~ATER I ALS TESTING
COE ROCK TYPE PETROGRAPHIC ANALYSIS
FILTER AND CORE MATERIALS GRADATIONS
' . CORE MATERIALS STRENGTHJ CONSOL.
ROCK STRENGTH
ACRES (IN PROGREss) ROCK STRENGTH) PROPERTIES
FILTER AND CORE GRADATIONS
SAMPLE MOISTURE ANALYSIS
CORE MATERIALS PLASTICITY) PIPING
POTENTIAL) STRENGTH
FILTER r~ATERIAL ANALYSIS
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USBR 1~57-19EO
COE 1978
ACRES 1980-1981
USBR
DEVIL CANYON
EXPLORATIONS SU~~ARY
22 BOREHOLES
19 TEST PITS
(20-150 FT DEEP)
1300 L.F. SEISMIC REFRACTION LINE
7 BOREHOLES (150-750 FT DEEP)
8 AUGER HOLES
E TEST PITS
lEOO L.F. SEISMIC LINE
r·1ATERIALS TESTING
AGGREGATE SUITABILITY TESTS
AGGREGATE GRADATIONS
ROCK STRENGTH) PROPERTIES
ACRES (IN PROGRESS)
ROCK TYPE PETROGRAPHIC ANALYSIS
AGGREGATE SUITABILITY
AGGREGATE GRADATIONS
ROCK STRENGTH) PROPERTIES
ROCKFILL SUITABILITY (FOR SADDLE DAM)
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ALASKA POWER AUTHORITY
SUSITNA HYDROELECTRIC PROJECT
External Review Board Meeting No. #3
MINUTES OF MEETING HELD ON
October 6 -8, 1981, BUFFALO, NEW YORK
Presentation on: Geotechnical Interpretation -S. Thompson
P5700.13
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ALASKA POWER AUTHORITY
SUSITNA HYDROELECTRIC PROJECT
External Review Board Meeting No. #3
MINUTES OF MEETING HELD ON
October 6 -8, 1981, BUFFALO, NEW YORK
Presentation on: Earthfi11 Dams-D .. W_ Lamb
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CORE r1ATER.L~L
PRELIMINARY DESIGN VALUES
OPTi~1Ur1 MOISTURE (95% STD I PROCTOR)
OPTI~1Ur1 DENSITY
BULK SPECIFIC DENSITY
6 %
7.5%
129-133 PCF
2.67
( 4 IN.MOLD)
( 6 IN. MOLD)
PERrEABILITY (MINUS 1 INCH) lo-5 eM/SEC (4.4 INDIA.)
TRIAYIAL TEST DATA:
TYPE Q -UNSATURATED, UNCONSOLIDATED, UNDRAINED TEST
(ANGLE OF FRICTION PHI, COHESION) 35° 0 IlL!. TSF
(OPTIMUM WATER -4%)
33° 0.6E TSF
(OPTIMUM WATER CONTENT)
2° 0.4Li TSF
(OPTIMUM PLUS 4%)
TYPE R -CONSOLIDATED, UNDRAINED HITH BP.CK-PRESSURE
EFFECTIVE STRESS RESULTANT ANGLE 37°
12° 1.1 TSF (OPTIMU~ WATER CONTENT)
13° 0.52 TSF
(OPTIMUM MINUS 4%)
CONSOLIDATION TESTS: (4.~ INCH MOLD, 3/4 INCH MINUS MATERIAL)
REMOLDED, DRAINED, 95%STANDARD C0~11 PACT!ON
PERCENT STRAIN OPT-4%
REVISED 10/06/81
1 TSF
1(1 ..........
32
0.85%
2.38
L\ 182
DPTI~1Ur~ OPT+Li%
0.7E% 2.12%
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TYPE OF rATERIAL A~OUNT REO. EST. AVAIL. SOURCE
IMPERVIOUS
FINE FILTERS
COARSE FILTERS
ROCKFILL
GRAVEL FILL
TOTAL
REVISED 10/06/81
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AREA E FILTERS)
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WATANA BORROW AREA D
ENVELOPE OF IMPERVIOUS ~1ATERIAL GRADATION CURVES
(MAJORITY OF SAMPLES LIE IN DARK BAND SHOWN ABOVE)
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Grain Size in Millimeters
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SAMPLE NO. MOISTURE. I DRY
CONT (NT DENSITY LL PI CLASSIFICATION B. Df~·;;fllplriON
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TYPICAL CORE MATERIAL GRADATIONS -WATANA AREA D
APPARENT VARIATION WITH DEPTH: WATER CONTENT DECREASES
GRADATION BECCMES COARSER
NUMBER OF FINE:S DECREASES
(SAMPLES FROM 0-21 FEET)
BORROW AREA D
SU~RY OF GRAIN SIZE DISTRIBUmtONS
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MAX I MUM DRY! 0 ENS I TY I A) ]3 9 P3
OPTIMUM WATER CONTENT 6-9.3 "!.
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SIEVE ANALYSES:
COE -AREA D
ACRES -ARF.A D
-AREA H
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WATER CONTENT IN %
WATANA IMPERVIOUS MATERIAL
PROCTOR COMPACTIONS
% PASSING 2"
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Grain Size In Millimeters
GRAVEL I SAND
.• I Coarse I Fine I Coarse I Medium I Fine 1 SILT or CLAY
S ENCOUNTERED ,
sAMPLE No. CLASSIFICATION a DESCRIPTION -I
Engineering a Geological Consultants
ANCHORAOE I"'AI RB\ANKS A LASKA JUNEAU
REVISED 10/06/81
COMPOSITE GRADATION CURVES FOR BORROW AREA E
SUSITNA HYDROELECTRIC PROJECT
FILTER & AGGREGATE SOURCE AREA
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f'DRAWN BY
APPROVED BY 1
DATE B/21/81
PROJECT NO. 052506
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GRAIN SIZE IN MILLIMETERS
COBBLES GRAVEL . SAND - - ' UNIFIED SOIL [ I ---_ COARSE I FINE lcoARsEj. MEDIUM 1. FINE -i SILT OR CLAY I ~~~~s~~CATION
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IIUIIIL BUFFALO, NEW YORK
' I WATANA FINE FILTER DESIGN CRITERIA
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CHANNEL SPECIFICS:
vlATANA DA~~S I TE
RELICT CHP~NNEL
r~AX IMUr, OBSERVED DEPTH
AVERAGE DEPTH
L~5L:. FEET
200
~1 IN I ~\UM OBSERVED ~~ IDTH 1L~.Q75
SHORTEST FLOH PATH (FR0~1 RESERVOIR) 6200
HEAD LOSS -~AX. OPER. POOL 590
AVERAGE GRADIENT 1 IN 10
Cl'TOFF SCHE~~E SPECIFICS:
TOTAL LENGTH OF CVTOFF 14075 FEET
MAXIr11U~1 DEPTH L~.oo
AVERAGE DEPTH 200
SADDLE DAr·~:
TOTAL LENGTH 2300 FEET
~1AX IMUf~ HEIGHT 40
AVERP:GE HEIGHT 20
OVERB~RDEN DEPTH -MAXIMcM 300
-AVERAGE 165
RIPR/l.P SHORE PP.OTECTION REQl!IP.ED ~ono -' I'-'
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ALASKA POWER AUTHORITY
SUSITNA HYDROELECTRIC PROJECT
External Review Board Meeting No. #3
MINUTES OF MEETING HELD ON
October 6 -8, 1981, BUFFALO, NEW YORK
Jl Presentation on: Hydraulic Studies -J. Hayden
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DATA. COLLECTION PROGRAMS AT MAJOR STATIONS
IN TI-lE SUSITNA ·RIVEH BASIN
(1,
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0
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~tJsltna River near Denali r: I • I
susltna2 Rlyer pt yee· ~-~ny~n '
.Susltna River near Watana ·Dafoslt• .• X X
Su•ltna R lver near Devil~ Con)Cn . ' . X , . . .. .
, • ! I I I Susltn.a River •t Gold Cr3ek X . . .
I
Chl..lltna ·River ne•r Talkeetna X .
Talke•tn~ River near TAikeetn• · . ,X .. . ....
' . . . . . 4 . .
Sualtn.a River near Sunshine ·x I .. . . . . .
Sk~'ntna R1ver near Skwentna : I X I I -.
v.~tna River neat• Susltna Station I X I I
Susltn~r River o~t Sualtna Station I X I I
.
NOTES:
(1) Parameters Measured listed In Appendix F
(Z) Contlnuoys water quality monitor Installed
(3) Proposed ~
( -4) Proposed .. dat.o coll•ctlon tp 1begin ·1901
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1961-1972, 1900-Present
X x X {1900-Present R&M)
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11958-19.72, 1980-Present
_1964-Present
I I f 1969-.1971 Part.~ ( 1976-'Bo NWS)
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SUMMARY OF PRE-PROJEC'i FLOW CONTRIBUTIONS BY MONTH AT TALKEETNA
Flow Contribution by: * Total
Flow D/S
Chulitna Talkeetna Susitna Talkeetna
--~--
October 4859 2537 5580 12976
November 1994 1187 2435 5616
December 1457 838 1748 4043
January 1276 67i 1438 3385
February 1095 565 1213 2873
March 976 492 1085 2553
April 1158 557 1339 3054
May 8511 4176 13400 26087
June 22540 11910 28150 62600
July 26330 10390 23990 60710
August 22190 9749 21950 53889
September 11740 5853 13770" 31363
.
Annual 8748 4086 9707 22429
* Discharge data from U.S.G.S. records
I~
.. •-• 1111 -IIIIJ IIIII ¥1M 1111 1P!1 _. Bl mill 1111 -.. 111!1 ~ Ill
AVEGAGE MONTHLY FLOWS <ET3/s)
r·10NTH WATANA DEVIL CANYON GOLD CREEK SUNSHINE
POST PROJECT POST PROJECT PRE PROJECT POST PROJECT PRE PROJECT POST PROJECT
OCT 7095 7898 5639 8343 13,690 16,394 .. ~~v t·t> i 'fV 8746 9070 2467 9250 5)829 12,613
DEC 93LJ6 9596 1773 9735 4.~199 12)161
JAN 8676 8872 1454 8982 -. --~ !!!!!...!
.J J LJ :::JO 11 Al"'\f)
.LL" UL .
FEB 9238 9408 1236 9503 2,952 11,219
MAR 7540 7683 1114 7764 2,631 9"280
I l . I APR 6919 7090 . 1367 7184 3,177 8,994 t •0 l. J I'· f·1AY 5470 7341 13317 8381 27"717 22,781 ,' ·\:
-:.:'/ ;
' ,\1
•t
' i .
~ .. ~ ..... , JUN ~765 7871 27928 9598 64.~198 45)868
JUL 6002 8259 23853 9513 63,178 48,839
AUG 10920 13168 21478 14424 55,900 48.~845
SEP 9555 11208 13171 12121 32,304 31.~253
I' .,
~a I' C£U% =·~~ .................................. .a .. -. .. Rm .... rw .. BR .. ~ .......... ~ .. ~~.-.. -..-~-.aNMm-.m=.--*aK--~----------~~--------------
~.. .1 ,: ':· ~
•:,~}'!
~--~--~-~-~~-~-~~~~
r10NTH
JAN
FEB
~1AR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
AVERAGE RESERVOIR LEVELS
~/AT ANA
LEVEL <FT) VOLUME
TO FILL <MILLION A.C. FT)
2168 1.834
2154 2,332
2142 2.734
2131 3~084
2140 2_,787
2172 1}681
2196 0.816
2206 0.390
2208 0.327
2204 0.490
2193. 0.899
2180 1~379
DEVIL CANYON
LEVEL <FT)
J.LJ55
1455
1LJ55
1455
1455
1455
1455
1455
J.LI55
1455
1LJ55
1455
I . l
~) 1
.I -~
' l .-.
' -""")> _, , -~ -..... ~ ' • ~ . '$. --~ • ' ~.,t .. ' .• " •
~ .. ,. t ~ -~ ~ . ... ~ -· .-~,. ~ :? ,. \....,. a ' .t , .. • ...
RETURN PERIOD
1:50 YEAR
ANNUAL
1:100 YEAR
ANNUAL
SUNf1ER
1:10_,000 YEAR
ANNUI\L
PMF
AVERAGE
ANNUAL
(1) NATURAL INFLOW
'!;:;:
FLO\~
7 FT.:> IS
8l4~ 000
92.~000
70_,000
156_,000
315.,000
7.~860
liD .. 1111 Ifill ~-~~ ~ ~ ~ riRI
PEAK FLOOD __ flJllis_
HATf\N.A DEVIL CANYON
,........_ ...
VOLUME DISCHAHGE . ROUTED D ISC~:ARGE
OF FLOOD IN FLO~/
FT3/S f·1 ACRE FT
1.56 68,~000 52.~000 52.~000
1, 7L~ LJ5., 000 5LJ,~ 000 5LJ ,~ 000
45.~000 54_,000 54_,000
3.67 120_,000 140,000 lLJO.~ 000
9~24 270.,000 325..-000 300y000
8.~960(1)
< ~ "~·,
I
I WATER QUALITY -PREPROJECT
I SUS ITNA RIVER AT GOLD CREEK
I AVG,~FLOW AVG, SUSPENDED SEDIMENT ~,ONTH FT'/L TEMPERATURE° F LOAD TONS/DAY I
Ocr 5; 639 35.2 1.~600 I Nov 2.~467 33.6 230
I DEc 1)773 32.0 100
I JAN 1;454 32.0 70
I FEB 1.~236 3210 45
I MAR 1)114 32.0 40
APR 1.~367 37.0 60
I MAY 13.~317 41.9 12.~200
JUNE 27.~928 45.5 69.~900
Jut:. 23.~853 50.9 48.,200
AuG 21.~ lt79 49.6 37)700
SEP 13.~171 42.3 11.,900
I
I
I
~6r---------~----------~------·---r------~--r---------~----------r---------~ I I . I
ANNUAL SUSPENDED SEDIMENT DURATION CURVE (REVISED l . j
SUStTNA RIVER AT
1-\'~~~---t------+-----~.SUSITNA STATION -·------1-----+-------.
MACLAREN RIVER
NEAR PAXON
SUSITNA RIVER AT
GOLD CREEK
SUSI'INA RIVER AT
VEE CA(IYON
·•
102 ~--------~--------~~--------~---------~--------~~--------~--------~ o to zo Y.> 40 so ·5o 0/o OF TIME SUSPENDED SEDIMENT DISCHARGE EX:EEOEO DURING YEAR
~ ~J
IJ
c
tJ
r:
Lt
f ~ 6
L
0 0 l 0 0 0 8 r-1 \ \ 0 N 8_ 0 ..... 0 a 0 ~ ~~------~------------~------0 --~----~-------~~\~,------~l----~----~.----------~--~---+-----------------------~ e ·---· \ I. ~ I N r-.-~~---~~~-,-----~------,_--------~\~~--~----~~~~if~i!~---~ l c ,r-~----~~--~~---------~---------------------~~--~------~------~~----~----------------------~ ~ . : ·~ \ I . '1\. :l . . . i I • i : . w ~ \!, "'. ,. : ~--. I. --~~r-~----~~--~~~·--~·~"'~~----------~~~·~~-~--~~~~xu-----T----------------------~ 6 ~ QC 5--~--------------~'~~--·--~-y~----------~~~~-~~-~----+-----------------------· i~·-~~~~~~~~~~~~~~~~i~9+~~u~~~~~~~·;~~·~~·~~-====·~~~========~======~3
0
0 n
0 ....
0
... 1
0 =
0
"'"
·~----~------·------------~~------~~--~-----·----------~~-~~~--~~~--~·----·----~~----------------~----------------~~ ! A". \ I :\ .....___ _____ ;;.>
~ -~ . ·-z ...,...
'\
-~
\ . -
~------------------~----------------------------------~----~~-~=~------~·\~~~---~·\~-----------------------~~~-~
. I •
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T ..
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;· ,, T
•. 1 .• , • !•;
1\
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-\
\
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• • 'I
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tl
i ...
' '· j'
\-.--------.:..
\.
'
\ . \ ...
-i'\ l 1 j
.,.., ' '. ~ .. . I ' g: •:11·. t I ' I • ~ I • l I . • I ~ : • • • ~ t
-~~;~--~~~·~''---~-~~--c---------~-----------------'~'~!~i-·~·=~!--~1!~· --·~:J~t~·~:~ '·~'·~:-··~·~~-~·~'~:_· __ ~, __ ·~----~--~----------; ;; l : l " i
l%1
. I . 'I ' ·.·1 'I '. I. . . I . -"'·-
(• . . : .•• I ; I -t'!';:! ; . . • . f..:: I I. I
• I 1 ' I • • • •
0: "" l·· .;
C>: l ... ; .. i
" '.I
! . '
"" ""
··I .. , .••.• I .
l ,t I• i -t .t 01
• i•
t:;::~::: .... ·~·::·_-'-_. :::::::::;:.:::::j;:::::::::.;:-:::::::::.:·::::::!1:~·~.-:i'.;.;:~·~•J..O:i·:..· f-1,-_-_-_t-_-...-_--T.J..I::+i---J..._J.' _-.._.~·----!::::::::::::~~.., ........ 5----~.,-,---l i " ! . . t f ~ r:: , .. ~~~~r-~--~~~--·~~--~~ --+---7-~~----~--------~~~·.~:l_-~,·~i--·~· ~·+'~·-'+·,1 _·~:--~:--~--·-· ------~~~ ;~ 10 ~·:~~l--~--·----·----;~l----~t--~·~·---~------------------------~~-·-·~!_:_.:_:. ___ i_·._:_._l ___ ·~ __ ·_;._:·_·~l------~-----------c.~~-r-~-~~~·,~-:--.--~,
., ••• o. ""'""---~'·"··~ --<-···--···-"·
~
-~-
0 0 0 0 0 0 0 0
0
0
\!1
0
Ill
\.f\
N
I
[
l
'
\ ··-"
[
f. L
'. \: ~
L
tf)
0
0
0 ,.....
z: -
400
300 . ~ . ' ' . . .;
•! I
. ' :f.
~ . . ; 1 r • 1 ... . I ,i ~ .. ~ t t ' : i I
' ! • ~ . I . l ~ i , t t t ~
FLOOD FREQUENCY CURVES
PRE .... PROJECT
• l.
'. ' ' • I •
'I I i 1 •"
l ~ •
I t I ~ I • J I • I I I
: I I • ~ I ' I t
-·---;-;:::-
' .
• . ..
1 I ' I i ~
I > I i • I I ~ I I. 1 ~ t : . ' I · : I i j • t t ! i ! I i I 1 Ill, I I
-
:.=::: -== == = --= -
·-
200~·~·-·~·~·~·~~~·~·~·~·~·~·~·r-·~·~·~·~~~~~~;l~i~~~~~~·~l~~---h·~·~·~~~~~~~~~~~~~-----~
t I t i f •• t ~ t I • I . I I t ' t I I : i ; t I -.--J I I • • . .; ... ' I ~ I { ! • i t ' ~
90
80
70
60
50
40
30
j I l i ! I I ! ! ' I I. l I I I I i I I •.• ! ~ ; ; ' I I i ' '.; I I I I 1 q I I i
I I 1 ! ! I : 1 . I l I ! i I ' i I I l ! T I ! ; I T: j I j ! i I i I : i ! : : l I I .! ' l L~.l_L _ __,;
l I I I I ! ! I i I : I ! I I ! ! : I i I I l I ;l I I • I I I I I I l I i I l l I . I l I
ii)l liil :t!l II+! ljl! !Iii l!lllill I I ll!i li I I~ GOLD CREEK
II II !Ill i I j I lltl ! Ill ! Ill i!1 l If I I I I i 1111 li i I ../" I ~l+l+!~l~i~'l~l~!+ir!l~l+l~l~l ~~~'+l~i~l~l~i~l+l~l~ll~!l~l~t~i~l~l_l~~-+'--~l~l~i~I~·~~.~;~~IDEVIL CANYON
1 ' 1 1 ! i 1 1 1 1 11 11 i 1 1 i 1 1 1 i , 1 1 ; , : i n 1 1 ! T 1 1 : i_ ./~ .J..-n 'J wA 'TANA
llllllll!llllll: llll llli l:illllil IIi! ,...,.....v;il.l~; 1~1 A
'
' f ; ...
'. f
J. 'i;
t I •
• I ~
I' . I
' I • ~ I I f '
I t• I
I, I I o • I
' I ~ j
' , . l I I ' I I,
'1
'.
.. '
'!I
I ] l' '. I' I
' I ..
·=
--
.:::
, I
i ! I I I i 1 I • I I I;!: I 1 •• 1 : .,., I: I i l l ' • 'I' ! ! .
I i • ; j 'II
• t • I;
t. . J :' I I
I l i . I i l . I'; iII: i: I! I I j ':.!I: ll! I l • I
': 1 ~--~+-~~~~~~~-+~~~~~~
l o~~~-l-·~·M'-'~l~ __ ;_;~'~l~l~i~·-·~~-:~'~·~'~~·-;~··~~-:_!~l~~-'--!-'~~-----i~·-'~-~~·-·-·~~~~~~\-·~--~---J
2 5 1 0 20 50 100 200 500
RETURN PERIOD (YRS)
-"'"-..~"''""'" ...... ·-·~·""""-·"~-·----·-~ ~-"-. -.
I~ F ! [
ZZ'l.\
r '-~ 2220
I' 'l.'l.'jCJ ~ .. ~·"'
.-.=-,·~
I
• ..l
(' 'l2.15 -
~ .. J
r\ '
~.J
~~ ... ...)
{'
rw
70
l~,
-.. .. .....1
-'--t--
. l .J
I .,
.. .
..
' ~" ,
'
::
~-iF
'". ~'
-~: ~:
..
. -+--~-· r:· t)
--= ~-
--,, ~3 . -.··
...
-!r .
-,---/·
-1
I ·::k:
ii .: ~ -~·
i ...
-t •• . . .. ~
" c !l )!
,.....____...,
I I k-iiik#Ni @¥!# . . i
:1 I ! ~Eli: · xpbP\EJQ wg;_4.k4&Ft2t61 i i I I .
·.. 1·1 : I \ofn I ~s .. a o.ffi I i ! . I i 1 I i I : I ! I
I "
~ . 222.0
;:
, .. .
" T ""
!
$
A~ ~t= :::. ~~?..=h s--r_._
. .
~~.::f=3.NS:~\-f'f7:---
·-=-j .. -+--
---+==j
-
~.'
\~AT ANA SP I LLHAY.£
FLOOD FLOWS ~FT3/S)
R.EJU Et~ 2ER I OD COST
t-ACILITY 1:100 1:10)000 PMF .MILLION $
CASCADE ALLC 1) 120)000 120)000 264
HB ALL(1) 30)000 30)000 50
FLIP 90)000 90)000 130
EMERGENCY 150)000 47
I ENVIRONMENTAL CONSIDERATIONS
DESIGN CONSIDERATIONS
Cl) EXCEPT FOR FLOW THROUGH POWERHOUSE
-
I. n
, i I
i ; i I \-
.·'1·.·1 n
l l i u
·J: n
·~ t.J
.1.1 n
FACILITY
STILLING BASIN
FLIP
DEVIL CANYON SPILLHAYS
FLOOD FLOW CFT3/S)
RETURN PERIOD
0 90JOOO
~ I,
, u HB
I n
0
ALLCl)
.. ' I ILJ
. ~ l""\ I t j
I u
.. ~1·.' I '
"'I t l
i -....,;J
1·.·_. ,,.,.,,....
~ r
\ l
I i i
l l
'l...,..-.l
I n I~
1 .. :
'l ~
·~· rl
~ \ }
I '""'
w
lu
Ef1ERGENCY
ENVIRONMENTAL CONSIDERATIONS
DESIGN CONSIDERATIONS
Cl) EXCEPT FOR FLOW THROUGH POWERHOUSE
,.,_we;
COST
PMF f~I LLION $
90JOOO 85
90JOOO 47
50JOOO COMf1j0N
160JOOO 25
I
I
I
.I
I
ALASKA POWER AUTHORITY
SUSITNA HYDROELECTRIC PROJECT
External Review Board Meeting No. #3
MINUTES OF MEETING HELD ON
October 6 -8, 1981, BUFFALO, NEW YORK
~ Presentation on: Power Developments -J~ Hayden
P5700.13
.I
I
I
1,~
'
I
I
-::
16 --------------
IS
14
13
12
II
L.EGENO
HES M GH : HIGH ECONOMIC GROWTH i-HIGH GOVERNMENT EXPENDITURE
MES"' GM : MODERATe: ECONOMIC GR<.iwiH + iwiOOERA'l"'E GCv'ERN"I't'i6ff EXP~NOlTURE
t.ES • Gt.. : t.OW ECONOMIC G~OWTH + t.OW GOVERNMENT EXPE~OlTURe.;
l.ES • Gt. AOJUSTEI:I -: LOW ECONOMIC GROWTH +!..OW GOVERNMENT
EXPENDITURE i-I..OAO MANAGEMENT ANO CONSERVATION
I
I
I
I
I
I
I
I
I
I
IHES • GH
I
I
I
I
I
I
I
I
~ 10 ~--------------------~--------------------~~~-----------------1 (.!:) -I
I
.,., _,.,.
...,-___.
_,.. __. L.ES -Gt.
AOJUSTEO
o~--------------------~---------~----------~----------~--------~ 1980 1985 199Q 1995
YEAR
2000 2005 2010
ENERGY FORECASTS USED FOR GENERATION PLANNING STUDIES
f) -
4 4
I
I.
I
.I
I
I
I N
I c z:
< :::::
IJ.J
c
I >-
t.!'
c:::
IJ.J
I z:
IJ.J
>-
-'
'I
::::
1-z
0 ---
I
10" 9
9.8 ~10
9.5
8.7 .. .
8.7 . 8.2
7o6 ~
7.6 7.6
6.5
7.0 7.0
"'" 6.7 6.6
5.4
4.3 -'
3 .. 3 ~
2.2 •
1 • 1 ~
0.0 JAN FEB MAR APR MAY JUN . JUl. AUG SEP OCT
MONTH
FORECAST MONTHLY ENERGY DEMAND
REF: WOOOWARO Ct.:tOE CONSULTANTS,
• FORECAS11NG PEAK ELECTRIC
OEMANO FOR ALASKA'S RAlLBEI.J".,
-
1 1
1 0
-.
.
NCN OEC
,~ r ., /-.¥ . _,___
~'> .. ~·
es~P~~aLJ~~~~~--~~~~~~
ENERGY DEMAND (GWH)
MEDIUM FORECAST
DEf·1AND <YEAR) POTENTIAL GENERATION <AVERAGE)
~!AT ANA \4ATANA
& & B.c. D.C.
1993 2000 2020 HI TUNNEL tiiTH TUNNEL
JAN 484 655 911 607 612
FEB 422 564 784 577 609
MAR 420 571 793 516 521
I APR 362 490 685 455 468
MAY 335 Lf60 638 425 430
JUN 310 428 599 407 420
JUL 309 422 592 478 483
AUG 326 447 623 727 729
-.;~ SEP 343 467 655 682 695
OCT 410 558 777 528 533
NOV 466 633 881 607 621
.. DEC 526 714 998 E62 6E5
;"' ·~
o · I , 1
r'·:
t ,, t
i
"\
"
o'mrt
. -'
Y. ·~ ...
e~~~~~~~·j•~~~~~~~-~~-
YEAR PEAK DEMAND
1993 860
2000 1 ... 173
2010 1 ... 635
20LJQ (EST) 4 ... 443
2010(1) 2 ... 901
2010(2) 1.,855
(1) HIGH LOAD FORECAST
(2) LOAD FACTOR OF 55%
(3) BASE LOADED
C4) WITH DEVIL CANYON ON-LINE
POWER REQUIREMENT <MW)
DECEf1BER
SMALLHYDRO THERMAL (3 ) . SUS III~
144 ·1Lt9 567
1114 LJ03/0(Lf) 626/1029(4)
144 372 1_,119
144 2_,676 1 ... 623
144 1 ... 422 1.~335
144 372 1.,339
I
I
. I
I
I
~·
I
I
•: •
I
I
t
'(
['
·~
II
[
f1
EXAMPLE CALCULATION
DECE~iBER 2010
DE~1AND
ENERGY CG\~H)
PEAK POV'/Ef< CMH)
ENERGY SUPPLY CGWH)
SMALL HYDRO
THERMAL
SusiTNA
Po~tER SuPPLY CM\~)
SMALL HYDRO
THERMAL(1)
SusrTNAC 2)
HAT ANA
DEVIL CANYON
(1) 100% LOAD FACTOR
MID RANGE FORECAST
998
59
277
662
144
372
1)119
750
450
(2) UsiNG 150 MW UNIT SrzE
HIGH RANGE FORECAST
1;779
2)901
59
1;058
662
144
1;422
1;335
900
450
I .
'\.
"
~~ r-::l ~ ~ ~ ~ . .J . . -----.•. '~~! --.---;,1
> • ' i. i } " • ~. f:_ __ J ~ ~e~F:f3llil~.L\r~~·':!··~-..LJi}!!-' ·-~~ lk4l ~~~e. {1litl
S(JMMARY COMP/\R I SON OF POWERHOUSES AT HATANA
. liEM
CIVIL HORKS
INTAKES
PENSTOCKS
PowERHousE/ DRAFT TuBE
SURGE CHAMBER
TRANSFORMER GALLERY
TAILRACE TUNNEL
TAILRACE PoRTAL
MAIN AccEss TuNNELS
SEcONDARY AccEss TuNNELS
MAIN AccEss SHAFT
AccEss TuNNEL PoRTAL
CABLE SHAFT
Bus TuNNEL/SHAFTS
FIRE PROTECTION HEAD TANK
MECHANICAL -FOR ABOVE ITEMS
ELECTRICAL -FOR ABOVE ITEMS
SWITCHYARD -ALL WORK
TOTAL
I
SURFACE
----.:;...:;;:;( $ OIJtJr-
4 X 210 MH
54;, 000
72~000
29., 600
NA
NA
NA
NA
I NA
NA
NA
NA
NA
NA
NA
54.~600
37.~400
14,900
262)500
UNDERGROUND ---..-( "r"P$0~0_...0 )~ ( $ 001]]
4 X 210 MW 6 X 1Lt011W.
54)000
22)'700
26.~300
4.~300
2"700
11)000
1}600 .
8)100 .
300
4}200
100
1.~500
1)000
400
55.~500
37)600
14~900
2146.~ 200
7oJqoo
28.~ 60r)
28.~100
4.~800
3)400
11)000
1)600
8_}100
300
4}200
100
1)500
.1)200
400
57.~200
41.~200
141900
277~000
Jill~.
1 • ' • : ··•~~' :II
""' \,. . .r: ·.~·.
I
-
~
I
I
f tl
Jl
ll
l]
JJ
.f'~
'f;:.,QI
r~
'Mil.
i}
[J
'~·-l
2300 J....-.---------+--------+--:r----------1
r-:r
\.!)
LJ.l
I
2 2200
~ ~
5.5 6.0
F\RM ENERGY C\000 GWhr)
,_.
I '-·-
1
I
I
I
1:\ ;,
<L;,.i
11
fl,
t.•
'
n
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u
l Ct
~.~ .. ~ t ' -
-> ...(;
$
f..!1
0
0
0 -.._, t,.O
)-
t!)
C!: w z w
~ 5.5
fY -
5.0
~
1-
1-
1-
~
~
~
!"
~
~
~
v
~
4.5'
/
I I
I -
.
/ .
/
.
5.0 5.5 ~-0
TOTAL SUS\TNA DEVELOPMENT COST CElLL. \9Bl ~1
-----····~-.-~, ......... -~-,-· ~--~ ···~~
. ., ~-' ' ;-',) ·,, ·-
I ~.~
I,
-i..,,....,.
I
I}
t..::;!;
u: l'!'l.i·
E
fl ;,
u
-t-Z300 1------+----------+----------+---------l u...
~
I
L') -w
I
~
L 2200 ~---+-----~-----+----+---------+----~ g
{] 2100
fl.
t..l
tJ
flg
t..J
TOTAL SUSITNA DEVELOPMENT COST (BlLL.l«iBl~)
-
I)
':_)
-. i , _ _,
I _:_j
1\ < ! L=J
1"1 l
d
(!
~
f,
~
J~ ~
f.
\-!
Jl ! r...,;;
fl 1-1
r1
J ~
r: .\
¥ ~
0
:r
~
\!)
~ rt. w
'l
I.!J
:t
~
1Z
bSOO
booo
5500
' . ' .
.v
lZS
.... ~
~ v
~
~ ("'"
z ·-
lf.O I(S
-
ALASKA POWER AUTHORITY
SUSITNA HYDROELECTRJC PROJECT
EXTERNAL REVIEW BOARD MEETING #3
OCTOBER 6-8~ 1981~ BUFFALO~ NY
Presentation on Watana Layout Studies -J. Lawrence
--
P5700.13
I
• . ,
·-· -. ~ ·~. \ -" . 11
% '
ill'lillllllllflii!DWIJUfiJIIII._li!IBI.IB~,_t!l.ll~ j~ 4~ •• L~ ~
-DAM:
o CREST:
o HEIGHT:
o VOLU~1E:
o SLOPES:
WATAHA LAYOUT -DSR
(JUNE .. 1981)
o COI-FERDAf1S:
-SPILL~~AY
o CAPACITY:
o TYPE:
o LOCATION:
-PO\·JER PLANT:
-DIVERSION:
EARTH/ROCI<FIL
EL. 2225 FT.
880 FT. ABOVE ROCK
63 MILLION CU. YDS.
2. 75H: IV U/S
2H: IV D/S
INTEGRAL
OGEE - 3 GATES
235,000 CFS <PMF)
CHUTE AND FLIP BUCKET
RIGHT BAHI<
800 MW (IJLT.), LEFT BANK
2 -35 FT. DIA. TUNNELS~ RIGHT EAMK
.(_.
r.:
. ;~
.,.
I
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.
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MAJOR DESIGN CONSIDERATI.ONS
-SEISMIC LOADING
-FLOOD HANDLING CAPABILITY
-EMBANKMENT DESIGN
-ARCH DAM DESIGN
-UNDERGROUND/FOUNDATION CONDITIONS
.
-REliCT CHANNEL
-RIVER CONDITIONS DOWNSTREAM
-ENVIRONMENTAL DISTURBANCE
-OPTIMUM SIZE & SCHEDULE
-AVAILABILITY OF MATERIALS
~ '•: o .. , • • ·~ ....... :, fl-' \~ ~l.t",:1~" •'' \,a;·. ,\'I:~: ',t.t ~,"','f. ~
. . . ,.. ., , ~ t \ .
-~~~~~~~~~~~~~~~~~~
tlATANA LAYOUT SELECTIOU PROCESS
r--~· .. ..."! • • ... ,. ... .... _ ... --..... .. • .. ..
ESTABLISH
PRELIMINARY
DESIGN
CRITERIA
.... . . ... .• . 'l
. I
l
I
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LAYOUTS . j1
' , ;I
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/
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.
ENGINEERING
L.~YOUT AND
COST
STUDIES
SCREEN t:l q PREFERRED I==
LAYOUTS
CRITERIA
TECH. FEI\S,
CONSTRUCTION
COr1PONENT SIZE
COST
ENV I RON~1EUTAL
OPERATING
REVISE
DESIGN
CRITERIA
EVALUATE ::::4 RECOMMENDED
PLAr-~s
CP.ITERIA I
TECH. FEAS.
COST
ENV I RONf1ENTAL
SCHEDULE
•
··. .! ~ I' ~· f· ?~\
til c . .)
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.. .,.
f:! DESIGN CONCERNS -~YITANA
-DAM FOUNDATION, SLOPES~ MATERIALS
~ J ' ' -DIVERSION TUNNEL PORTALS; COFFERDAM
FOUNDATION
-SPILL~IAY DESIGN CONCEPT~ CAPABILITY~
PERFORMANCE~ N2 SUPERSATURATION
I ~ -RESERVOIR LEVFL/FREEBOARD
. !
-LOW LEVEL RELEASES
-RELICT CHANNEL
-POWER DEVELOPMENT LOCATION/SIZE
-COST OPTIMIZATION
'c·'.•t;'''ii£:,::•. '-::;·::·~;,::~;· ,, ,:;..·:.:: .;._,.
-
.
'';\i
. " ' -~' . . . ~ /
1 -~ v
~~~~-~~~~~~~~~~~~~~
LEGEND:
A -2.5:1 U/SJ 2:1 DIS
\ B -2.25:1 U/SJ 2:1 D/S
L -LEFT BANK
R -RIGHT BANK
UN -UNDERGROUND
SU -SURFACE
S -SINGLE
D Mo DOUBLE
CH -CHUTE & FLIP BUCKET
CA -CASCADE
SB -STILLING BASIN
UC -UNLINED CHANNEL
• fj • "·! ~ . I
i
~ ~
9
I
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0
f'l"'. "' f'-1"\ 0') -.. - -Ci) 1'--i en t-i
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WATANA LAYOUT EVALUATIONS
STRUCTURE l1EI.ERI1lN8Il_ OBJECTIVE
DAM -C/L ALTERNATIVE 1 -REDUCE COST EASE CONGESTION
-DESIGN SECTION -TECH. FEASIBILITY
-STEEPEN U/S SLOPE -REDUCE COST~ EASE CONGESTION
DIVERSION -TNO TUNNELS -TECH. FEASIBILITY
-OPTIMIZE SIZE . -REDUCE COST
-RIGHT BANK -REDUCE COST/ACCESS
-INCORPORATE OUTLETS -ENVIRONMENTAL/FEASIBLE OPERATION
POWER FACILITIES -UNDERGROUND P/H -REDUCE COST/OPERATION
-LOCATE GOOD ROCK -TECH. FEASIBILITY (COST PENALTY)
SPILLWAY -SINGLE DISCHARGE UNACCEPTABLE -TECHa & ENVIR. FEASIBILITY
-SEPARATE E~1ERGENCY FAC I -TECH. FEASIBILITY (COST PENALTY)
-RIGHT BANK CHUTE/FLIP PREFERRED -REDUCE COST <ENVIRONMENTAL
PENALTY)
-EVALUATE LEFT BANK CASCADE -ENVIRONMENTAL BENEFITS (COST
PENALTY)
-~<:-!-
l-.::& ,;:;
FE 1:_
j
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C~.-. :C, .::: 1£.-::J ~1 ~ ~ ~~ ~ ~.:& ~ ·~
£REFERRED WATANA LAYQUIS
POWERp_LANI Er1ERG , SP I LLNAY SCHEME
NO. LOCATION TYPE LOCATION TYPE
\'I PI
WP2
WP3
WPLJ.
ALL SCHEMES:
L
L
L
R
UN
UN
UN
UN
R
R
uc
uc
MA I N SP I LUiAY__
LOCATION TYPE
R
R
R
L
CJ-1
SB
CH
CA
-DAM C/L ALT. l; 2.75H:lV U/SJ 2H: lV D/S SLOPES; SEPARATE COFFERDAMS.
-RIGHT BANK DIVERSION 2 -35 FT DIA. TUNNELS.
-INSTALLED CAPACITY 800 MW~ 4 UNITS~ 18 FT. DIA. PENSTOCKS~ 2 -30 FT DIA. TAILRACE
TUNNELS.
LEGEND:
L -LEFT BANK
R -RIGHT BANK
UN -UNDERGROUND
UC -UNLINED CHANNEL
CH -CHUTE & FLIP BUCKET
SB -STILLING BASIN
CA -CASCADE~ DOUBLE GATE
STRUCTURE
· ..
,,
I
~~-;
; !
I J
cc.'" . -.c>l
l
. r ., l
D
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j
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DSR
ESTABLIS~I
PRELIMINARY
. DESIGN
CRITERIA
l·lATANA LAYOUT SELlliJON PROCESS
r
-;.,.. --. ---·--··--·-· ~-·-·--·· .. . . • ... .. . ::::..-)'
ENGINEERING
L~YOUT AND
COST
STUDIES
--.·--.,, :1
. ... ·:
\ . I
REVISE
DESIGN
CRITERL~
8 ALTERNATIVE
LAYOUTS
-SCREEN 4 PREFERREDJ EVALUATE J
.-
(·:~ I CRITERIA I
I ... _ ... ~ ·-.. . -TECH. FE/\S, . ·-, I CONSTRUCTION
; COMPONENT SIZE
COST
ENVI ROH~~ENTAL
:; 10PERATING
.. '-" f-'. ....... i1 . ., . \ . ~ .. ..
I·' . \. •. \ ; ~· ... " ' 1. • • :.. .; •\ r'. · ·I\
~-"'"~~ __ ... __ _
LAYOUTS
:. I ,.. . . .. ,. . . ~,
,.. .. -..
CP.IIERIA
TECH. FEAS .
ICOST
'ENVI ROt·U~ENTAL
SCHEDULE
RECOMMENDED
PLANS
~ ~
0 • • • ' J ~ .. . .. • , -a ,...
y
9
~ _,,.
~ I
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<' IJ ·-~---/ ~
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ITEM
LAND & CLEARING
DIVERSION
r~AIN DA~1
f1AI N SPILLWAYS
Ef\1ERGENCY SPILL\~AY
POWER FACILITIES
ROADS & MISC.
SUBTOTAL
CAMP_, CONTINGENCY_, ETC.*
TOTAL
* CAMP & SUPPORT: 16%
CONTINGENCY: 20%
ENGINEERING/OWNER: 12.5%
PREFERRED WATANA LAYOUTS
~1Pl
53
101
1.,221
128
-
288
83
1.,874
1.,061
2.~935
COST COMPARISONS
MILLIONS OF DOLLARS (82)
\~P2 HP3
53 53
113 101
1_,201 1.,214
208 122
LJ7 47
288 288
83 83
WPLJ
53
103
1.~160
267
283
83 -----------------------
1.,993 1.~908 1}949
1.,128 1.~079 1,102
3_,121 2_,987 3.,051
,_,,
J
•~·-· IE:..~ r~-~ ~. ~ ~ ~· ~;:------~.---~ni-·•-";-~). ~-.--.--...;·~ f.~. • -·•~ C • • •~ ~ ~ !~ ~~ ,~ ~~ 1~2~ ~~ lL~ ~· k ...... J !,..., .. -4 . . ,_ .•. ,_1 \., •.•••. .,:> '--·-· w;:·:-;;}t tr*~ ~--~ '"" . . .· L--. ::;1 \,:":' , ..,..J.i ~~ ~~ -~·1 .,;'·'":-'!
STRUCTURE
DAf·1
DIVERSION
POWER FACILITIES
SPILLWAY
WATANA PREFERBED LAYOU~Y&LUATIONS
DETERMINATION
-OPTIMIZE C/L }
-STEEPEN U/S SLOPE
-LOWER COFFERDAM }
-OPTIMIZE ALIGNMENT
-T\~Jo LEVELS
-RIGHT BANK
-OPTIMIZE INSTALLATION
-OPTIMIZE TAILRACE ALIGNMENT
-RIGHT BANK CHUTE/FLIP
-RIGHT BANK EMERGENCY
-OPTIMIZE LEFT BANK CASCADE
QJ3J£CTIVE
REDUCE COST, EASE CONJESTION
EASE CONGESTION AT PORTALS
-FEASIBLE OUTLET DESIGN
-TECH. FEASIBILITY} COST
-REDUCE COST
-EASE CONGESTION
-REDUCE COSTJ ENVIRONMENTAL
PENALTY
-TECH. FEASIBILITY} COST
-POTENTIAL ENVIRONMENTAL
BENEFITS} MINIMIZE COST
PENALTY
0
.,..-1,
1
1
~).
t:•.(~~-~f .. ~~~~~~e~~~~~~~~~~~~A~~~~M~~
f DSR
ESTABLISH
PRELIMIHARY
DESIGN
CRITERIA
WAIANA LAYOUT SELECTION PROCESS
ENGINEERING
L~YOUT AND
COST
STUDIES
4 PREFERRED
.,.,._.,... ......... ---~--
. '
''
. ..
REVISE
DESIGN
CRITEHL~
I EVALUATE L 1----&
8 ALTERNATIVE I SCREEN I
LAYOUTS L/\ YOUTS 1 ;_.
CRITERIA
TECH. FE/\S.
CONSTRUCTION
COr1PONENT SIZE
COST
EUV I ROf~~~ENTAL
OPERATING I·
I
CRITERIA
TECH. FEAS.
COST
ENV I RONf~ENTAL
SCHEDULE
I. \, l : .
lL ~· .
'• •·. •• l ' .
' -'-
RECOMMENDED
PLAHS
I
, ..
' . .... ...,fo. .....
:~.:~ ~ ~· ...
----·.t~--···. ' ..
'-
ALASKA POWER AUTHORITY P5700.13
SUSITNA HYDROELECTRIC PROJECT J: External Review Boa·rd Meeting No* #3
MINUTES OF MEETING HELD ON
October 6 -8, 1981, BUFFALO, NEW YORK
Presentation on: Watana Low-Level Outlets -R. K. Ibbotson
~ ~. ~ ~~ ~~ ~z~
.•.
P.ERlOD · .
. .. CONSTRUCllON
' . i
fl.!!llillll.~
RESERVOIR FILLING
l Ji l
l
OPERATION
. :j
I
I :
'
.~ ~ ~· ~ r··~-::.~ .) >=P ~:~~ ... ~~~ ~ ~ .._) ;~ 1-.,J., :.li
HAT ANA.Jll'lERSl ON
F.UltCilDN Mf\x.._EUl\UCESl·
RIVER DIVERSION 76.,000
BYEPASS TO PROVIDE 10.,000 C.F,S.
DIS D 1 SCHARGES
EMERGENCY ·RESERVOIR .. . 3 0., 000 C a F • S •
DRAWDOWN ..
~ ,. ~
'-,. -""'·,:_.-'I'.,. ',(~·~· .. : · •• "!!•"• u • c ,; r: w co: w 0 ~ :r: .... .. ::1 . c -= .. ... ~ ~ ;; 2 ~ .. to .. a ~ ~ c :~ "' : < -... c .. . .. ... I ~ ~l -
2
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10 I P. J • I 7 J • I a ~ ~ . L _ .. 3 __ _ ' ..
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11100
1100 l
Fl
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1&00 -, 1700
tr.oo
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14;:10
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1'700
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1<400
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l
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tOo\M
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f I !I t
LEFT T~NNEL DURING DIVERSION-SUBME~GEO OUTLET (ALT.. I)
f Oo\lo\
I
f . '::· .:;.[_:::: '21 ·d
LEFT TUNNEL DURING DJV~IiSION-:tRE:~.OUILET (ALT. 2}
~rw;,
'
RIGHT TUNNEL DURING DIVERSION
7 t • • t
UOm.II\L RIWII,
W.L.145f
HOIIW.L I!IVI' ~w.~ .. l<45.11'1t.
0
,
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a
rm;;J ALASKA POWER AUTHor;:trv 1 "'
LAi~tJ.J 1Ut11"A tiYOfiOlLtCflltt , ... OJIC1
WATANA
DIVERSION PROFILES
I tAt1 r ... 1 ··~ I. ~lh.i ..... J...;ua:.':(;;;.;-.-:;o ....... u
• .----·--" _.! ----~--!-2
DIAMETER <2<t6~NELS)
25
30
35
liO
30
35
40
WATANA
DLVERSIOH TUNNELS
ECONOMIC DIAMETER OPTIMIZATJ.ON
~BESSUHE IUNNEL ..
TUNNEl COSTS
$ X 1000
COFFERDAM COSTS
$ ~1000 TOT~Ll~MD(l)
47~000 29.,500 . 76.,500
56.,000 10 .. 000 66.,000
66~500 3.,500 70.,000
83.,000 1.,500 ~, 8!1.,500
FREE FLOW TUNNEl
TUNNEL COSTS COFFERDAM COSTS TOTAL COSTs<l> <2>
$ X 10000 $ X 1000 $ X 1000
52.,000
63.,500
80.,000
17.,500
5:,500
2.,500
70.,000
69.,000
82.,500
(]}"f01iAl COSTS DO NOT INCLUDE INTAKE STRUCTURE AND GATES
OR OUTlET STRUCTURE. .
(2)TOTAl COSTS FOR FREE FLOW TUNNEL DO NOT INCLUDE ADDITIONAL
COSTrS FOR CLOSURE.
-
l
~~
1
10
c
15ro
1700
I tOO
t
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8 7 ~ • II • •
'"' · 'rs! In· 1 f ~~~ ,_... ···-·-r.., ... r~~~l·-
LEFT TUNNEL PERMANENT OPERATION -SUBMERGED OUTLET (ALT. II
/ ·· >1• C\..;:f--ct'"o
-~-------···----~-,I~ .. -..... _ ....... t DAM
LEFT TUNNEL PERMANENt. OPERATION-FRfE bUlLET !ALT. 2)
----·••-• u---·------
.~ """" .. --.:..
------· ~
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RIGHT TUNNEL PERMANENT OPERATION
.... , ..........
8 1 t • a t "
3 ~
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AlASkA POWER AUTHORITY A
2
-~SUI UNA. H•DIIOli.fCttUC PllfUICT
VI-UANA
DIVERSION I'I?OF'ILES
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SECTION J-J
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r~w~ ~ c~ f~
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EXPANSION CHAMBER QETAIL
\-1 ..
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;, ,
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SECTION G-G SECTION K·K
AlASKA POWn AUTHORITY
IVItU .. , t"tll
Wt>.fANA
LOW LEVEL OUtlET
-::;:f~:: ~":: :::: l·lli~~=--~~TAn.s 4 S£CTK>NS
: .,.._ ,. ,.,. "'• i(Jii-;t;,._.._J•al•,.•"-
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-·· 7
-s -,._. .. -,.·-., -' .... I --I -----:.~..:::::-.:
~100
2000
1900
1&00
1700
1600
t. 1500
1 .. 00
MAIN DAM PROFILE
SeAl-'' I.
1300
·u;:,o
1100
1000
1'100
1800
NC!tMl\.~I!.\Jt.1
·---------------------------· ~~~~--\.-~---L-~-L-12-~-·------~~1tr~~====~~-------------------------------------------------------
noo
IGoOO
1!100
... oo
I
4RWT tlllnt.tw.-1
I
MAIN DAM SECTION AT MAXIMUM HEIGHT
SCAI-C.r 1>.
~ r---------------------------~~-----------------------------------------------------------------~------
1100
(OLI.I
1600 't I ...... ~......... ~I I /\ ;yo:_ I"~· . I I ~ 1500
1<400 --.
SECTION THRU LEFT TUNNEL
.$Gtl.l..A.'" a
n.l4o40'
1!00
:I
~ ~·ccrn.Jtou.tll.l!.•o' -t--
• e!li.I:RETe. "'-"" .. -, ~-1?~11:---:~~~=---n=4l--•~-1
L.~~=~~~~; SECtiON THRU RIGHT TUNNEL (sc~u.•&)
1500
1400
~o·
1550 ....
1500 1 ..a.,. :&{5~
14501..:..~-
I•
. i r•o .. 1
W'l"EltOO.o.1 t !II.URRV 'mtNCII
r POCk Cit ~ .. 'lt\.• FILl.
~~ ··~·--
UPSTREAM COFFERDAM SECTION
'!loC:AL&.I C
!0-L.S."
<' = ~f'U.T
0 oOO ~I'EE't'
t.c:At.& e.
0 a.o 110 FEET
~\.t c:.l --~~----~
PLATE 0.2
[iii] ALASKA POWER AUTHORITY
IUUtiiA tl'l'fUftU.ICtltiC P"CUtct
WATANA
VALVE TYPE SPILLWA'f ALTERNATIVE
MAIN DAM AND DIVERSION
I I I I J,.. .. auoust. tte~ E RI>.L ~~~~·ot-t ..........
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----·--: ,_~:.?:1 [:i$~F['o~40' r~~ ·-· -:-,or· .. .. -·--~ ---·--~·:::--~----I 0
1
!200
2100
~000
1900
1600
1700
!(,00
1500
1400
.. J':.,·-,.
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~ ~£0:. ==---==·
MAIN DAM PROFILE
SeAL£'"-
NOIU.U.l. Ml.ltM.M
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uoo
tiOO
--------------------~~~----.•~~~-·-~-~_.·_~_i_t_1_2_~ ______ ~~~~~=====:-----------------------------------------------------·
2000
1900
1&00
~ 1700
... 00 ~
1!>00
1400
I
GRQJT CUI:m.t>l-4
I
MAIN DAM SECTION AT MAXIMUM HEIGHT
SCAUi.•...,
·~ r---------------------------~~----------------------------------------------------------------~-----
1100 1--------------·
tt06 r-;,·, !-" 'T'Nti3Git
1500
1400
..aoo
1100
1600
tSOO
tofOO
SECTION THRU LEFT TUNNEL
SGA.t.a.: D
. !CM1
~ ~ corn11ou.. f.I.IS~o· -~--·-·[-
4. cOI_~Pl~ '{ ~.'bdL-.-. ·:.--,:-.p,. --·. ::;) -~ '1 f.-· £i.,.;zo·-i!J I a.~lW)' :~:-::.-; •• ~r = __ --~· -1 --£~=~~T SECttON 1HRU RIGHT TUNNEL (~'-'·0>.> _____ .., .. ~ --· .... -.
CLI440'
:.o·
·~50r----
ROCK ~ Coll'-11£1... I'll.\.
1600 I _ ~....,L,f.l
14EC! ;y:;. r "il~~~ \\\ . 9~
t•
l/ ·----
·r-IG' •. i
iCOI"''l:S'.OO.M t :>l.UIIRY TAtlbl
%.0t"J&.!i.
UPSTREAM COFFERDAM SECTION
~CAL.&.• c
a.._..aE..~'-QE.vt~aOtoJ
"'"'"""'
~t..:S. ,..~f·~~~~-~
0 100 '1.:1:> 5iiiiiiiiiiiil FW'
lle.AI..ll!o'
0 GD llll ~Eti.T
&t~>l.t e l! =-.iiii
o. r ..... ...,
PLATE 8.2
AU.SKA POWER AUTHORIYY
eUtlt•A tlf'f&IOI\,IC1RIC PIIIOIICt
WATANA
VALVE TYPE SI>ILLWAY ALTERNATIVE
MAIN DAM ANO DIVERSION
F
£
....
I>
c
•
A
,,
j
:I
u
i}
~ I ..,.e•~, .. n 10 • t 8 I 7 t 6 ~ t .. lll t a
~ I -~ .,, ct. ~·,.~,.WJJA,J44!¥WN$AMC#Ai$.LZU.SAQJ.tU¥.£M#llCJ§tt&QUCWQ ... ,£·"'····· ili£-' •• 1,·1:.-~·11·•·.· ... ·.·j.J£4~--:i;a;· ···~·-.••.•. ,, .-.. -. -~. -_,,· f.l ··f . .,,, .: ':".-,. ~. ·l··l~'i .... ·B··.··.~r~··IIUJ .. -~§1 ~I: J ..-a.····: aB·~·...,·,..........·'OC· ~'";.J~~r~'~.·'-=~ ..
WATANA DIYERSION
PEAK INFLOW
50 YR RECURRENCE
PERIOD DESIGN FLOW
PEAK OUTFLOW
THROUGH DIVERSION
TUNNELS
TUNNEL DESCRIPTION
COFFE~~AM HEIGHT
83.,000 CFS
•
76.,000 CFS
2-35 FT CONCRETE
LINED TUNNELS
90 FT-CREST EL 1540 .
CONVERTING ONE TUNNEL TO A LOW LEVEL OUTLET WITH AN
EXPANSION CHA~BER FOR ENERGY DISSIPATION.
OUTFLOW WITH RESERVOIR a EL 2020 (550' HEAD)-30.,000 CFS
OUTFLOW WITH RESERVOIR D EL 1600 (125' HEAD)-15.,000 CFS
OUTFLOW WITH RESERVOIR a EL 1550 <75! HEAD> -11.,000 CFS
" _i< • : • !; ~ : .. .~~~;. ..... ~
" ' 1<
• •
~ l::~~'fj
G
,
' ~ ~I ,·
i .,
1 I
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l
fl'lll• "lW!iiiii\~
i
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~~ If¢ .. ·"* .. ~.__..--_ _,..
if'
/
I
l
....,... ............. t4! tOo
r.~-~ r"·-~ r~~ --... --~ ~-1 _ .... -..J ....
[~ . --1 f~ ~~ l_ . .J C,J
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. =:· ..... I . I
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r...-~ L j
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----· ---·--.. -. . . ..
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[.-....,. r _-:a c-:-J [ "1 r· . -[ .. ~ J [_ ~--] [ ~-J '·. _, .11 l ·.-" j I. -
~~~
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A I ll ~ I.
Cl
F
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/ /~3<//~ 10
--------.
c
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A
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it -.. ·1
h~ :,.
--·.;;; ..
ALASKA POWER AUTHORITY
SUSITNA HYDROELECTRIC PROJECT
External Review Board Meeting Noo #3
MINUTES OF MEETING HELD ON
October 6 -8, 19~1, tiUFFALO, NEW YORK
P5700.13
Presentation on: Devil Canyon Low-Level Outlets -R. K. Ibbotson
DI~ER
<2 tfiN~ELS>
20
25
. 30
DEVIL CANYON
DIVERSION TUNNELS
ECONOMIC DIAMETER OP]IMJZATION
PRESSURE TUNNEl
TUNNEL CfJSTS
$ X 1.000
19~8IDO
19.,000
23~0([)0
COFFERDAMt COSTS, TOTA$LXCOSTs<l>
$ ~· 10001 1000
]01500 30.,300
1.,500 20.,500
800 23.,800
SUBSEQUENT TO OPTlMJZATJON 1-35 1 DIAMETER TUNNEL WA~
-INVESTIGATED AND FOUND TO BE ADVANTAG.EOUS OVER 2-2~
D·IAMETER TUNNEL.
35 14.,000 1.,500 15.,500
{}) TOTAL COSTS DO NOT INCLUDE COST OF INTAKE STRUCTURE OR
GATES AND OUTLET STRUCTURE. ·
11
L'::i"
DEVIL CAnYON ElVERSION
PEAK lNFlOWI
. 50 YR. RE£URRENCE .
PERIOD DESDG~ FlOOD
ROUTED THROUG.Hi WATAN-A
PEAK OUTFLOW
THROI!GH DJVERS I ON~
TUi~NELS
l~NNEL DESCRFPiiO~
COFFERDAM· HEIGH~
52.,000 CFS
0 •
52.,000 CFS
1-35 FT CONCRETE
LINED TUNNEL
50 FT-CREST El 950
r
[
[
r
f·~
' ,;·
r
'I
.,
··"
t~
f I ;,
J ••
I
k;;:-
DEVIL CAUYON ElVERSION
PEAK INFlOW
50 YR. RE£URRENCE
PERIOD DESDG~ F.lOOD
ROUTED THROUGHi WATANA
PEAK OUTFLOW
THROUGH DIVERSION~
TUi~NELS
liUNNEl DESCRI:PliiOrt
COFFERDAM' HEIGH1
52.,000 CFS . .
52.,000 CFS
1-35 FT CONCRETE
LINED TUNNEL
50 FT-CREST El 950
r 1.,\) r· ..
[ . --:1 .. ,
L ·~
[ .
I 1
r~·
. '"·····-; •·! '-.' ,I \~ -•
..
, ..
VR._
-.
- -. tO
•
8 ..
i
!
I
I .
1
I I .
!
ALASKA POWER AUTHORITY
SUSITNA HYDROELECTRIC PROJECT
External Review Board Meeting No. #3
MINUTES OF MEETING HELD ON
October 6 -8, 1981, BUFFALO, NEW YORK
Presentation on: Devil Canyon Dam Design -R. K. Ibbotson
P5700.13
';~ '":---. 0 ... .. ! i • s ~ : l ~ ~ t ... ~) 1COU.'I/IS,I
·-... ~ & .. : :! ~ ~ I '1: : ! ..
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MAJERJAL PROPERTIES
A) CONCRETE
FROST RESISTANCE CONCRETE STRENGTH (Jv5 DAY)
UNIT WEIGHT
STATIC MoDuLus oF ELASTICITY (susTAINED)
DYNAMIC MODULUS OF ELASTICITY (INSTANTANEOUS)
PoissoNs RATIO
TENSILE STRENGTH!
STATIC (FOR EST!MATtDNG CRACKING ONLY) 5% OF
STRENGTH
DYNAMIC FLEXURAL ]5% OF STRENGTH
THERMAL PROPERTIES:
CONDUCTIVITY
SPECIFIC HEAT
COEFFICIENT OF THERMAL ExPANSION
DIFFUSIVITY
s) FouNDATION RocK
DEFORMATION MoDuLuS (susTAINED)
Po1ssoNs RATIO
-
5.,000 PSI
150 LBIFr3
3 X lQC PSI
5 X 106 PSI
0.2
250 PSI
750 PSI
1.52 BTUIFTIHR/°F
0.22 BTU/LB/oF
s.E x Io-E FTIFr/0
Oa04E FT2/HR
2 X 10E PSI
·0.2
'':"'' '
;:) '· ', :z ,(;.-,~ ··;~
,,~ TEMPERATURES. (0 E)
.... i (BASED ON AVERAGE BETWEEN· SUMM~'Ti AND: TJ.\lKEETNA)
ll AIR TEMPERATURE:
MEAN ANNUAL
HIGH.~EAN Mo~liHlV
Low MEAN MoNTHLY
28.9
55.0
4.4
RESERVOIR HATER TEMPERATURE
.
DEPTH BELOW M 0 · N T H 8 SuRFACt:. lFT) 4 5 E 7 Q -·
0 -50 32 32 LJ6 57 53 45
70 TO RESER-
voiR BoTTOM 39 39 39 39 39 39
'
JlO 11
39 32
39 39
GROUTING TEMPERATURE OF VERTICAl., CONSTRUCTDOfll JOINTS! 39oF
12 1 2 3
32 32 32 32
39 39 39 39
u
· C0~1BINATION CLASS U S U A L
LOAD C0~1BINATION C0~1BlNATION NU~1BER UL-1 UL-2 UL-3 UL-4
UNUSUAL EXTREME
UNL-1 EL-l EL-2 -···---------------------------
B S
A T
S A
T
I . I
c c
L
l 0
DEAD LOAD X X X X X X X
-~ -:~ AIR & RESE~OIR FEB. ' X
n
\·lATER TEr·1PERATURES APR. l I
l \
~
! X
,!
I l I
tl
.J
~
RESERVOIR viATER l~lJ45 . \ X X X X
0 ~ · LEVELS _
A
LQ55 . I ~ X X ~ l l 2~5 X ... r------l \
D
c
A
s
E
s
s
D
y
N
A
M
I
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L
0
A
D s
MAX 1~1Uf.1
CREDIBLE
r
J' 0.5 G
. ~~ 5% DA~tP
.
·1
I
EARTHQUAKE 0.46
10 DAf1P.
I
1
1
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I ,.
o!
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'
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J
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' ' II • I
X
X
...............
-
I
0
0
. '
EX1Tf1f sm:m
AT OOCK/COOOf IE INTEifACE
l..cM\DING ~!NATION (SlKESSES IN PSI)
fmTILEVER
f"Ax
ll-1
7:!2 (D. El lJ.OO)
23 <U. El IDlJ)
7l2 (D. El 820)
MIN -'11 <D. El1370) .. ~
-INDICATES 1ENSIOO .
D ~~mtCATEs· ~~ FACE
U INDICATES UPSTREAM FACE
tl\Xltlll SIT£~
• I
trotE. FOJliDiiHJJ
PRa;
rwc
MIN
"""
CNITI i.EvER
rwc
MIN
-
tl-1
958 (U. ElllOO> ~
182 (D. E1 IDlJ)
575 <D I EJ. ])I))
0' <D. Ell455)
EXIlEf srr£m
AI OOCK,/crnrn: IE INIEifA!E
lcwliNG UJ.BINATIOO (STRESSES IN PSI)
Jm.t
ft\\x
MIN
fANTILEVER
f"Ax
MIN
-INDICA1ES TENSIOO .
D I~kHciTEs·WnNSTfB\"t FACE
U INDICATES UPSTRE.AM FACE
ARo-t
~
MIN
Cwfii.fvER
ft\\x
MIN
r1\Xltu1 Sl ffS;ES
• I NINE. fQt1IDi[l(lJ
-
ll-1
lJ2 <D. El 1100)
23 <U. El lflD)
m m. El SLU)
-27 <D. 8.1370) .. ~
ll-1
958 ( u. El 1100) fO!f--
182 <D. El Jim)
575 (D I EJ. J.Ca))
0' CD. E11455)
"
I
:__;;
I
DEVIl 'S CANYON ARCH 0.~
ARCH STRESSES P~Rit.lEl TO TttE FACE I:F THE DAM
LOOKING UPSTREAM
l~a Hydrostntie 6 Grnvity
nrv s.JA 1714.71 171tt9'9-1~38.59 152·6.JS 1)9) .. 57 1259.68 1taJ.~Ii UXRJ.OO · 812" .. 66 7SJ .. 95 61~.59 ~04.24 n4.12 '461.~6 4!t4. 76
~ -~
TAU 12.
14SS. [ 267. 274ec }0) .. J24.
417.
406.
4JB.
484.
J66.
516.
J07.
467.
J1J.
J86 ..
41Z.
-zu.
}71. J4~. }11. 3~4. 479. ~01.
1 607. !t16. '~2. -~46. 462. c\46. .}99. ;jQ. ~8).
t•U 11. -2. TAU
1l70. E 110. 206. 29~. 416. S9J. · 707.. 642. 405. J~S. .504. 282. 277. 261.
I J1b.-!11_ __________ ..,_;-........·.:..· __ ..;.·-·-----~~.;.;;..98. s1o. J96.. z>a:. 2ss. •~s;l ~o. . ~ S42o li10. 378. --
TAU 76. 71. Tim
1285. [ 114. 2J7. J92. 621. 822.. 199. 449. 362. ·281. 2JJec 271.
.. ----------:..1 __ ._..,;4~'.:.'=-· _ _..::;.~.::;.::58::,:• _ __:5:.;::8:.:..7.:..• _ __;;:~.!:.,6 7~·:.:.· __ 2::.:6:.:2:.:..• _ __,:2:.::,5:::..:9 ·~_.;:;.5::,21.::..::·~ 592. 622. ill! S4S ..
TAU 162. 14~. TAU
1200. £ 174. 298. 562. 851. 919. 481. 3~1. 230. 171.
I 602. 654. 540. 319. 266. 590. 674. 74J. 7!J9.
1100.
Tltl 260. f~ . ~;_. 210. TAU
E 177. 372. 744. • 958. 4JO. ZJ1, 106.,
1 704. 620o 3~7. 244.. 609,. 121. 792. il'~ _...
TAU 292. 227. TAU
1000. E 110. S17. 07J •. .,. 2SO. 2,. ~
1 708. •21. ~.:-1oo182.v SJ2. 665. ~
.t'\..../'
~;
f
t
EXTREME S.TRESSES
AT RQCK/CONCREIE !NIEREA£E
(STRESSES IN P.S.!&)
LoADING CoMBJNAimoM
ARCH·
MAX
MIN
CANTILEVER
MAX
MIN
Ul-3 (POINT)
747 <E EL 900)
~182 <E El 1455)
689 (Dl EI!. 820·)1
~ 393 CD a 1370) ~~ -----------------------------
ARCH
MAX
MIN .
CANTILEVER
f1AX
MIN
tiltX I MUtr STRESSES;.
ABOVE FOUNDAJIIOtt
LOADING (OMBJNATEOM
-
UL-3 (POINT)
11so <E a uoo>
-134 (J El 1000)
CE EL 1455>
515 CU El 91J0)
-75 CD El 1370)
C"'-:--.;; t~~ ~~ ~ -~ ~ -·~-·, ~ ~:~
.j ::1
{\ MY 1L • S CANYON ARCH DAM LOID.t Hydrrmtntic A Gravity
llli fol'lll A Linc1r let!llperature
..
CANTILEVER STRESst:i PARft.LEl TO THE rACE (f" THE OAH
lfAJ<ING li'STREAH
IT£V STill 171tr;,99 16)8.58 1526.)5 1)9).57 1259.00 1143.68 1000.00 81i.o6 753.95 _&19:$9 :_60lJ"~ -·~524.ll ___ &61,)6
TAU 0. o.
1455. u o. o. o. o. o. o. o. o. o. o. o. o. o.
0 0. o. n_ n_ ~· -· -· Oo fJ•.._, 0, .. 0. ·-_ Oe __ 0,___ _0. ac __ 0 •.. === ......... 0!.
TAU 49.
1.170. u -~ 48~."'" 192. 166, 14J. • ..... .j 0 ~ -J9J.< -60. -24. 10.
.... ,,.,,~
. ··-'·j TAU OJ.
"' 128~. u 287. 2J4. 214.
146. 140. 126.
16. 2 6 • =t=:r:=· 41.
210. 201. 172. I I 0 -4 7. JO. 70.
' TAU 195.
as .• 110. 1!11. -
1200. u 21.1. 244, 2.18. 2J7. 192.
D 177. 158. 191. 218. :l19.
"'): ! . TAU '28. I 1100a u 22~. 2~1. 287. 2~5. ',2; l
D '''· .H2 .. 318. 382.
TAU 407.
10u0o . u 252. .3~1. 384.
. ::.~ I D 555. 401. *'00.
TAU -'89.
9UO. U 403. ~15.
'~.
]
-====1::1:7.:/1--=~ D ~94. J9J.
a to. TAU u
0
1J9.
JJ4.
689.
141.
15.
210.
89.
256,
161.
J71.
186.
~61.
1JO.
2JO.
679.
201.
u u;:t 4 °
(.\
IJIII.II4W L-·'" · -'~ --·~,,--."-. -··~-.. ~h--. ·I· '"Jl.·.~~ ':'c,al•·'·~ '*wtueasz ;azaa J41tw. -~ ......,.. . '"'. ~. \.. :________i > ,... >> -HE
150.
8.
229.
58.
JOJ.
90.
422.
105.
265.
496.
198.
TAU
1~6.
-4.
258.
11.
351\.
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225.
415.
90.
Y~U
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28J.
-J7.
156.
J16.
29.
TAU
.H.
208. I 4)4.
-7~. -J29.
87 • TAU
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-99. -
TAU
TAU
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!·~ ~ "'"·-""~ c:--"' -"""""":;. r· -~ ,---; ~ c "'Q ~· .. -. .._. ,...., -""'"' ·~-= • ~ ...,_"""1 -.-.,.., * ". ., --!! 4 m:
DYNAMIC ANALYSIS·-CANTILEVER StRESSES (Pst)
EARTHQUAKE J.\CTING UPSTP.EAM ---------------·~· .. ·-··· -·-~
O,SG GROUND ACC'N .. 5% DAMPING
CROWN CANTILEVER
ELEVATION
....... ~~ --------
llJ55
1370
1285
1200
1100
1000
900
820
U -UPSTREAM
D -DOWNSTREAM
FACE
u
D
u
. D
u
D
u
D
u
D
u
D
u
D
u
D
STRESS
0
0
-581
653
-729 ..... ~~
1021
-629
1111
-435
1110
-142
1026
-19
928
-402
15ql
• IS&P*b w ••. d ,··~· , t .. ·. IZU n usux;;;,a;;ms.{. LAJJ44fc. uwrm;;z ;az . .t: as:; AitSJ&MILJ#Cl.I&UkCMUJSU&40PAILKUU,W!Ilti ZliMM-S&t!CJilll££121!llll12111 Ill': . ' ~-:-::tf~h "l!'-:1""-'",rj«~..,-0"~"1'~"'"""~,...., _....../ • .
:1:' '.
.
EL. 1455 FT
FACE
E
I
El. 1370 FT
E
I
E -EXTRADOS
I -INTRADOS
;_ : -· ":;~ '--:' "' ., .::;=-· '31 ~ --....-..,..,
DYNAf1IC /\flALYSIS -ARCH STRESSES (Psi)
EARTfiQUAKE ACliNG UPSTREA~
..... ..... -··~-""~·---
O.SG GROUNO ACC'tl .. 5% DAMPING
STATlON
1714 1711 1526 1259 1000
25711 2513 2033 2948 3404
2478 2409 2566 2749 1943
1220 1188 2461 3657
}qqq 2383 22q7 949
1 ,} l
'•r.
. ·,\ ~
\-' ,.. -,. .....
....
~)
, nsr.t.ti!l~ •
I
}
!":~-~ r~ ~~~ ~ ,..,_~ ~-~: ~-~ :. ~
DYNAMIC ANALYSIS -CANTILEVER STRESSES (PSI)
EARTHQUAKE ACTING DOWNSTREAM
' -" ....
O.SG GROUND ACC'N -5% DAMPING
CROWN CANTilEVER . . ...
ELEVATIOU FACE STRESS
.. ·-
ll155 u 0
D 0
1370 u 799
D -561 a,.!c·=~
1285 u 925
D -577
1200 u 711
D -307
1100 u 639
j D -22
lOOfJ u 638
D 124
900 u 785 .
D 90
820 u 1012
D -97
U • UPSTREAM .
D -DOWNSTREAM
·~~-· ~ ::c~ ~~
• '": 1
.,: t
. . . • .. j ·~ Jc ·. 'lfL ... ,...~,. "'lb$44Ubil4t!Ni* :.St.Q¥tPJ>.«< llh.S:WlACL&SC:ltli®t 44WMZSJQLQQ£2WA·Zttu£tti0k£JQJCWSi.l9JIIIIIIPIK£122 .#CC ill K&es ·
-· -... -....... -_,. -,.
,(-' '
.-:;;;
~"
,•
.~ '.
',' c-"'
'"
(
~:"t ._.,~ ~ «,_• ~I Jr':-::;:..~ ~ ~--:~ ~· , . r~,-~--. ~-,~--~-~
EL. 1LJ45 FT
FACE
E
I
El, 1370 Ff
E
I
E -EXTRADOS
I .a INTRADOS
DYNAMIC ANALYSIS -ARCP. STRESSES (Psi)
EARTHQUAKE ACTING DOHNSTREA~1
0. SG GROUND ACC' N -5% DAt;1P I NG
STATION
1714 1711 1526
·2040 -1965 -1385
-1267 -1257 -1732
1259 1000
-19RO -2470
-2017 -1630
-1000 -598 . -1275 -2373
-701 -1387 ) -1455 -lf39
,,
--•,(J
~
. .._
·;;:!
EARTHQUAKE ~ht~AU~~ OF
0.5G 1LJ55
5% DN·1P 1370
~ -$;:_-=; --~ . ' -! ••• ~ ~-..~.~"at7'"'"· • ~ •
I U O!L!G 1qss
l,fi._
(
F :)
I
10% DAr1P 1370
~ I . 1,( l
',/
c)
.~)
f)
J·
I'> c' ~-~\fl" ~~ ~~ """'"'''•
). •.• b ·J t,; J l 4
DYNA~1IC ANALYSIS -ARCH STRESSES (psJ)
E~~RTHQUAKE ACTING DONN STREAM
S'o"'hv.o·
STATION
.,. ..
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ALASKA POWER AUTHORITY
SUSITNA HYDROELECTRIC PROJECT
EXTERNAL REVIEW BOARD MEETING #3
OCTOBER 6-8, 1981, BUFFALO, NY
Presentation on Devil Canyon Layout Studies -J. Lawrence
-
P5700.13
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-DAM:
o CREST:
o HEIGHT:
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-AUXILIARY SPILLWAY:
o CAPACITY:
o TYPE:
o LOCATION:
-EMERGENCY SPILLWAY:
o CAPACITY:
o TYPE:
o LOCATION:
-PO~IER PLANT:
-DIVERSION:
IlEYl.LC.ANYON LAYOUT -DSR
JUNE, 1981)
THIN ARCH/EARTHFILL SADDLE <LEFT>
EL. 1460 FT.
650 FT.
OGEE - 3 GATES
90)000 CFS
CHUTE AND FLIP BUCKET
RIGHT BANK
ORIFICE -3 GATES
40)000 CFS
CONC. LINED PLUNGE POOL
THRU DAM (15' X 15')
FUSE PLUG
lOOJOOO ffS MAX.
UNLINED CHANNEL
LEFT BANK
400 MWJ RIGHT BANK, UNDERGROUND
2 -26 FT. DIA. TUNNELS LEFT BANK)
EARTH/ROCKF ILL COFFERDAf1S
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M8JOR DESIGN CONSIDERATID~
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-FLOOD HANDLING CAPABILITY
-EMBANKMENT DESIGN
-ARCH DAM DESIGN .
-UNDERGROUND/FOUNDATION CONDITIONS
I -RELICT CHANNEL
-RIVER CONDITIONS DOWNSTREAM
-ENVIRONMENTAL DISTURBANCE
-OPTIMUM SIZE & SCHEDULE
-AVAILABILITY OF M,ATERlALS
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~lL CANYON L8YOlJT SELECTIQN_YBOCESS
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L~ YOUT Al··JD
COST
STUDIES
REVISE
DESIGN
CRITERIA
I I DSR ! : 3 ALTERNATIVE I SC&JN 2 PREFERRED I EVALUATE '
LAYOUTS I LAYOUTS l
RECO~MENDED
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CPIIERIA
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DESIGN CONCERNS -DEVIL CANYON
-DA~1 DESIGN., SEISr1IC CONDITIOrJS
-ABUTfvlENT AND FOUNDATION IN;fEGRITY
-SP I LLWftY DESIGN CONCEPT.~ CAP/\BI LITY 1
PERFOR~1ANCE.~ N2 SlJPERSATURtATION
-POTENTIAL SCOUR CLOSE TO DAN I . .JfJ
-RESERVOIR LEVEL/FREEBOARD [ I , I 11
-L0\'1 LEVEL RELEASES . I
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(\ --SADDLE DAM MAtERIALS/FOUNDATION
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-PO\·JER DEVELOPMENT LOCA.i ION/SIZE
{I I -COST OPTIMIZATION
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DEVIL ~t,NY_QN ALIERNATlYEs_
SCHEf~E _ _1181 N SP I LLNAL
LOCATION TYPE
AUX. SPILLWAY EMERG I .s~ I LUiAY
LOCATION TYPE LOCATION TYPE
1 R
2 L
3 R
LEGEND:
L: LEFT BANK
R: RIGHT BANK
D: IN DAr·~l
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D' 0 L
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SB~ STILLING BASIN
UC: UNLINED CHANNElJFUSE PLUG
POWERPLANT; ALL SCHEMES: RIGHT BANK~ 400 MW, 4 UNITS) UNDERGROUND
DIVERSION) ALL SCHEMES: LEFT BANK 2 -26' DIA. TUNNELS.
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DEVIL CANYON
COMPA~~TIVE ESTIMATE SUMMARY -COSTS
( $000 JANUARY 1982) SCHEME 1 SCUE~1E 2 SCHEr1E 3
COf1PA RED ITEMS
DIVERSION 32,100 32,100 35,000
SERVICE SP I lll1AY 46,800 53,300 85,200
SADDLE DAf1 20,000 18,600 20,000
EMERGENCY SPILLWAY 251200 _252QD_ _ _2~2_00
(COMMON IN ALL SCHEMES)
TOTAL C0~1PARED ITEMS 12l!, 100 129J200 165,1100
TOTAL ITEr1S CONSIDERED 7571 9JlQ 757190_Q 757,9_QQ
II COr·1r10N TO ALL SCHEMES u 923,300 SUBTOTAL 882,000 887Jl00
16% CAMP & SUPPORT lf99, 200 502,100 522,600
2u% CONTINGENCY
12.5% OWNER COST, ENGINEERING
-------
PROJECT TOTAL 1,381,200 1,389,200 1,445,900
NOTE: UPPER LIMIT ESTIMATE IN
JANUARY 1982 DOLLARS -
$1,595.~000,000*
* INCLUDED EXTENSION OF TAILRACE
,, TO PORTAGE CREEK AND AUXILIARY POWERHOUSE
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STRUCTURE
DAM
POWER ~ACILITIES
SPILLWAYS
DEVIL CANYON LAYOUT EVALUATIONS
J1ElEBf11 NAT I ON
-THIN ARCH DESIGN
-ELIMINATE ORIFICE SPILLWAY
-LOCATE GOOD ROCK
-OPTIMIZE ORIENTATION
-OPTI~1IZE SIZE
· EVALUATE TAILRACE EXTENSION
-RIGUT BANK MAIN SPILLHAY
-SEPARATE EMERG. FAC.
-EVALUATE CHUTE/FLIP
-EVALUATE STILLING BASIN
QBJECTIVE
-TECH. FEASIBILITY/COST
-TECH. FEASIBILITY
-TECH. FEASIBILITY
-REDUCE COST
-TECH.FEASIBILITY
-COST/SCOUR/ENVIRONMENTAL
TRADE-OFFS
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ALASKA POWER AUTHORITY
SUSITNA HYDROELECTRIC PROJECT
External Review Board Meeting No. #3
MINUTES OF MEETING HELD ON
October 6 -8, 1981, BUFFALO, NEW YORK
APPENDIX B Report of External Review Board
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SUSITNA HYDROELECTRIC PROJECT
EXTERNAL REVIEW PANEL
REPORT NO. 3
DRAFT
October 8, 1981
INTRODUCTION
The third meeting of the External Review Panel for the Susitna Hydro-
electric Project was convened on October 6-8, 1981 at the Acres American
office in Buffalo. In addition to Panel Members, representatives of the
Alaska Power Authority and Acres American were present. Various members
of the Acres American staff presented discussions regarding progress in
geotechnical ar .. eas, seismicity, hydraulics, hydrology, and design. The
discussions were well prepared and presented in such a manner as to give
a maximum amount of information in a reasonable time.
Prior to the meeting Pane1 ~~embers received a document entitled 11 Susitna
Hydro~lectric Project, External Review Board, Meeting #3, Information
Package, October 6-8, 1981". During the meeting other printed information
was
The
and
presented to the Panel as required .
Panel appreciates the efforts of the Acres American Staff in planning
preparing for this very informative and successful meeting.
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SEISMICITY AND SEISMIC GEOLOGY
Excellent progress has been made during the summer months in resolving
most of the uncertainties regarding the possible presence of active
faults in the vicinity of the dam sites, in developing an adequate model
of the seismic geology of the region, and in assessing the maximum levels
of earthquake shaking which could result from events occurring along
the major seismic sources. These studies have led to the following
preliminary conclusions:
WATANA DAM SITE
Four major lineaments were originally identified as being possible faults
in the vicinity of the dam:
(1) The Talkeetna Thrust Fault
(2) The Fins Feature
(3) The Susitna Feature
(4) The Watana River Feature
Field geologic studies during the past several months have developed
evidence indicating that:
(1) The Tal~eetna Thrust Fault is not an active fault.
(2)
( 3)
and ( 4)
The Watana River Feature is not a fault.
The Susitna Feature is not a fault.
The Fins Feature may well be a fault but it is relatively
2
short in length and, since there are apparently no other active
faults in the area, it is very unlikely that it could be active.
In any case its length would preclude the possibility of it
being the source of a significant earthquake.
In consequence, there are apparently no active faults crossing the site
and the major sources of earthquake shaking at the site may be attributed
to earthquakes occurring on the Benioff Zone underlying the site at depth,
the Denali fault, the Castle Mountain Fault, and smallar local earthquakes
occurring with no apparent surface expression in the crust of the Talkeetna
terrain. Considerations of fault distances and possible earthquake mag-
nitudes leads to the coQclusion that the approximate maximum levels of
shaking will be due to the following sources:
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Source Closest Distance Magnitude (Ms) Peak Ace.
Benioff Zone ::: 63 km ::: 8~ ::: 0.35g
Benioff Zone ::: 48 km ::: 7~ ::: 0.32g
Denali Fault ::: 70 km ::: 8+ ::: 0.22g
Local Event * * *
Seismic geology considerations have led Woodward-Clyde consultants to
suggest that the maximum local earthquak~ which needs to be considered
3
(Mean)
is a Magnitude 5~ to 6 event occurring at a distance of about 10 km from
the site. Such an event would produce a peak acceleration (mean value)
of about 0.35g and would therefore not be a controlling event. However,
the Panel believes that in view of the past seismic history and other con-
siderations it would probably be prudent to consider the possibility of
a somewhat larger event at a slightly shorter distance. In which case
the local earthquake would be responsible for the maximum accelerations
likely to develop at the dam site. This does not mean however, that it
will necessarily control the design.
For the Benioff Zone event, which seems to be controlling at this stage,
the motions recommended by Woodward-Clyde Consultants for preliminary
design evaluations appear to be entirely appropri~te.
DEVIL CANYON SITE
At the end of 1980, nine lineaments were identified in the vicinity of
the Devil Canyon site which could possibly be active faults. Field
geologic studies during the past 6 months have led to the conclusion
that only 3 of these features are faults, that the three features recog-
nized as faults are inactive, and that in any case they are so short in
f length that they could not generate earthquakes which would be controlling
events with regard to earthquake motions at the darn site. Thus since there
are no active faults in the vicinity of the dam site, the design earthquake
motions will be determined by similar considerations to those applicable
for the Watana site. The Panel agrees with those conclusions.
* Information to be provided in Final WCC Report
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Consideration of the most significant seismic sources of ground shaking
leads to the following:
Source Closest Distance -Magnitude (Ms) Peak Act. (Mean)
Benioff Zone = 90 km = ~ = 0.3g
Benioff Zone = 58 km = 7~ = 0.3g
Denali Fault = 64 km = 8+ = 0.24g
Local Event * * *
As for the Watana site, there is a need to establish very soon the signi-
ficant characteristics of the local earthquake (in the crust of the
Talkeetna Terrain) in order to finalize the seismic criteria to be used
for project design.
In the light of the information presented at this meeting and on the basis
of past experience, the Panel believes that through the use of appropriate
design and construction procedures, dams with ample margins of seismic
safety can be constructed at both sites. The Panel believes, however,
that the question of seismic effects due to local crusted earthquakes
should be resolved in the next few weeks so that more definitive design
studies can be completed.
ROCK ENGINEERING CONSIDERATIONS
As a result of discussions during this meeting as well as observations
made in the field by Panel member Merritt during the period of 23-25
September, we have the following comments regarding present designs.
WATANA
Every effort should be made to reduce the height of the cut slope at the
inlet to the diversion tunnel. The structures can probably be moved
closer to the river and perhaps shifted slightly in a downstream direction.
The surface excavation at the outlets of the tailrace tunnels and spillway
structures is likewise very extensive. Further detailed examination is
warranted to minimize possible slope stability problems.
* To be provided i~ final WCC Report
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Recent borings in the proposed underground powerhouse site encountered a
zone of soft hydrothermally altered diorite. This is not acceptable
material to have in a major underground excavation. Some shifting of these
openings is required. Considering all borings made in the right abutment,
the general quality of the diorite is quite high and we foresee that
acceptable rock can be found for the proposed structures.
DEVIL CANYON
The graywacke and argillite at this site appear to be of acceptable quality
for the proposed underground structures. No major shear zones have been
recognized in these areas. The underground openings have been oriented
with respect to the major known joint systems and bedding planes. The
present layout is acceptable and it is recognized that some slight shift
could result based upon the results of future exploration.
The axis of the proposed surface spillway on the right abutment will nea~ly
parallel the strike of the bedding of the rock. The required cuts wi~l
daylight the bedding which dips at about 50 degrees into the excavation.
Potential major rock stability problems could result which might not be
solved by simple rock bolting measures. This design likewise requires
your review.
BURIED CHANNEL
The results of all geophysical surveys completed to date have defined a
major channel beneath the plateau on the right abutment at the Watana Site.
The channel is approximately 15,000 ft wide when measured with respect to
that portion of the bedrock channel below the proposed reservoir pool level.
The deepest portion of the channel lies about 450ft below pool level;
however, perhaps as much as 60-70·% of the channel 1 i es 100 ft or 1 ess
below maximum pool level.
The borings completed during the Corps of Engineers study indicated that
the channel is filled with glacial till, outwash, and perhaps lacustrine
deposits. The boring. logs show that boulders (some as large as 12ft) can
be expected in these heterogeneous deposits, either as individual units
or as thick layers. Contour maps made of the bedrock surface suggest a
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wide entrance channel or channnels upstream of the damsite and a relatively
narrow exit into Tsusena Creek downstream of the damsite.
The buried channel on the north slope of the reservoir at Watana Dam is
much greater in extent than was anticipated a year ago and represents one
of the greatest uncertainties associated with the Watana Dam project.
Major problems posed by the presence and extent of this channel are
(1) The magnitude of possible seepage losses through the channel.
(2) The possibility of piping within the channel resulting from
seepage from the reservoir towards Tsusena Creek.
(3) The possibility of seismic instability in the soils comprising
the buried channel under strong earthquake shaking.
It appears that problems (1) and (2) above could be eliminated by construc-
tion of a cut-off wall and grout curtain through the soils filling the channel.
However, the provision of such a cut-off would not solve any problems of
seismic instability on the upstream side of the wall.
Since very little information is available concerning the nature of the
soils forming the channel fill it is not possible to assess the magnitude
of the seismic instability problem, if indeed it exists at all, or the
need for an extensive cut-off wall, currently projected to be about 15,000
feet long and varying from a few feet to 450 feet in depth. However, it
is clear that both the possibility of seismic instability and the cost
of a cut-off would be dramatically reduced if the reservoir level were
about 100 feet lower than currently planned. Such a 'lowering could reduce
the length of the cut-off to about 4,000 feet, facilitate its construction
and by lowering the water table in the soils, increase their seismic sta-
bility. In view of the~e advantages, together with the fact that economic
advantages associated with the top 50 to 80 feet of Watana Dam do not
appear to be very great, the Panel believes that careful consideration
should be given to the potential benefits of reducing the height of Watana
Dam by 50 to 100 feet. Such a reduced height might also facilitate layout
problems for the dam.
The Panel cannot be sure that a reduction in dam height would be advanta-
geous but believes that a careful study of the question is warranted in
the next several months.
I
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WATANA DAM EMBANKMENT
The Panel believes that the preliminary design section selected for Watana
Dam is satisfactory and wili produce a stable and economical structure.
It is suggested however, that consideration be given to the following items:
(1) If the shells are constr~cted of densely compacted gravel
and/or
(2)
(3)
(4)
or rockfill and the core of a much more compressible sandy-
silky-clay, there is a danger of deleterious stress redistribu-
tion due to differential settlements. Thus consideration should
be given to minimizing this possibility py:
(a) inclining the core slightly upstream, providing
this can be done without jeopardizing stability.
(b) locating a relatively incom~ressible core material
which is adequately impervious. Such a material appears
to be available as a GC material in one of the borrow
areas.
Deformations of the upstream shell of the dam due to strong
earthquake shaking can be minimized either by densifying the
shell material to such extent that high pore pressures cannot
develop or by using highly pervious rock-fill which will
dissipate any pore pressures resulting from ea;thquake shaking
almost as rapidly as they develop. Consideration should be given
to using gravel-fill and rock-fill in the upstream shell in such
a way as to optimize their use from a seismic design point of view.
There is apparently ice in the rock joints in the abutments at
Watana dam site and this will have to be thawed before grouting.
It would be desirable to determine whether construction costs
have allowed for this~
It appears that there may well be permafrost in the ~undation
soils for the saddle-dam. When this melts it could ~ave the
soils in a V€ry loose condition which may be adequate for static
stability but inadequate for seismic stability. It would be
desirable to explore this possibility further and examine the
need for exacavation of frozen foundations soils prior to saddle-
dam or dike construction.
DEVIL CANYON DAM
Sufficient study has been completed to adequately support the present arch
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dam design for· feasibility purposes. However, the linear feature through
the pond areas where the wing dam will be located should be further explored
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in the near future. Similar considerations to those discussed for the
Watana Site should be given to the foundation soils under the Devil Canyon
wing dam.
WATANA DAM DIVERSION TUNNELS
Two diversion tunnels are proposed for diverting up to a 1 in 50-year
flood during construction of Watana Dam. One tunnel would be located at a
low level so that it would flow full at all times. The second tunnel,
located at a higher level, would have free flow. After diversion the lower
tunnel would be plugged. Two plugs would be constructed in the upper
tunnel with gated outlets through them to permit release of low flows until
Devil Canyon is completed and serve to lower the reservoir in case of an
emergency. The Panel concurs in the general concept of the diversion
tunnels and modification of the high level tunnel for use as a low-flow
and emergency release outlet, subject to refinements discussed by Ac~es.
WATANA DAM SPILLWAY
Spillway flows at Watana Dam would be handled by three separate flow release
structures. Discharges corresponding up to a 1 in 100-year flood, would
be released through a low-level tunnel controlled by three or more Hewell-
Bunger or similar valves located at the downstream end of the tunnel.
Discharges corr·esponding to floods in excess of 1 in 1 DO-years and up to 1
in 10,000-years would flow through an open chute spillway with a flip
bucket. Discharges in excess of the 1 in 10,000-year flood up to the PMF
would pass through a bypass channel controlled by a fuse plug.
The Panel conc~rs in the proposed concept of handling spillway flows.
Release of fioods up to 1 in 100-years by low level valves would maintain
the nitrogen supersaturation level to an acceptable limit. The Panel
suggests that fixed cone valves, as installed by the Corps of Engineers at
New Melones Dam be used, since its greater rigidity makes it more suitable
for high-head operation. The smaller spillway/chute flows reduce erosion
in the downstream ~·iver channel. Hydraulic model tests will be required
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to determine the extent of material that should be pre-excavated in the
plunge pool area. In view of the infrequency and short duration of spillway
ope~ation and the relatively high quality of rock in the steep river banks,
the Panel is of the opinion that excessive erosion would not occur due to
' service spillway operation. With respect to the emergency spillway bypass
channel, the Panel is concerned over the 45-ft height of the fuse plug.
This high plug would need to be designed as a small earth dam to retain the
power pool at maximum levels and also be capable of failure as a fuse plug
when it is overtopped. It is suggested that the entrance to the bypass
channel be widened, thereby requiring a smaller height of fuse plug. This
would also reduce the amount of reservoir lowering in the event of fuse plug
failure.
DEVIL CANYON DIVERSION TUNNEL
One diversion tunnel is ~r0posed for Devil Canyon Dam to divert flows up to
a l in 50-year flood during dam construction. The tunnel would be plugged
after it is no longer needed for diversion. The Panel suggests that this
tunnel could be used for spillway flow releases in an alternative spillway
design discussed hereinaftere
DEVIL CANYON SPILLWAYS
As for Watana Dam, spillway flows at Devil Canyon would be handled by three
separate flow release structures. Flows up to the l in 100-year flood
would be released by four or five outlets through the base of the concrete
arch dam controlled by Howell-Bunger or other type high pressure valves.
Discharges in excess of 1 in 1 00-years and up to 1 in 1 0,000-years would
fiow through an open chute spillway with a high level flip bucket. Dis-
charges in excess of the 1 in 10,000-year flood up to the PMF would pass
through a bypass channel controlled by a fuse plug.
The Panel concurs in the concept of handling the spillway flows subject to
one question discussed below. Release of small flows through valves at
the base of the dam will prevent excessive nitrogen supersaturation in
the downstream river channel, as well as reduce discharges and flow fre-
quency and duration in the chute/flip bucket spillway, thereby reducing
plunge pool erosion. Based on a ground and air inspection of the river
channel at the Devil Canyon Site by Panel member Douma and Acres repre-
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sentatives on September 17, 1981, the Panel is of the opinion that the very
high quality rock in the canyon walls should not experience excessive
erosion due to spillway operation. In this case, pre-excavation of streamed
material and weathered rock is probably not required. The Panel is con-
cerned, however, over the deep sidehill rock cut required for construction
of the spillway chute. It suggests that consideration be given to an alternate
plan of providing spillway tunnels, as required, instead of the chute spillway.
In this alternate plan, the diversion tunnel and probably only one addi-
tional tunnel would be required. With respect to the emergency bypass channel
spillway, the Panel is concerned over the 57-foot high fuse plug for the ,
reasons stated for the Watana fuse plug. Consideration should be given to
increasing the length and reducing the height of this fuse plug as described
for Watana.
DEVIL CANYON POWERHOUSE TAILRACE
The Panel concurs in extending the tailrace for the Devil Canyon powerhouse
about 1 1/4 mile to take advantage of the additional approximately 30 feet
of head.
CLOSING REMARKS
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The Panel requests that the topics raised in this report be thoroughly
discussed in the next External Review Board Meeting tentatively scheduled
for the week of January 11, 1982 in Anchorage.
The Panel greatly appreciates the many courtesies extended to it by the
staff of the Alaska Power Authority and the staff of Acres American, Inc.
Merlin 0. Copen Andrew H. Merritt
Jacob H. Douma H. Bolton Seed
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