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'(\0 -3o<loq "November 1981
InterviEtwS wi'th eminent scientists,engineers and economist give
insight into proposed Susitna hydroelectric project
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•decision criteria for Choclsing hydro
and
future markets for electricity see p.9
•earthquake·safedam design
and construction see p.2
•comparison between Sus,itna and
Rampart d~lm proposal 011 the 60's
and
potential impacts on fish and
wildlife see p.13
•foundation conditions and IQw
temperatures see p.22
•-spillways,stilling basins,nitrogen
supersaturi!ltion and fish ...see p.26
•underground tunnels and
powerplartf:s see p.18
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Earthquakes in this region 968
constitute lhe Benioff Zone
Alaska Power Authority
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Susitna External
Review Panel
INTRODUCTION
In 1979 the Alaska Power Authority
Board of Directors created a separate
fund to provide for an independent
review of the Susitna hydroelectric pro-
ject feasibil ity study.
The purpose of the fund is twofold:1)
to provide a second,independent cost
estimate of the project;and 2)to hire
experts in those areas of concern that
are crucial in determining the project's
feasibility.To ensure an objective
assessment of the proposed Susitna
project,an external review panel of
eminent scientists,engineers,and
economist was selected to review the
project.
THEIR ROLE
This group of experts,the Susitna Ex-
ternal Review Panel,was selected by
the Board of Directors mid-way through
the first year of the feasibility study.
Although the Power Authority staff pro·
.vides administrative support to the
Panel,the Panel reports and is respon-
sible directly to the Board of Directors.
Panel members are encouraged and
given the freedom to raise sensitive
issues and can conduct separate,in·
dependent studies as necessary.
THEIR WORK
The Panel has met as a group three
times.Two additional meetings are
scheduled.During the first year and a
half of the feasibility study,the Panel
has focused on the following issues:
•the seismic conditions of the upper
Susitna Basin
•potential impacts on fish and
wildlife both in the reservoir areas
and downstream
•the level of energy conservation in-
corporated into demand forecasts
•the comparative cost and risk of the
Susitna project in relation to other
power generating alternatives
•the design and construction of
earthquake-safe dams
•the capability and design of
spillways to handle high river flows
•foundation conditions and con-
struction materials at the proposed
sites.
THE RESULTS
The External Review Panel is schedul-
ed to formally report to the Power
Authority Board of Directors during the
week of April 12,1982.The Panel will
report on the adequacy of the draft
feasibility report and present its own
recommendations in advance of the
Power Authority's report on the pro-
ject's feasibility to the Governor and
the Legislature.
ARLIS
Alaska Resources
Library &Information Services
AnchoFWc A1Clsk::t
ARLIS
/I.laska Resources Library &Information Services
Library Building.Suite 111
3211 Providence Drive
Anchorage,AK 99508-1614
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.Alaska Resources
Library &In.&:..'..lorm.iDon ServicesAnchorag~J Alaska *The interviews were conducted in February 1981 by Nancy Blunck,Director of
Publ ic Participation,the Alaska Power Authority.They are reproduced by special
request.
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1 Earthquake-resistant
design
Dr.H.Bolton Seed is a forml~r chairman
of the Department of Civil Engineering
at the Berkeley campus of the Universi·
ty of California.A specialist in earth-
quake engineering problems,he has
consulted on over 80 dams worldwide,
most of which are in seismic areas.
...page 2
4 Geo.tech~ical
engmeermg
Dr.Andrew H.Merritt is i3.geologist
who has been "involved in the research,
design,and review of major construc-
tion projects around the world.A
specialist in tunnels and rock work,he
has extensive experience with hydro-
electric and nuclear power projects.
...page 18
2 Economic analysis
Dr.Dennis M.Rohan is an economist
with the Stanford Research Institute
who specializes in energy matters.He
has been involved in economic an·
alyses of all phases of energy produc-
tion and consumption.
...page 9
5 Concrete structures
Merlin D.Copen is an expert on con-
crete dams.He has had major respon-
sibility for the design of the Glenn Can·
yon Dam on the Colorado River,Califor-
nia's Auburn Dam (proposed as one of
the longest concrete arch dams in the
world),and many others.He has con-
sulted on numerous international pro-
jects as well as other Alaskan
developments.
...page22
3 Environmental studies
Dr.A.Starker Leopold is a distin·
guished zoologist who has been
associated with the University of
California since 1946.A one-time vice-
president of the Sierra Club,he has
served on many wildlife and conserva-
tion organizations and has conducted
extensive research around the world .
...page 13
S ·Hydraulics and river
flow
Jacob H.Douma served as chief of the
Hydraulic Design Branch of the U.S.
Army Corps of Engineers prior to his
retirement from active government
service after more than 40 years.In ad-
dition to his government work on
American dams,he has extensive con·
sulting experience with Canadian
hydroelectric projects.
...page 26
earthquakes/page 2
Intervievv I
Dr.H.Baton Seed
1,1
Dr.H.Bolton (Harry)Seed is a specialist in
earthquake-resistant design and professor of
civil engineering at the University of Califor-
nia,Berkeley.
Dr.Seed has been a consultant on soil me-
chanics and seismic design problems since
1953.Over the years,he has worked exten-
sively with a variety of clients,including the
U.S.Army Corps of Engineers,the Executive
Office of the President of the United States,
the World Bank,the Federal Power Commis-
sion,Bechtel Corporation,Woodward·Clyde,
the Metropolitan Water District of Los
Angeles,the Canadian Ministry of the En-
vironment,and many foreign government
agencies.
Dr.Seed has worked on about 80 dams
worldwide,most of which are in seismic
areas.After a dam failure in California in the
early 70's,Dr.Seed authored design pro-
.cedures for Cal ifornia so that dam failures
would not happen again.These procedures
are now used throughout the world to pro-
duce safe,seismic designs for dams.
Question:What past experiences do you have in Alaska?
Seed:After the Alaska earthquake,the Corps of Engineers
was assigned responsibility for studying all the landslides in
Alaska,the safety of the areas,the safety of the towns of
Valdez and Seward where there were landslides,and other
areas.They didn't have the staff to do it,so they contracted
much of the work to a company called Shannon and Wilson
from Seattle.I served as a consultant to Shannon and
Wilson and,therefore,indirectly to the Corps of Engineers
on the landslide areas in Alaska.
In deciding on the work and who would do what,I was
given primary responsibility for determining the cause of the
Turnagain Heights landslide.I must have travelled from here
to Alaska about 10 or 12 times in the six months after the
earthquake.Each trip was three to six days.I spent a lot of
time at Turnagain on drill rigs,studying soil samples as they
came out of the ground.I carried samples of Bootlegger
Cove clay back on the airplane on the seat next to me so that
it wouldn't be unduly disturbed by transportation.We did a
lot of testing in our laboratories at Berkeley on the Boot-
legger Cove clay as well as other studies.We eventually
analyzed the problem and made a report to the government.
We also reported our findings in the professional literature,
and it seems to be a well-accepted version of the cause of
failure at Turnagain Heights.I also studied the Fourth
The design of the Oroville dam in California has been suggested as an ap·
propriate model for the preliminary earthquake design of the Watana dam.It is an
earthfill dam like Watana is proposed to be,is in a seismic area,and is of a similar
height (Oroville is 770 feet,Watana is proposed to be 880 feet).
The design earthquake for Oroville was a magnitude 6.5 earthquake occurring
directly under the dam site.The Oroville dam design accommodates strong mo·
tions very near the dam for a relatively large earthquake.
.-
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Avenue slide,the L Street slide,the
First Avenue slide,the Valdez harbor
slide,and the Seward harbor slide.In
addition to that I have served as a con-
sultant to various companies dealing
with the design of the Alas~,a pipeline.I
served as a consultant to a structural
engineering company who made a
study of the safety of the Anchorage
port facilities following the 1964
Alaska earthquake,and I conducted a
detailed study of the influence of foun-
dation conditions on the damage to
bridges,both highway and railroad
bridges,in the 1964 earthquake.
Question:What is your personal ex-
perience with design of darns?
Seed:Since I am a specialist in
earthquakes,I tend to gist involved
more with dams in highly seismic
regions than other areas.So,for exam-
ple,I've worked on a lot more dams in
California than with dams in Texas and
Florida,which are nonseismic regions.
My experience includes design of,
perhaps,80 dams-50 or 80 dams for
earthquake problems of one kind or
another.I suspect that I have worked
on more earthquake problems related
to dams than anybody else in the
world.
Question:What other projects are
you familiar with that resemble the
Susitna project?
Seed:The Oroville dam in California
is a cobble and gravel fill dam 700 feet
hi!gh.The Auburn dam in California is a
concrete dam about 600 feet high.
Revelstoke dam in Canada has both a
concrete section and an earthfill sec-
tion on the Columbia River.The
Uribante-Caparo project in Venezuela
is a complex of four dams and three
powerhouses,with 400 to 500 foot high
dams.The Alicura project in Argentina
is a complex of three dams about 400
feet high.The Boruca project in Costa
Rica is expected to be a rockfill dam
600 feet high.Dartmouth dam in
Australia is a rockflll dam 600 feet high.
The Pueblo-Viejo dam in GUiatamala is
a rockfill dam 500 feet hi~lh.Tarbela
dam in Pakistan is a cobble and gravel
fill dam about 450 feet high.And many
others.
I served as a consultant on the earth-
quake resistant design of 'all these
dams.
auestion:How do these projects
resemble Susitna,and are there greater
or lesser problems?
Seed:The Oroville dam is in Califor-
nia.The region in which it was built
wa.s supposedly nonseismic,but in
1965 they had an earthquakE~very near
the dam.So the design eartlhquake for
Oroville is now a magnitude 6.5 (on the
Richter scale)earthquake occurring
directly under the dam site,which is a
very strong earthquake.
Oroville is about the same height as
the proposed Watana dam and,as a
matter of fact,was the one we sug·
gested in our first report as probably
being the best model for that particular
dam.I have been on the consulting
board for that dam since it became an
earthquake problem,which means
having responsibility for determining
the adequacy of the seismic design.
There is a report on the subject
which is available to the public and
widely disseminated.I also talked
about that dam in a special lecture I
gave in London called the Rankine lec-
ture which was presented to the In-
stitute of Civil Engineers on the
seismic stablility of dams in general,
including Oroville as an excellent ex-
ample of how dams might be in-
vestigated.
The Auburn dam in California is a
highly controversial dam.Again,the
design earthquake is a magnitude 6.5
event directly at the dam site.The com-
plicating feature of that dam is that
there is much debate about the
possibility of a fault going through the
foundation of the dam and,therefore,
directly through the dam.
The Consulting Board on which I
served determined that the darn ought
earthquakes/page 3
to be designed for a fault offset in the
foundation of about 6 inches.That
recommendation led to redesign of the
dam from the thin arch dam to a con·
crete gravity dam.It was a highly con-
troversial decision.In fact,the federal
government doesn't normally take ad-
vice from the states on how they
should do their job.But nevertheless,
the State of California did get the
Secretary of the Interior to agree to
abide by whatever criteria the Con·
suiting Board on which I served would
establish for that dam.As a resultof
those criteria the federal agency
designing the dam decided to change
the kind of dam they were going to
build.
The Uribante-Caparo project in
Venezuela involves four dams and
three powerhouses and some parts of
this project are built about 15 miles
from the Bocono fault,which is one of
the largest faults in the world.
The seismic design of the project is
an important controlling aspect of the
project.The materials available for
building the dams are not the best in
the world.There is a lot of friable sand-
stone (friable means breaks easily,
from solid to sand),and so it turns out
that designing the dam to be seismical-
ly stable is a critical aspect of the
design,and we have been working on
earthquakes/page 4
that problem for the past two or three
years.One of the design earthquakes is
a magnitude 7.5 event occurring about
seven miles from the dam.This is
almost identical with one of the possi-
ble design earthquakes for the Watana
dam unless Acres is successful in
proving that the Talkeetna thrust is not
active.At the present time,the Talkeet-
na thrust is a fault near the Watana
damsite whose activity is questionable
but it is believed to be inactive.If it re-
mains in the inactive category,then the
severity of shaking for Watana will be
less than that for Uribante-Caparo pro-
ject in general.
The Alicura dam is the highest and
one of the first dams in Argentina to be
designed for earthquakes using
modern approaches.
The fault that affects the dam most
is off the coast of Chile.One of the
main problems is that we are trying to
predict the kind of ground motions that
will result from an earthquake with
magnitude 8.5 at a distance of about
120 kilometers (72 miles)when there
has never been a record of such an
earthquake ever made.
The dam also happens to respond
very strongly to that kind of motion and
so the earthquake-resistant features of
the design become a critical matter.
Another big problem is to determine
whether or not the material in the foun-
dation of the dam needs to be ex-
cavated or can be left in place.This
decision is affected directly by the
design criteria for the dam.
Dartmouth dam in Australia is a
rockfill dam 600 feet high (about the
same height as the dams that are being
proposed in the Susitna project).There
is a suspicion of a fault very near the
dam which could produce a magnitude
7 earthquake.This would be a more
severe condition than we are talking
about presently for Susitna,and the
problem there has been to produce a
design which would safely withstand
that kind of earthquake.We have done
that.
Incidentally,on all these dams,
designs have been produced which
have been adequate to accommodate
the motions produced by the earth-
quakes.It is a matter of how you build
the dam,how you arrange the dam,
what materials you use in the dam,and
how you place the materials in the
dam.These factors will determine
whether the dam will adequately with·
stand the effects of the earthquake.
The Pueblo Viejo project in
Guatemala is designed for a magnitude
7.75 earthquake passing directly
through the project site-not the site
of the dam,but the overall project site.
The fault passes through a power tun-
nel very close to the dam site.The
shaking there is of the order of 0.7g
[0.4g for WatanaJ acceleration,lasting
for maybe 45 seconds-one of the
most severe seismic environments of
any dam in the world.Nevertheless,a
safe design has been worked out for
that project.
Tarbela is another major dam which
has major faults very close by or direct-
ly below the dam site,and the shaking
there is probably as strong as you
would get in many parts of the world.
We are working to make sure that the
dam will be safe against earthquakes.
Revelstoke dam in Canada is an in-
teresting problem.We had very poor
foundation material,and the question
there was whether or not the founda-
tion material should be excavated or
not.In the final analysis it was decided
that the foundation material was not
good enough to support the dam,so
they made an excavation about 200 feet
deep to remove poorer quality material
and replace it with good quality
material on which to build a safe dam.
"...the earthquake·resistant
design of dams has been
totally revolutionized in the
last 10 years."
Question:What knotty problems
have you encountered on other
hydroelectric projects?
Seed:Any problems that you en-
counter are essentially related to three
major ones-the amount of water to be
stored and the amount of flood water
that has to be stored at any given time;
the stability of the enbankment and
foundation materials;and the possible
effects of faults in the foundation.The
first is not my area of expertise.It is a
hydrological problem and there are
other specialists who can handle that
part of the problem.I would say the
most difficult problems in the earth-
quake sense are primarily those of
evaluating the stability of the founda-
tion materials on which dams are to be
built.
For example,there was much debate
about the safety during earthquakes of
Revelstoke Dam in Canada and what
they should do about the foundation.I
was invited to be a consultant on that
project because of the different points
of view about the safety of the dam.
There were public hearings.The
Ministry of the Environment promised
the people that they would ensure that
a safe dam would be built.Having
made that promise,they appointed a
review panel to advise them on how
they should proceed to be able to fulfill
that promise to the people.
They were dealing with a very dif-
ficult foundation soil.As a matter of
fact,I told them that the foundation
soils in some parts of the dam founda-
tion bore a great resemblance to those
at Turnagain Heights in Alaska (the
soils that failed in the 1964
earthquake).Some of the foundation
material for Revelstoke Dam reminded
me a lot of Bootlegger Cove clay.I told
them that it was an unstable material,
especially at the level of shaking they
were designing for.I advised them to
excavate the material out,and that's
what they elected to do.I would say
that was a knotty problem.
Other knotty problems involve faults
in the foundation.After the San Fer-
nando Dam nearly failed in the San Fer-
nando earthquake in California,the
people living downstream did not want
another dam to be built at that site,but
it turns out to be a critical point of en-
trance for water into California for the
city of Los Angeles. Therefore,the
Department of Water and Power in Los
Angeles considered it essential to have
a reservoir in that area,and it was
necessary to rebuild the dam at that
location.There was a possibility of a
fault movement in the foundation,so
we had to devise a special design
which could accommodate a very high
level of shaking and the possibility of a
fault movement in the foundation both
occurring at the same time.That was
successfully done.
The Teton dam involved problems
with highly erodible soils.The dam
failed,but I believe that if the design
had been modified,a safe dam could
have been built at that site.The knotty
problem there was assessing the effect
of the jointing of the rock and the
simultaneous erodibility of the soils
used to build the dam on the safety of
the dam.That was a tricky problem.
The engineers who made the design
thought they had solved it,but as
events eventually proved,they had not.
The dam failed.I believe we know
enough about it now that we could
rebuild the dam very safely.
There are knotty problems with many
dams to tell you the truth.Under the
Alicura dam project is a layer of 50 feet
of alluvium.We have spent two years
debating whether that material should
be taken out or left in place.It is a
critical decision because removing it
involves lots of money.If it proves un-
necessary it would be a waste of
money,but to leave it in and make the
structure unsafe could be catastroph-
ic.A lot of thought has gone into the
question of whether it can be left in
place safely or should be taken out in
the interest of pUblic safety.I think we
have just about reached a decision that
it can be left there safely.
To tell you the truth,I don't know of
any dam which doesn't involve one or
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two knotty problems.
Question:What are the major causes
of dam failure?
Seed:It is well known that there are
only a few basic causes of dam failure.
The primary cause is overtopping-
someone has not estimated the flood
correctly,and you get more water to
store than the dam can hold.Second,
we have the possibility 01 slides in
earth dams.Third,seepage problems
can cause instability of the dam.I
suspect that those three cause 80 per-
cent of all dam failures.
The last big dam that hacl problems
with seepage causing instability was
the Teton dam.I believe that was the
largest earth dam in which a failure has
ever occurred.The failure occurred in
1976 in Idaho.Because it was built by a
federal agency and because it was
such a big dam (about 350 to 400 feet
high)and it failed totally,all the water
in the reservoir was let out causing a
lot of flooding downstream.The
Secretary of the Interior and the gover-
nor of Idaho appointed a spl~cial board
to investigate the cause of the failure.I
was a member of that '10-member
board,and we did conduct the study
and came up with a conclusion as to
what caused the dam to fail...
Question:What can we learn from
past failures?
Seed:We can learn a great deal.The
dam from which we learned most about
how to build dams for earthquake safe-
..Editor's note:The conclusions are available in "Report
to U.S.Department of the Interior and State of Idaho on
Failure of Teton Dam,"by Independent Panel to Review
Cause of Teton Dam Failure,December 19i6.1t is available
through the Alaska Resources Library at the Federal
Building in Anchorage.The panel concluded:
"In briefest summary,the Panel concludes (1)that the
dam failed by internal erosion (piping)0'1 the core of the
dam deep in the right foundation key trench,with the
eroded soil particles finding exits through channels in
and along the interiace of the dam with the highly per·
vious abutment roc]<and talus,to points at the right
groin of the dam,(2)that the exit avenues were
destroyed and removed by the out rush of reservoir
water,(3)that openings existed throullh inadequately
sealed rock joints,and may have developed through
cracks in the core zone in the key trench,(4)that,once
started,piping progressed rapidly through the main
body of the dam and quickly led to complete failure,(5)
that the design of the dam did not adequately take into
account the foundation conditions and the character-
istics of the soil used for filling the key trench,and (6)
that cOnstruction activities conformed to the actual
design in all significant :sp.ect~except scheduling."
"The difficult conditions of the site called for basing the
design on the most unfavorable assumptions compatible
with the geologic conditions concerning the behavior of
the water and Its possible effect on the embankment.In·
stead of placing so much dependence on Ilhe key trenches
and grout curtain,measures shouid have been developed
to render harmless whatever water did pass,.irrespective
of the reasons.
"In final summary,under difficult conditions that called
for the best judgment and experience of the engineering
profession,an unfortunate choice of design measures
together with less than conventional precautions was
taken to ensure the adequate functioning of the Teton
Dam,and these circumstances ultimately led to its
failure."
ty was probably the Lower San Fernan-
do Dam in California,which had a big
slide in it during an earthquake in 1971.
As a result of that slide,80,000 people
were evacuated from their homes while
the reservoir was emptied or drawn
down to a safe level.That could have
been a big disaster,but it was not.
I happened to be the person ap-
pointed to study the cause of that
failure and report on it to the
Legislature of the State of California
and prescribe and recommend design
procedures for California so that a
similar event could never occur again.
Those procedures are the ones now be-
ing used in California and largely
throughout the world to produce safe
designs for dams.
We have applied these procedures to
maybe 16 dams whose performance
during earthquakes is known--either
the dams have suffered slides or they
have not suffered slides.It works out to
have given the right answer to every
case that we checked it against.So
this is now what is called a validated
procedure,and there is a growing
degree of confidence that we now
know how to use the procedure as a
guide in arriving at the correct design
decisions.
Question:Can you summarize those
procedures?
Seed:It is quite a long procedure,
and it is hard to summarize in a few
words.It involves first determining the
kind of earthquakes that will affect the
dam and,secondly,how the dam will
react and respond to the ground shak-
ing to which the dam is subjected.
Third,by means of laboratory telsts on
samples of the soil which will eventual-
ly be used in the dam,we can deter-
mine whether those soils will be strong
enough to withstand the stresses
which will be imposed on them if they
were built into the dam.The laboratory
tests also determine how the soil must
be placed in the dam in order that it can
withstand the stresses which will be
imposed on it by the earthquake.The
last step is building the dam to have
the level of strength required.
Question:What about the question
of building safe dams in a seismic
area?.
Seed:First of all,it is comforting
that at the present level of knowledge
of the Susitna project the intensity of
shaking which can be anticipated at
either dam site is considerably less
than those in areas for which we have
already designed dams.Secondly,the
people in Alaska,and Talkeetna par-
ticularly,should know that dams have
been proposed to be built in some ex-
tremely critical areas.
The Auburn dam in California has
been a source of great controversy.It is
earthquakes/page 5
planned to be built about 25 miles
north of Sacramento.The controversy
was over the potential hazard it
presented to the people of California.If
the Auburn dam were to fail,it has
been argued,it would cover Sacramen-
to with water to a depth of about 25
feet in a period of one hour and would
kill a million people in the process.
That is a very dangerous place in which
to build a dam.Nevertheless,the pro-
ject was studied by a great many
boards of consultants and it was deter-
mined that a safe dam could be built
there if it was built properly-in other
words,if the right kind of dam were
chosen and properly designed.
Most people now have no fears
about it.Even people living down-
stream of the dam were eventually con-
vinced.In fact,there were some well-
known engineers who would live
downstream of that dam who testified
before the Seismic Safety Commission
of California that if the right kind of
dam were built by the right kind of peo-
ple,they would not be concerned about
living downstream.
"...it is a comforting fact that
at the present level of
knowledge of the Susitna
project,the intensity of
shaking which can be
anticipated at either dam site
is considerably less than
those for some areas for
which we have already
designed dams."
Question:How often have you had to
design to withstand earthquake activi-
ty?
Seed:In principle,all dams are
designed for some level of earthquake
shaking.That is a standard recommen-
dation because until recently it was
thought that building a dam and filling
a reservoir could trigger earthquakes
where there had not been any in recent
history.Actually,there has to be some
degree of seismic activity for that to
happen,but maybe it hasn't happened
in recorded history.Filling a reservoir
can trigger seismic activity which has
been lying kind of dormant for a long
period of time so nobody knew much
about it.Dam-building agencies now
advise that all dams should be de-
signed for a low level of earthquake ac-
tivity no matter where they may be.And
then certain dams which are designed
in highly seismic regions should be
earthquakes/page 6
designed to withstand very high levels
of seismic activity.
Question:What is "reservoir-induced
seismicity?"
Seed:Let me try and put that into
perspective for you.A reservoir cannot
induce more seismic activity than an
area could have produced if the reser-
voir had not been there.All that a reser-
voir can do is to make the earthquake
that would have occurred sooner or
later occur sooner.So reservoirs don't
make areas have greater earthquakes
than they otherwise would have had.
They just make earthquakes which
would have occurred later occur
sooner.So in any of the dams that we
are talking about with Susitna,
reservoir-induced earthquakes are not
going to be greater than earthquakes
which would naturally occur in those
regions in the course of time.
Question:What particularly must
dam design in highly seismic areas
take into account?
Seed:The first thing in a highly
seismic area is to study the dam site
and find out if there is a fault in the
foundation of the dam or very close to
the dam.We prefer not to build dams
directly over faults,although once in a
while we have done that when there is
no way to avoid it.
Even if you avoid the faults in a
highly seismic region,that doesn't
eliminate the problem of the dam being
subjected to extremely strong ground
shaking in the event of a major earth-
quake.Accelerations could approach a
value of about 0.8 of the acceleration of
gravity and persist for some con-
siderable time,as people in Alaska well
know if they were located near the
epicentral region of the 1964 Alaska
earthquake.
So the second aspect of the problem
is to design the dam to remain stable
even though it is shaken by very strong
motions from an earthquake.There are
various ways in which that is effected.
One is by controlling the materials of
which the dam is built.When I say con-
trolling them,I mean selecting
materials which are capable of
withstanding earthquakes better than
others;also,placing them in the dam
using construction techniques which
enhance their natural ability,and pro-
viding a finished product which can
safely withstand the effects of the
earthquake shaking.
The primary construction procedure
involved in placing earth materials in
dams is in compacting the material to a
high enough density to make it strong
enough to withstand the earthquake
shaking.That has been done in many
areas,but first you must carefully
predict the effects of earthquake shak-
ing on the dam and how dense the
material needs to be to withstand a
1"'"'
i-
i'
given level of earthquake motions.
There is a new problem which has
only come to light in the last few years.
That is that the most critical time in the
life of some dams appears to be not
during the earthquake but in periods of
minutes to hours following the earth-
quake.We didn't really fully appreciate
that until a dam in Japan failed in 1978.
The failure occurred somewhere be-
tween six and 24 hours after the earth-
quake.That was the first time that
anybody realized that the critical time
for instability could occur some hours
after an earthquake.Until then,it was
thought that failure would occur during
an earthquake if it was going to occur
at all.We have now developed pro-
cedures for analyzing the failure of the
dam in Japan and shown that the
critical time for that dam would indeed
develop about 24 hours after the earth-
quake occurred.Those procedures are
available for analyzing other dams in
other parts of the world.
Question:What's new in the field of
earthquake engineering?
Seed:There has been tremendous
progress in the field of earthquake
engineering,and the earthquake-
resistant design of dams has been
totally revolutionized in the last 10
years.It is almost like th,s develop-
ments of space technology.Things we
can do now,our understanding of the
problems now,are so very much
greater than they were 10 years ago
that we can feel enormous confidence
now in comparison.In those days peo-
ple felt confident because they didn't
really understand the problems.Now
we feel confident because we have a
very good understanding of the prob-
lems.
Question:Can you give some ex-
amples of why you can be so confi-
dent?
Seed:We can point to viirtually
dozens of dams which have withstood
very strong earthquake shakinl;l,even
the strongest imaginable earthquake
shaking.In California,in 1906 there
were at least 15 dams within 5 miles of
"[Ten years ago]people felt
confident because they
didn't really understand the
problems [of earthquake·
resistant design].Now we
feel confident because we
have a very good
understanding of the!
problems."
the San Andreas fault on which a
magnitude 8.3 earthquake occurred,
and they were built by the rather
primitive pre-1900 construction
methods.There wasn't a single one of
them that suffered any major damage
due to the earthquake.During the last
earthquakes/page 7
10 years we have learned what the pro-
perties of those dams are that enabled
them to do that.We can also point to a
few dams that have failed during earth-
quakes and what we have learned over
the last 10 years is what made those
dams fail as compared with the other
ones that haven't failed.There are a lot
more dams which have been subjected
to strong earthquake shaking and not
failed than those that have been sub-
jected to strong earthquake shaking
and have failed.
The record is very positive.There
have been literally hundreds of dams
which have withstood strong earth-
quake motions.In the total history of
the United States,so far as I know,I
think there are only four or five known
failures of dams during earthquakes,
and some of those were quite small
dams.Now that we better understand
which ones are likely to be vulnerable
and which ones are likely to be safe
and how to transform the unsafe ones
into safe ones,I believe everybody can
sleep more peacefully at night.
In the most recent survey of the safe-
ty of dams in California (conducted by
the federal agency responsible for
studying the safety of dams),the con-
clusion was that there are no dams in
California which are a threat to the
public,and we could not have said that
10 years ago.In the last 10 years there
have been a number of dams in Califor-
nia which have been recognized as
earthquake hazards that have either
been taken out of service or rebuilt or
-
/
0°.Q.Oo~oo
Earthquakes in this region 96
constitute the Benioff Zone
Alaska is part of a large continental landmass (the North American Plate)which lies adja-
cent to an oceanic mass (the Pacific Plate).The Pacific Plate is moving northwest at a rate
of about 2 inches per year.
This 2 inches of movement gets absorbed along a feature in the Gulf of Alaska called the
Aleutian Trench.Here one plate is thrust below the other (in a process called subduction)
as shown in the diagram.The zone of seismicity associated with the subduction is referred
to as the Benioff Zone.
-------------_._----------------_.----------------------
earthquakes/page 8
modified in some way to eliminate the
threat to the public.As I said,the last
report I saw from the federal agency
responsible for assessing the safety of
dams gave California a clean bill of
health.
California is obviously one of the
more seismically active states in the
United States,along with Alaska,and if
we can do it here,you can do it in
Alaska,too.
"...if the Talkeetna thrust
turns out to be an active
fault,then the level of
shaking at Susitna would be
comparable to that of some
of the strongest seismic
regions where dams have
been built...we have been
able to build and design
dams which can be shown to
be seismically stable in
those regions ...[those)
techniques would be capable
of demonstrating the same
for Susitna."
Question:How does the seismicity
of the Susitna area compare to the
seismicity of other projects you have
worked on?
Seed:I would say that the seismicity
of the Susitna area as it is presently
understood(and if it is established)is
somewhat less than that which I have
encountered in other parts of the
world.There are a number of faults
whose activity has not yet been
established in the Susitna area.They
are believed to be inactive faults,but
they are on record for being in-
vestigated very carefully during the
1981 summer.The Talkeetna thrust
fault is one of these and probably the
most important of them.If all the faults
that are presently not clearly recog-
nized as active are found to be inactive,
then the seismicity of the Susitna area
(or the intensity of ground shaking that
would develop)would not be as strong
as many of the dams that we have
already designed.That would be a very
nice feature of the project.In other
words,if things turn out in the long run
(after another year of study)to be the
way they presently appear (and that re-
mains to be confirmed),then there will
be many dams in the world which have
been designed for stronger levels of
earthquake shaking than would be
necessary for the Susitna project.
Question:And what if the opposite
were true?
Seed:If the opposite were true,if the
Talkeetna thrust turns out to be an ac-
tive fault,then the level of shaking at
Susitna would be comparable to that of
MOUNTAINS
some of the strongest seismic regions
where dams have been built.
Since we have been able to build and
design dams which can be shown to be
seismically stable in those regions,
then I believe that the same techniques
would be capable of demonstrating the
same thing for the dams of the Susitna
project.
The design in any case will require
great care but it would require even
more care if those faults like the
Talkeetna thrust turn out to be active
faults.But I don't see that the dams
cannot be designed to withstand these
motions.They just have to be stronger
dams so they can withstand the motion
without in any way jeopardizing public
safety.
»\~r-Z
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\
To date no active faults have been identified in the Talkeetna Terrain itself.Studies in 1981
are further evaluating 13 faults and lineaments (potential faults)in the vicinity of the
Watana and Devil Canyon damsites to determine whether or not the faults and lineaments
may be active.One of those receiving additional study is the Talkeetna Thrust Fault.
economics/page 9
Intervievv 2
Dr,Dennis M,Rohan
Dr.Rohan has training and experience in
both engineering and business.He has con-
sulted with executives in energy and utility
companies on the analysis of the markets,
economics,financing,politics,and technol-
ogy of energy and other resou rce-based i n-
dustries.
At Stanford Research Institute he has
been involved with planning strategies for a
large gas pipeline company,a major chem-
ical company,oil corporations,and six major
electrical and gas utilities.His work also in-
cludes energy fore~casting and economic
evaluation of many projects in the United
States and Canada.Since 1973,he has been
a member of the DHcision Sciences faculty
at Stanford Graduate School of business
where he teaches in the areas of quantitative
methods,computHrs,and energy eco-
nomics.
Question:What Alaska experience do you have?
Dr.Rohan:It has been very limited.As I mentioned,the
one project that I did work on was a market and economic
feasibility study for Beluga coal.
Question:What other projects do you know about that
resemble the Susitna situation?
Dr.Rohan:In terms of similar projects,let me first
describe the scope of my energy consulting work.Most of
this work has been in the areas of market,financing,
economics,and decision analysis-the competitive
economics of one type of energy source versus another.
A first group of projects,more on the market side,was for
British Columbia Hydro,the Alberta Utilities,Manitoba
Hydro,Ontario Hydro,and Hydro Quebec.This work was
sponsored by the Canadian Electrical Association to help
them to better assess their future markets for electricity.
Another study was for the commission in Minnesota on
the need for power.The results were directly related to some
expert testimony on the need for two large coal-fired units.
Still another was for Consumer's Power Company,a very
large utility in Michigan outside of Detroit.Their questions
involved the future markets for electricity and the com-
petitive role of gas.
••
economics/page 10
I also directed a major study for a
group of utilities in the Midwest,in-
cluding Wisconsin Electric,Wisconsin
Power and Light,Wisconsin Gas and
Electric,and several others.The
utilities were trying to better under-
stand their environment and make
some important decisions about the
need for power and the kinds of units
(gas,coal,or nuclear).The issues in-
volved demand,supply,pricing,and
financing.
Another study dates back to ex-
perience with a hydro facility with the
World Bank for the Philippine govern-
ment.My work involved reviewing the
financing requirements,making sure
that there was a need and that the
financing was in the interest of the
Philippine government and par-
ticipants.
Another study was in the Upper
Peninsula Power area.The issue there
was over the need for a large coal-fired
unit which tied together with some
mining activities.
I have had direct experience,for-
tunately dated,in Iran with the govern-
ment of Iran,and I was part of an
economic planning group to decide
amongst some hydro,nuclear,and gas
units that were needed in this rapid
growth economy.
I directed part of a world energy
study which was sponsored by about
50 major energy companies.I obtained
an insightful understanding of the
energy markets in the Pacific region,
and in particular the demands for
energy in Japan and Korea,which
relate to potential outlets for Beluga
coal.
A more recent study of another large
project is the marketing of gas for the
largest potential synthetic gas plant in
the United States.I have conducted
similar studies,with a financing deci-
sion orientation for one of the largest
oil companies in the United States.
Question:Which of those projects .
most closely resemble the situation at
Susitna?
Dr.Rohan:Well,let me describe
which resemble and why.The Canadian
study is similar on the market side
because of similar market conditions.
The economic choices relate to those
in the Wisconsin study where you are
really going through the tradeoffs and
financing of gas,coal,and nuclear.In
the Philippines,we evaluated the ques-
tion of direct financing of a hydro facili-
ty.The study for the Philippines related
to the kinds of guarantees and financ-
ing mechanism for the World Bank in
funding the proposed dam.Some of
the social issues are very similar to
some work which I did for oil com-
panies and their policy in synthetic fuel
development in the Rocky Mountain
area.
Question:Will you elaborate on the
commonalities?
Dr.Rohan:Let me describe some of
the issues.The Canadian study really
looked at one of your key questions-
what are your markets going to look
like in the future?What will be the de-
mand for power to be produced by the
Susitna dams?How elastic to price
would be the markets and how would
the markets change as you added the
facilities?The next kind of question is
really of mix of power plants.Given the
need,what is the optimum combina-
tion of mix of power units that really
can satisfy the need?
Question:Have you encountered a
situation where the choices before the
public were not all centralized choices
like coal,hydro,and nuclear?
Dr.Rohan:Yes,in the Wisconsin
situation.A real choice,and a creative
strategy developed by utilities,was to
focus on ways of moderating demand.
"...in the Wisconsin
situation...a creative strategy
developed by utilities was to
focus on ways of moderating
demand."
Question:How much were they able
to reduce demand?
Dr.Rohan:When I did the work in '74
or '75,the utilities were projecting
growth of about 7 %.*One of the real
findings of the study was that we pro-
jected growth to be substantially less.
The utilities cancelled several power
plants which they were planning to
build,and they were able to meet de-
mand with substantially less new
capacity.They were able to cut the ex-
pected incremental growth in half.
Question:Are there other examples
you could expand upon?
Dr.Rohan:Another was in Con-
sumer's Power region.A lot of the
strategy on that study came back again
to markets for power from the very,
very large power unit.The amount of
money involved in the construction of
one plant was several billion dollars.
We tried to assess future markets in
relationship to their construction
schedule.Basically it turned out that
through detailed market analysis,the
need for power would not develop as
rapidly as projected.
A study that really related to one of
"Editor's Note:Initial forecasts trom the Institute of
Social and Economic Research (ISER)project annual
growth rate over the next 20 years to average 4.5%a year
for the Alaskan railbelt.
your questions about alternatives has
been prepared in conjunction with the
Beluga coal area.I was involved in a
client confidential study (sponsored
mainly by Japanese firms)to assess
the markets for Beluga coal exported
to Japan,Korea,and California.They
were trying to get an assessment of the
competitive role of Alaskan coal,and
how it would fit into Japanese,Korean,
and Californian markets.This ties in
with how you work through alternatives
on Susitna.A critical component will
be-and part of the Battelle study will
certainly show-the cost and cost
structure for coal in the Pacific region.
Question:What knotty problems
have you encountered on other
hydroelectric projects?
Dr.Rohan:I find very often the really
knotty questions can be broadly
classified into two problem areas:
1)decision criteria for choosing
hydro
2)future markets for electricity.
These decision criteria are in their
essence a statement of values of the
citizenry of the region,and incorporate
a tradeoff between economics and en-
vironmental and political concerns.
The really knotty area comes down to a
statement of these values,and this is
not defined in purely direct cost terms.
For example,if we use as criteria,
the minimum cost,the decision is
usually in-favor of hydro or nuclear;
however,frequently overriding these
cost considerations are other con-
cerns.For nuclear,there is the problem
of waste disposal and proliferation;for
hydro,its impact on fisheries and
wildlife.Even in estimating costs,there
are two sides to the coin.There is the
side that shows the direct cost of
power,but as important is the oppor-
tunity cost of not having reliable
power.The decision is a tradeoff of
values-direct cost,indirect cost,and
environmental and political concerns.
"The really knotty area
comes down to a statement
of these values,and this is
not defined in purely direct
cost terms."
In planning for future capacity,the
principal uncertainty is usually'in
estimating the future markets for elec-
tricity.Approaches to estimating de-
mand can result in different answers.
I have been involved in some work in
one western state where it has been,I
suspect,something of a game in which
political viewpoints are expressed
r
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i
"""I
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,,,,,..
i
through a demand methodology.The
methodology is adapted them to project
a set of personal values.What happens
is that rather than saying we are for or
against active conservation,pro-
ponents and opponents have special
methodologies that predict low de-
mand or high demand,depending upon
their political view.The level of demand
in turn influences the neled for,and
choice of power units.··
"I have been invollved in
some work in one ""estern
state where it has been,I
suspect,something of a
game in which pCllitical
viewpoints are ex~.ressed
through a dem,and
methodology.'The
methodology is adal)ted then
to project a set of personal
values."
Question:Do you see that happening
on the Susitna issue?
Dr.Rohan:I am concelrned about
this,although the ISER work on de-
mand appears to be professional and
objective.All parties must agree that
the best forecast can only ,give a range
of probable demands,rather than a
most likely scenario.
This thought process was exactly
what we needed on a Minnesota case.
A group of farmers attending hearings
indicated that there was no need for in-
cremental power.(A latent reason was
tlleir desire not to have power lines
built through their farm lands.)In this
case,each group had to agree on a
range of likely forecasts and then the
impact to the farming community if it
didn't have adequate power.
Question:Can you articulate a
number that corresponds to the cost of
not having power?
Dr.Rohan:Yes,there is some very in-
teresting research going on currently
at EPRI (Electric Power Flesearch In-
stitute).It depends on the class of
customers.The loss of power impacts
each class differently.
For example,if New Yorlk City had a
blackout,you have some very high
social costs-robbery,thefts and mug-
gings during the blackout period.There
"Editor's Note:The same basic methodology that the
Institute ot Social and Economic Research (ISER)is using
is being increasingly used by utilities and government
agencies in other places across the country because it ex-
plicitly identities and accounts for the uses to which elec-
tricity is put.
have been some estimates made that
the cost of not having reliable power is
something like three to four times the
normal cost,i.e.,the normal rate
residential customers pay.It is even
slightly higher on a commercial
building because loss of power
disrupts the whole work environment.
The most severe economic loss is on
industries,such as the classic
aluminum smelter,where the impact of
not having power is to shut down pro-
duction.It might take three to four days
to get the smelter back in operation.
Depending on the specific mix of
customers,it can be four,five,or six
times more costly than the normal
rates.
The issue really comes down to what
is your mix of customer groups?The
research to date indicates that there is
a point where if you underbuild you
have some severe costs.It usually
comes out slightly in favor of over-
building.
I think that the real knotty question
is the question of values.This is the
tradeoff which people make between
economic costs and their assessment
of the ecology and the environment in
which they live in Alaska.
Another factor on the Susitna pro-
ject is financing.If you obtain tax-
exempt financing,it will driive the
economics in favor of a capital inten-
sive project like the Susitna dam
because you have access to less costly
money.Whereas if interest costs are
high,the less costly alternative is one
which has higher operating costs.That
would make the coal or gas unit com·
petitive.Financing will playa role in
the choice between hydro,coal or gas.
Question:You have experience with
the question of industry's potential use
of a new energy source and whether or
not to add that new energy source.
Could the existence of Susitna en-
courage industrial activity in Alaska,
particularly heavy industry such as
aluminum smelting?
Dr.Rohan:Yes,but I don't think you
will see that happen.The reason is that
your rates will be substantially higher
than other alternatives for the
aluminum industry.And when you look
at your growth scenario (the forecast
done by ISER),you'll probably see that
the major share of the growth is in the
residential sector.The other growth is
commercial and this is related to servo
ice activities and government employ-
ment.I think ISER forecasts show
modest industrial growth.I have some
serious doubts whether Alaska could
attract a smelter because (based on
bond financing),your cost of electricity
would be too high,at least in the next
15 or 20 years.Some of the developing
countries are able to obtain very inex-
economics/page 11
pensive financing through the World
Bank,and because they obtain lower
financing costs,their electric costs
will probably remain less costly than
the Susitna project.You may have in·
quiries by the aluminum industry (and
they certainly will inquire about your
rates).I have my doubts about whether
it would be any more serious than infor-
mation gathering.This is at least true
for the next 10 to 15 years.
Question:Do you see it happening
beyond 10 years?
Dr.Rohan:I have been giving serious
thought about electric demand projec·
tions in the Railbelt region.My analysis
indicates that the use of oil for power
generation will decline over the next 10
years and beyond.Your oil export
revenues make it much more econom-
ically attractive to export oil than to
use it for power generation.For natural
gas,I don't fully understand the Kenai
Peninsula situation,although I under-
stand adequate gas to go 15 years or
so.Gas as an energy source competes
in the industrial heating market,so it is
priced on BTU basis comparable to
crude oil.Probably as long as you have
gas reserves,they will be used in home
heating and some industrial use in the
Anchorage area.
In 20 or 25 years from now,when the
Susitna dam would be in operation,you
may experience a change in the rail belt
energy market,with gas becoming in
short supply.In this timeframe,you
may see a conversion to electric heat.
My calculations indicate that the
heating market could in the long run be
the largest single market for electricity,
generated by the Susitna dam.
"The research to date
indicates that there is a point
where if you underbuild you
have some severe costs.It
usually comes out slightly in
favor of overbuilding."
Question:Have you encountered
public values against electric heat?
Dr.Rohan:Yes.There is usually a
pro-environment group that argues in
cogent manner that electricity is a
higher form of energy.I can understand
this argument.It centers around
generation of electric heat from a fossil
fuel.Take gas as an example.Burning
gas in a power plant generates elec-
tricity,but also results in a loss of
about two thirds of the energy as waste
heat.Legislation could be proposed
economics/page 12
that prohibits fossil fuel generated
electric heat because it wastes energy.
But if gas or oil are not economically
available,then there really are very few
choices other than electric heat.
Question:Could you elaborate?
Dr.Rohan:I think the Alaska situa-
tion is going to be different from that in
the Lower 48.The argument,and it pro-
bably is a valid argument,is that if one
generates hydroelectricity,it can be
transported over a network and then
can be used to replace other energy
forms.This is true providing you have a
network and other markets for electrici-
ty.In more remote locations,in par-
ticular Alaska,you neither have an in-
tegrated network nor another market
area to receive excess power.
"Legislation could be
proposed that prohibits
fossil fuel generated electric
heat because it wastes
energy.But if gas or oil are
not economically available,
then there really are very few
choices other than electric
heat."
Question:Some say that
Washington State has developed bad
habits of energy use and home con-
struction because of the abundance of
cheap hydroelectric power.Would you
comment on that?
Dr.Rohan:What has happened in
Washington which resembles the
Susitna situation is that they achieved
inexpensive hydroelectricity mainly
through inexpensive bond financing.
The result on a BTU's heating basis
was that most of the homes in the
Washington area were electrically
heated.On a per customer basis they
use about twice the national average,
and the reason for this high usage is
electric heat.What is happening now is
that there are very few locations in the
Northwest where dams can now be
built.The marginal unit for new power
is nuclear or coal,each of which are
substantially more costly than the
original hydro facility.The addition of
more costly power sources results in
escalating the rates which gives
customers economic incentives to
start a switch from electricity to gas,
and to insulate.
Question:In your estimation,did
Washington State develop bad habits
of energy use?
Dr.Rohan:It depends on your defini-
tion of bad-the consumers purchased
the least costly form of energy
available to them-is that bad?From
an economic efficiency viewpoint if
rates had reflected the real economic
values for electricity,the consumers
may have made different decisions.
Question:Will you expand on that?
Dr.Rohan:For example,in the past,
it wasn't economically attractive to in-
sulate your home,and now it is becom-
ing very attractive to do so.In the
Lower 48,companies are installing,as
an example,control computers for
monitoring lights in buildings and this
reduces consumption.These conserva·
tion businesses are prospering and
creating new jobs.This might be part
of the overall strategy-to exploit
some of this conservation technology
in combination with the Susitna pro·
ject.
The citizenry of the State of Wiscon-
sin is very pro environment.When we
were thinking through the kind of
business strategies for the utilities in
Wisconsin,conservation coupled with
moderated expansion seemed to make
good sense,and I think that this policy
has worked well for them.Conserva-
tion is beneficial to the utilities
themselves as it allows them to build
power facilities in a slightly more con-
trolled environment.
The utilities have also developed a
rate structure that encourages more ef-
ficient use of power generating facil-
ities.That strategy recognizes that
there are certain times of day and year
that it is more costly to generate elec-
tricity.Their rates give economic incen-
tives to customers to moderate usage
during these peak periods.
~:.j
"""I
environment/page 13
Intervievv 3
Dr,A,Starker Leopo d
,....
1""'
A.Starker Leopold,a nationally recognized
zoologist,has had a number of experiences
in Alaska since the 1950's.At that time,he
coauthored the book Wildlife in Alaska,
which discusses some of the general eco-
logic problems in th,e State (the decrease in
caribou and the increase in moose and the
basic causes for both).
Later,Dr.Leopold acted as an advisor on
several major project proposals-the Ram-
part dam proposal in the 60's and the U.S.
Forest Service timbl3r sale to Champion In-
ternational in SouthHast Alaska in the 70's.
Son of conservationist Aldo Leopold,who
some call the "fathl3r of the environmental
movement,"Dr.Leopold has advised on a
number of issues to the Secretary of the In-
terior and the National Park Service.
Since 1939,he has published over 100 ar-
ticles and books,including several on Alaska
wildlife and conservation issues.
Question:I understand that you have extensive ex-
perience in Alaska.One of those experiences was in
evaluating the Rampart dam proposal in the 60's.Will you
elaborate on that experience?
Leopold:I have written several papers*on that subject,
and I can send you those;then at least you will have my view-
point in print.I would be glad to discuss it with you right
now,too.Construction of the Rampart dam would have been
a major catastrophe in terms of Alaskan natural resources.
The Susitna dam looks like a very good bet to me,whereas
the Rampart was a holy terror as far as everything it would
have done to the Alaskan environment.
'Editor's Note:Copies of Leopold's papers are available through the Public Participa-
tion Office of the Alaska Power Authority_
L "Electric Power for Alaska,A Problem in Land-Use Planning,"A.S.Leopold,East
African Agricultural and Forestry Journal,June 1968.
2."Alaska Dam Rampart Would be Resources Disaster,"A.Starker Leopold and Justin
W.Leonard,Audubon magazine,May -June 1966.
3."Effects of the Proposed Rampart Dam on Wildlife and Fisheries,"1966,by A.
Sfarker Leopold and Jusfin W.Leonard.Thirfy-First North American Wildlife and
Natural Resources Conference,March 14,15, 16,1966.
4."Effects of Land Use on Moose and Caribou in Alaska,"A.Starker Leopold and F.
Fraser Darling,Eighteenth North American Wildlife Conference,March 9,10, 11,
1953.
environment/page 14
Dr.Leopold reviewed the Rampart Dam proposal for conservation groups in the
1960's and strongly recommended against its construction.
...~...--o
~--66---~
"Now we are paying close
attention to,and trying to
understand better,what
might happen downstream
from the dams."
Question:How did you become a
part of the team that came to Alaska to
evaluate the Rampart dam proposal?
water coming through those dams and
down the channel does not adversely
affect the survival of the young salmon
in that area in the river.
Make sure also that there is enough
water downstream to flood the Susitna
delta so that it is maintained as water-
fowl habitat.It is a very important
waterfowl area.
All of these objectives look feasible
to me.I can't see any insolvable pro-
blems in managing this whole opera-
tion with fairly modest adverse effects
on wildlife and fisheries.
STATUTE MILES
o 50 100 200 350,E=3 e--=!
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bears,I imagine,and a few lesser
species,but there are no waterfowl
that nest in that particular area.The
area to be inundated would not result
in a large scale loss in terms of the
total wildlife values in Alaska.In other
words,the upstream effect of those
two dams on wildlife would be minimal.
I am assuming that if the dams are
built that the timber will be stripped
out so that they are clean lakes and not
cluttered with floating junk.
Unharvested timber coming up off per-
mafrost and floating to the top could
become a trap for caribou,for example.
Caribou swim freely back and forth
over big lakes.But,they could easily
become tangled up in floating junk or
windrowed timber.
Now we are paying close attention
to,and trying to understand better,
what might happen downstream from
the dams.The other tributaries of the
Susitna are very important indeed in
salmon production.The run of kings,
for example,that people catch in Cook
Inlet near Anchorage,come out of this
area.We want to make sure that
whatever the regime is,the flow of
"...The Susitna dam looks
like a very good bet to me,
whereas the Rampart was a
holy terror as far as
everything it would have
done to the Alaskan
environment."
Question:Will you elaborate on that
last comment?
Leopold:You bet.The Rampart dam,
if you remember the geography of that
proposal,would have created an enor-
mous lake,bigger than Lake Erie,
which would have flooded the Yukon
Flats all the way to the Canadian
border.That big,flat marshy area on
either side of the Yukon River is one of
the major production areas for water-
fowl in the whole continent.The loss of
waterfowl that would have resulted
from the inundation of that area would
have exceeded all of the habi~at that
has been restored since 1934 when the
duck stamp bill first went into effect.
Now that is pretty serious business.
Additionally,there is a salmon run in
the Yukon that goes all the way up into
Canada past Whitehorse;that is the
longest salmon migration in the world.
Indians all along the upper river are
dependent upon those salmon.To
build a high level dam at Rampart
would simply have eliminated the
whole run.There is no way that you can
get salmon up and over dams and get
the little ones back down through a
lake as big as Lake Erie.They couldn't
find their way out.So,the salmon
would have been a total loss.Addi-
tionally,there are many other types of
wildlife that are abundant and impor-
tant in that flat area,including moose
and bear in particular.These obviously
would have been eliminated.
Compare this with Susitna.Although
the dams are several hundred feet high,
the impoundments are very narrow;
they do not inundate any wide alluvium
or riparian zone that is important for
many other types of wildlife.And,most
interestingly,there is no salmon run in
the upper Susitna River.The salmon
are stopped by the Devil Canyon which
is simply too steep and too rough for
them to make it up.Therefore,there
would be no salmon loss there.And the
actual area to be flooded by the two
dams is very modest indeed compared
with the size of the Rampart proposal.
There will be some loss,of course,of
habitat for moose.There are 3,000
moose in the upper Susitna basin,and
part of those clearly would be dis-
placed.There would be some loss of
environment/page 15
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Leopold:I started out by telling you
that Frank Fraser Darling and I spent a
summer up there about "1951 or '52
travelling allover the territory looking
at some of the ecologic problems.On
that basis we wrote the book Wi/dlife in
A/aska.*Although I have not done per-
sonal research in Alaska,I have been
involved in this general recon-
naissance sort of thing.Wh,en the Ram·
part dam proposal came up and looked
like it was going to be seriously con-
sidered (and of course Senator Gruen-
ing was pushing it ve!)'hard)an
organization of conservation groups in
the Lower 48 pooled some money and
sent a team of about six or seven of us
up to Alaska to look more critically at
the Yukon and the Yukon Flats which
would be inundated by ttlle Rampart
dam and to report on what would be the
effect of this dam.If it was indeed bad,
which it proved to be,then we would
give them some factual ammunition to
use in fighting it in Congress.The
Wildlife Management Institute,the
Wildlife Society,the Sierra Club,the
Wilderness Society,and several others
were involved.The leader of this group
was the Dean of Forestry at the Univer-
sity of Michigan.His name was
Stephen Spurr.Steve did some very
clever politicking,I thought Instead of
quietly gathering informa11ion about
what a horror this dam would be,he
went straight to Senator Gruening and
told him what we were finding out,
what sorts of information we were go-
ing to put into our report,and that the
total effect was going to mal<e Rampart
look pretty bad.Gruening,who like any
sensible politician didn't want to put
something up to a vote and have it
voted down,could begin to see that
this proposal was liable to be defeated
in Congress and,therefore,he quietly
withdrew his support for the Rampart
dam and got interested in something
else.
"I am assuming that if the dams are built that the timber will be stripped out so
that the lakes are clean and not cluttered with floating junk.Unharvested timber
coming up off permafrost and floating to the top could become a trap for caribou.
Caribou swim freely back and forth over big lakes.But they could easily become
tangled up in floating or windrowed timber."
-S.Leopold
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Question:What conclusions were in
your report on the Rampart dam pro-
posal?
Leopold:One of the thin,gs that we
had to say in reporting adversely on
Rampart was that the State of Alaska
needs power.But they don't need the
fantastic amount that would have been
created by the Rampart dam way the
hell up there in the wilderness and a
very difficult job of getting it down to
where it was needed.There were many
sites closer to the centers of need-
meaning Fairbanks,Anchorage,and
Juneau-in which smaller hydro
developments could and should be
developed,and one of them that was
•Wildlife in Alaska discusses some of the general
ecologic problems in Alaska:the decrease in caribou and
the increasing numbers of moose and the basic causes for
it.The book was originally published by Ronald Press in
1963 and was recently republished.
-named Susitna.Hence,when the Ram·
part was abandoned,then the atten-
tion,very properly I think,came back to
a much more sensible program,namely
the Susitna hydro.
Question:Were there alternative
hydro sites that your group recom-
mended be looked at?
Leopold:Yes,there was one at the
head of the Yukon River in Canada.As I
remember,it would have diverted the
upper reaches of the Yukon River (this
would be just the tributaries way up far
above Whitehorse)into the Taiya River
and from there run through a 25-mile
underground power tunnel to generate
power at tidewater at Skagway.
Question:Besides Susitna,did you
name any other hydro sites iin the
vicinity of the rail belt by Anchorage
and Fairbanks?
Leopold:No,I don't think so.We
talked about coal,of course.It was
known that there were some big coal
deposits,but it was such a fantastic
opportunity for hydro it seemed a much
better bet to go for a hydro project
such as the Susitna.If there were
others that we named,I don't
remember and that was several years
ago.
Question:What knotty problems
have you encountered on hydroelectric
projects?
Leopold:I have already mentioned
the one that concerns me here.I want
to be sure about what happens down-
stream.You see,once you build a dam,
you can then release water in different
amounts.You can also release water at
different temperatures,depending on
environment/page 16
whether you draw from the bottom of
the lake or the top.
You can sit and look at the Susitna
all you want,but it is not going to tell
you how those little salmon will fare
when the river is running deeper in the
wintertime,for example.You are clear-
ly going to be holding water in the sum-
mer and letting it out in the winter.
These are things in which you have to
use your best judgment,and to this ex-
tent,I am urging that we take advan-
tage of all of the experiences that have
been had in the damming of glacial
streams in Scandinavia and the USSR
and in Canada.I've looked at some of
the similar dams in Argentina,but they
are not quite the same.I am sure there
must be some in Canada,and I know
there are others in Russia that are not
unlike the situation here.
Hopefully,there are ways of getting
at this information and to find out what
they have learned.What happens
downstream when you dam a glacial
stream and hold the water through the
summer and feed it out in the winter
when the normal flows are low?
Somebody must have some good infor-
mation on that.I am hoping we will get
as much as we can to prognosticate
what the effects of this dam may be.
Question:Would you elaborate on
some of your experiences in Alaska?
Leopold:Yes,going way back to the
beginning,that very first trip in the ear-
ly 1950's was occasioned by the fact
that caribou were known to be decreas-
ing rapidly.The Fish and Widlife Serv-
ice (this was before Alaska was a state,
of course)was in charge of the wildlife
program.They considered that one of
the major causes of the decrease in
caribou was excessive numbers of
wolves.So they had a very large-scale
wolf control program:some poisoning
and some shooting from airplanes.
This was going on in the Brooks Range
and generally throughout Alaska.They
were killing several hundred wolves a
year.
Some of us wondered whether this
"You can sit and look at the
Susitna all you want,but it is
not going to tell you how
those little salmon will fare
when the river is running
deeper in the wintertime ..."
was indeed the basic cause for the
decrease in caribou.Obviously,wolves
eat caribou,but there have been wolves
eating caribou there for a million years.
What we were really looking for was
any possible changes in the nature of
the countryside,the habitat in which
the caribou lived.We found one that
was certainly important,namely that
since the coming of the white man,
really since the Klondike gold rush,
there had been an enormous increase
in the number of forest fires,accidental
and deliberate,that had burned the
sparse spruce forest and the under-
story of lichens which constitute one
main winter forage of caribou.
A man from Yale Forestry School by
the name of Lutz had made a careful
survey of fire history in Alaska.He
estimated even at that time that
somewhere around 85%of the white
spruce forest in Alaska had burned in
the previous half century and that
these fires pretty much destroyed the
value of these woodlands for caribou
winter range but conversely made ex-
cellent moose range by stimulating
willows,aspen,and birch.Those are
the principal winter foods of the
moose.
This seemed to have some relevance
in the sharp decrease in caribou and
the concurrent increase in moose in
Alaska.I think there were other factors:
hunting by Native people,and the sud·
den availability of high-powered rifles.
All of these things were involved,but
those basic changes in the habitat of
the large part of Alaska I still think was
important.Nowadays,with somewhat
better fire control,the caribou are
holding their own,but they have never
increased back into the millions that
occurred originally.That was the main
thrust of our initial survey up there in
the 1950's.
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"There will be some loss of habitat for moose.There are over 3,000 moose in the
upper Susitna basin,and part of those clearly would be displaced."
-S.Leopold
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Question:What more Irecent ex-
periences do you have in th'e State?
Leopold:A more recent program in-
volved an appraisal of a timber sale on
the Tongass forest south of ,Juneau,in-
cluding Admiralty Island and some of
the adjoining mainland.The timber
sale had been made by the Forest Serv-
ice to U.S.Plywood,which subsequent-
ly became Champion International.The
sale provided for 8.6 billion board feet
of lumber and specified that a mill
would be built south of Jum~au to pro-
cess this lumber.Some of it would be
sent to Japan.
The lumber company set up a small
committee of consultants,of which I
was one,to advise them on how to
operate this timber harvest with the
minimum adverse effect on the en-
vironment.We all went up there with
enthusiasm and optimism,and we
were eager to work with the company
in developing a good plan to save as
much as we could of the bear,deer,
salmon,and other wildlife values.
One of my recent PhD's,by the name
of Reginald Barrett,went up to Juneau
and worked for a whole year in this sale
area.We began to realize thatJhe
removal of 8 billion board feet of timber
would practically take every stick in
that whole area,and there would be no
shelter left for wildlife of any kind.Cer-
tainly the deer population would col-
lapse,and many of the people,local
people including some of the Indian
tribes like residents of Angoon,die pend
upon those deer for part of their winter
food.The bear population and many
other animals would be adversely af-
fected.
In other words,we had to tell the
president of Champion International,
that in our opinion the Forest Service
had over sold that timber,in no way
should 8 billion board feet be removed
from that area,and we simply could not
advise him on how it could be done
without adversely affecting wildlife.As
you may remember,there was a lot of
litigation between the Sierra Club and
the Forest Service and the company.
This led to reconsideration by the
courts of the whole problem and finally
the whole project was dropped.
Question:Are there any other pro-
jects that you know about that closely
resemble the situation on the Susitna?
Leopold:No,I can't really say that I
have ever been on one just like this
one.We've done quite a bit of work on
impoundments here in California in the
Sierra Nevada,effects on trout,effects
on deer,and so on,but they are quite
different really.
geotechnical studies/page 18
Intervievv ..
Dr.Andrew H,Merritt
Dr.Andrew H.Merritt,a specialist in
engineering geology and applied rock
mechanics,has worked on geotechnical in-
vestigations,design,and construction of
hydroelectric projects throughout the world.
He has also been involved with tunneling
projects for water conveyance and sewerage
disposal systems and the development of
underground excavations for petroleum
storage.
On projects like Susitna,Dr.Merritt has
worked as a consultant for engineering com-
panies,contractors,owners,and lending
agencies such as the World Bank and the In-
ter American Development Bank.
Question:What experience do you have in Alaska?
Merritt:Most of my work is in hydro,tunnels,and
underground chambers.Since completed engineering pro-
jects of this nature are in short supply in Alaska,I have not
had the opportunity to work in this area.My experience in
northern climates consists of 3 years in Labrador,Canada,
during the development of the Churchill Falls Hydroelectric
project and more recently as a consultant to B.C.Hydro and
B.C.Railroad in British Columbia.
Question:In your particular field,what are the other pro-
jects that you've worked on that have similar kinds of pro-
blems and issues to Susitna?
Merritt:We have not defined all the possible problems at
Susitna yet because the investigation program is still in pro-
gress.That is the purpose of the ongoing feasibility studies.
If you have read the External Review Panel's report,we
highlighted some of the major areas that were of interest to
us at this particular time.From my point of view,in the
geotechnical field,I am primarily concerned about the
general quality of the rock in the underground excavations
at the Watana site and also possible seepage away from the
reservoir through the buried preglacial valley on the right
abutment.
I did not see anything of an unfavorable nature at the
downstream site at Devil Canyon.The geologic conditions
looked pretty straight forward at this particular stage in the
investigation.
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We have to realize that all the
material available to date (February
"1981)is of a prefeasibility level of study
and as such is not complete.Our role is
to ensure that the studies being done
at present will provide answers to the
major geotechnical,engineering,and
environmental aspects of the project.
H •••most of the challenges
that we recognize at present
have been successfully
engineered onllther
projects."
Question:What other projects do
you know about that have similar pro-
blems and issues?
Merritt:It is hard to compare Susitna
with any other job elsewh,ere because
no two projects are exactly the same.
Susitna has aspects very similar to
other projects that I have worked on.
For example,the underground power-
house at Susitna is neither larger nor
deeper than many others.As a matter
of fact,it is fairly typical of eight or ten
other underground chambers that I
have worked on.
We won't know how typical or unique
the conditions are at Susitna until the
exploration program has been com-
pleted in 1981.
With respect to the dam at Watana,it
is on the order of 250 meters (800 feet)
high,which is a major structure.But it
is not without precedent.I have worked
on both concrete arch and fi II-type
dams that are nearly as high.
Considering the seismic activity
prevalent in Alaska,this aspect of the
design will receive the detailed atten-
tion that it deserves.I have one job in
Honduras where the Power Authority is
bui Iding an arch dam 220 meters (715
feet)high.It was considered to be in a
fairly high seismic area;however,
analyses are available to design a safe
dam under such conditions.
There is a project presently under
construction in Guatemala which con-
tains a rock fill dam about 130 meters
(423 feet)high.The earthquake condi-
tions in Guatemala are much more
severe than are believed to exist at
Susitna.This dam was also carefully
analyzed for seismic effects and the
engineers,owners,and international
lending agencies are satisfied that the
structure is completely safe.
In summary,at this particular time I
don't see anything unique about the
Susitna project.There is no doubt that
it contains many challenging and in-
teresting aspects,but most of the
challenges that we recognize at pre-
geotechnical studies/page 19
Shown here is the construction of the underground powerplant at Oroville Dam in
California.
Underground powerhouses are proposed at both Watana
and Devil Canyon.The cost analysis of underground vs.
surface powerhouses showed that underground was
more economical because shorter tunnels can be used
and because there is no need for the extra cost of struc·
tures at ground level.
geotechnical studies/page 20
sent have been successfully engi-
neered on other projects.
Question:What kinds of knotty prob-
lems have you encountered on hydro-
electric projects?
Merritt:Some of the major problems
that have occurred with dams or reser-
voirs happen with those structures
located in very pervious rock founda-
tions,such as karstic or cavernous
limestones.These pervious rocks do
not exist at Susitna.Other problems
have occurred in reservoirs or
abutments with slope stability prob-
lems.The topography at Susitna ap-
pears to preclude any slope stability
problems.
Other knotty problems include the
evaluation of the seismicity of a site.
As you may be aware,there has been a
great deal of attention given to
seismicity over the last 5 to 10 years for
the design of dams.Many of the pro-
jects being built or in the design stage
in Central and South America are
located in active seismic areas.As I
said earlier,the jobs that I am working
on in Honduras,Guatamala,and in Col-
umbia are in seismically active areas
and the designers are all using the
most modern equipment to measure
the potential earthquake hazards and
the most up-to-date analytical design
tools to ensure a safe structure.All
similar methods and techniques will be
used at Susitna.
A third kotty problem might include
the inevitable unknowns associated
with underground excavations such as
chambers for powerhouses and long
tunnels.The exploration program as
planned for Susitna will go a long way
in determining the unknowns and
reducing such contingency items.The
borings and geologic mapping should
define the geologic conditions in the
proposed underground chambers with
a high degree of confidence.I am work-
ing on three underground powerhouses
at present.Two are proceeding
smoothly.The third one is having
serious problems of a geologic nature.
It is interesting to note that this last
one had very little preconstruction ex-
ploration because of a lack of funds.
Fortunately,that doesn't happen very
often and it is not the case with Susit-
na.
"Our role is to ensure that
the studies being done at
present will provide answers
to the major geotechnical,
engineering,and
environmental aspects of the
project."
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Another interesting aspect at
Watana,as I mentioned before,is the
old river valley on the right abutment.
The river at one time in the geologic
past swung away from the present
valley just upstream of the Watana site
and cut across the plateau on the right
side and exited just downstream in
Tsusena Creek.The former course of
the river deeply eroded the bedrock.
This channel was then backfilled with
what I assume to be glacial deposits
and alluvium.The bottom of this rock
valley lies below maximum pool level
of the proposed reservoir.We have to
be sure that the water doesn't enter
this old valley and make an end run
around the dam.This interesting
aspect is going to be given a large
amount of study in thE!feasibility
phase.It is a problem that I have run
across in projects in Ecuador,Argen-
tina,and Canada where we have similar
geological terrain.
On another matter,I do not expect to
have any particular problems with bar-
row material for the Watana darn,even
though the volumes are quite large.I
think that the glacial deposits and
bedrock will provide completely ac-
ceptable materials for construction.
Question:What involvement will you
have in evaluating seismicity for the
proposed dams?
Merritt:The aspect of seismicity that
I would generally get involved in is the
assessment of possible faults and how
large the design earthquake could be.
I will add that the Alaska Power
Authority is expending a great deal of
effort to resolve the seismic question.
The techniques include measuring
micro earthquakes,performing de-
tailed geologic mapping,and eval-
uating the historical earthquake
record.As I see it,you are using techni-
ques and methods accepted Ithrough-
geotechnical studies/page 21
out the world in the profession.
"It is hard to compare
Susitna with any other job
elsewhere because no two
projects are exactly the
same.Susitna has aspects
very similar to other projects
that I have worked on.For
example,the underground
powerhouse at Susitna is
neither larger nor deeper
than many others.As a
matter of fact,it is fairly
typical of eight or ten other
underground chambers that I
have worked on."
This sketch shows the underground powerhouse at Churchill Falls in Labrador,C.mada.II
has more installed capacity than what is planned for Walana.
In cold climates and earthquclke country,underground powerhouses have severa,I advan-
tages:they are protected from weather problems at the earth's surface and are inhere,nUy
more stable in earthquakes.
-taken from Heritage of Powl~r,designed and produced for Churchill Falls (Labrador)Cor-
poration Limited by Cabana,Seguin &Associates Inc.
concerte structures/page 22
Intervievv 5
Mer in D,Copen
Mr.Copen has over 40 years of experience
as a civil engineer with the design and
analysis of about 70 concrete dams and
other concrete structures.For 33 years he
was with the U.S.Bureau of Reclamation,
becoming Head of the Concrete Dam Sec-
tion in 1968.
W~lile with the Bureau,Copen had major
resposibility for numerous large dam pro-
jects,including the Auburn dam in Califor-
nia,one of the longest arch dams in the
world.The Auburn dam is upriver of Sacra-
mento.It is a large concrete structure in a
highly seismic area.Controversy surrounded
its design.
Mr.Copen was also responsible for
evaluating the behavior and safety of all con-
crete dams constructed by the Bureau.He
had assignments on concrete arch and grav-
ity dam problems in India,Thailand,Laos and
Korea.
Currently,Mr.Copen is a private consul-
tant on various projects around the world.He
is also a consultant on two other Alaskan
projects:Green Lake in Sitka and Swan Lake
in Ketchikan.
Question:What experience do you have in Alaska?
Copen:Presently,I am on the board of consultants for
Green Lake dam near Sitka and for Swan Lake dam near Ket-
chikan.During my work in the Bureau of Reclamation,I had
experience in the design phase of essentially all of the pro-
jects that you are now considering in Alaska,including
Susitna.
Question:What projects have you worked on that resem-
ble Susitna?That means,in your case,from the point of view
of a civil engineer.
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Copen:I have worked for the Bureau
of Reclamation for more than 33 years,
during which I was responsible for the
design of Glen Canyon dam,which is
over 700 feet high;Yellowtail dam,
which is more than 500 feet high;Flam-
ing Gorge dam,which is more than 500
feet high;Morrow Point dam,about 470
feet high;and many other smaller
dams.These cover the range of com-
plexities regarding foundation,size,
and local conditions such as cold and
warm temperatures.They also repre-
sent quite a range of designs and sizes.
Question:Other review panel
members referred to dam structures in
Russia but did not know the names,
locations,or other details.Do you
know anything about hydro projects in
Russia?
Copen:Yes,from a recent short arti-
cle in the Denver Post.One of these
structures,I think it is Nurek,is a com-
pleted arch dam 984 feet high.The
other structure,which is under con-
struction,is an embankment-type dam,
which will be almost 1,100 feet high,
(1,099 as I remember the figlure).These
are the largest dams in the world.
Grande Dixence,a Swiss dam,com-
pleted in 1960 or '61,is slighty smaller
-938 feet,I believe.It is a concrete
gravity dam..
Question:When you saild that the
Russian dam was an embankment
dam,is that the same as an earth·filled
dam?
Copen:An embankment structure
can be earth or rock filled,and I'm not
sure which this is.
Question:Were you involved in the
review of any of those dams?
Copen:No.I was in the Bureau of
Reclamation when we received news
reports from Russia,which were
translated and made available to me,
and I have watched the progress of the
dams,but I was not involved in review-
ing them.
"So far as earthquakes are
concerned,we had probably
a more difficult problem at
Auburn than you have on
Susitna."
Question:What kinds of kn01lty pro-
blems have you encountered on hydro-
electric projects?
Copen:The Auburn dam was de-
signed under my supervision complete-
ly.I left the Bureau of Reclamation just
before the contract was awarded for
the foundation treatment,so I worked
only on the design.The river diversion
was also completed before I left the
Bureau.
The problems with the Auburn dam
were largely with seismicity,and we
will have a similar problem on Susitna
with seismicity.At the present time,it
has been recommended by Woodward-
Clyde that provision be malje for
ground accelerations of 40%of nravity,
which can easily be handled in the con-
concrete structures/page 23
crete dam.Now,the thing that caused
the most trouble at Auburn was the
problem of displacement.Displace-
ment in the foundation of Susitna
could occur if an active fault were
found under one of the dams.This par-
ticular problem is being investigated at
the Watana site.
Another problem that will be ex-
perienced will be the problem of
temperature.The very low tempera-
tures are something that have to be
considered and included in the design.
We have the capability of doing that.
Low temperatures result in concrete
shrinkage and thus downstream move-
ment.These movements are controlled
by properly shaping the arch dam.
The third and sometimes the most
important problem is the foundation.
We have to know the anomalies in the
foundation,such as joint foliation,bed-
ding planes,seams,or anything that
might cause a problem of instability in
the foundation resulting from the
pressures that would be applied to the
foundation by the dam.
So again,the major problems are
earthquakes,low temperatures,and
foundation abnormalities.All of these
can be handled with proper design and
construction procedures.
The contracts for foundation treat-
ment and river diversion were com-
pleted.Because of the intense con-
troversy which developed regarding
earthquake magnitudes and displace-
ments,the dam has not yet been con·
structed.I do not believe a schedule for
construction has been established.
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Hoover is a thin arch concrete dam-like what Devil Canyon is proposed to be.
concrete structures/page 24
Question:How do those three prob-
lems on Susitna compare to the range
of problems you have encountered in
your 33 years of experience with the
Bureau of Reclamation?
Copen:I have encountered all of
them.I haven't worked specifically with
temperatures as low as we are ex-
periencing here.However,in the
western part of the United States,we
do have extreme temperatures which
go down to 40,50,and 60 degrees
below zero and will go as high as 100
degrees above zero Fahrenheit.The
range that you are concerned with at
Susitna is in the lower part of this
temperature spread and doesn't in-
clude the higher part.I would say,so
far as temperatures are concerned,that
I've had experience with a much wider
range than will be involved on the
Susitna project.
"So again,the major
problems are earthquakes,
low temperatures,and
foundation abnormalities.All
of these can be handled with
proper design and
construction procedures."
So far as earthquakes are concerned,
we had probably a more difficult prob-
lem at Auburn than you have on Susit-
na.I am presently involved (and have
been for about six years)with construc-
tion of a dam in Taiwan.It is a smaller
dam and has many problems with its
foundation and with earthquakes.We
have successfully designed this struc·
ture,and construction is proceeding.It
is only about 400 feet high but has very
difficult foundation and earthquake
problems.The foundation problems
cover all those that I have already men-
tioned-the possibility of instability in
the foundation and rather wide seams
in the foundation that have to be
treated in order for there to be stability
of the dam.
At the time I left the Bureau,we
knew of 27 faults or shear zones in the
foundation of Auburn Dam.I under-
stand three more were found bringing
the total to around 30,all of which were
accounted for in the analyses and were
treated to make the dam safe.
Comparison of Proposed Devil Canyon
Dam and Hoover Dam
Hoover Dam is about 100 feet higher than Devil Canyon is proposed to be.Both
dams,however,would be almost exactly the same width at the top crest.A surface
powerhouse is shown below Hoover Dam on the left.Underground powerhouses
are proposed for the Susitna dams.
The shape of the reservoirs formed by Hoover Dam and the proposed Devil Can·
yon Dam would be quite different.
Shown here is an aerial view of Hoover Dam and Lake Mead.Notice that the reser·
voir is initially very narrow,then takes a turn to the left and opens up into a broad
expanse of lake.
By comparison,the Devil Canyon reservoir would remain narrow (about Y2 mile
wide)for its entire length of 28 miles.
The total reservoir capacity of Devil Canyon would be about 1/30 that of Lake
Mead.
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hydraulics/page 26
Intervievv &
Jacob H,Douma
Jacob H.Douma,an internationally recogniz-
ed hydraulics expert,served with the U.S.
Army Corps of Engineers for more than 40
years.He was Chief of the Hydraulic Design
Branch in Washington,D.C.and was respon-
sible for the final review and approval of all
hydraulic design and research programs.For
the past 30 years,he has been consulted on
dam projects in India,Pakistan,Iran,Haiti,
Venezuela,Argentina,Canada,and else-
where.
Question:What is your Alaskan experience?
Duuma:I haven't worked on any project to the extent that I
will be working on Susitna.I worked for the Corps of
Engineers and the Bureau of Reclamation for almost 44
years,being in the office of the Chief of Engineers in
Washington,D.C.,for 32 of those years.I had the opportun-
ity to review projects being planned and designed in Alaska
by the Corps'Alaska district.
One project in particular,having to do with a hydroelectric
plant,was the Rampart Dam which only reached the survey
report stage and was not authorized for design and con-
struction.I never saw the Rampart site,nor did I sit in on any
planning and design meetings.I reviewed reports on the pro-
ject that came into the Chief's Office and I attended the
Board of River and Harbor's review of those reports in
Washington.
There is another project in the same category,the
Snettisham dam,near Juneau.The Corps of Engineers con-
structed a tunnel from a lake to a powerhouse.That project
had a very unique problem.A tunnel was driven to tap the
lake well below the water level in the lake.I recall that there
was a lot of debate among tunnel engineers on how the con-
struction should be accomplished.Finally,a method which
was developed and used previously in Sweden was adopted
and proved to be successful.
Another project with which I was involved in Alaska was a
dam near Juneau on Gold Creek which was experiencing
severe erosion of the outlet conduit invert.Recommenda-
tions were made on how to protect the invert against ero-
sion.That is the extent of my participation in Alaskan
projects.
hydraulics/page 27
A flip bucket spillway is much like a giant playground slide with the end curved
upward.This dissipates the energy by dropping the water into a deep pool well
clear of the end of the spillway.
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Question:What other projects are
you familiar with that resemble the
Susitna project?
Douma:I think the projects that
come the nearest to Susitna are the
Mica and Revelstoke dams on the Col-
umbia River in Canada.Mica Dam is
not quite as high as Watana,but it is a
rock and earthfill dam,as Watana is
proposed to be.Revelstol<e is about
twenty miles or so downstream from
Mica.It is an earthfill and rockfill dam,
presently under construction.When
completed (1983)it will be about 600
feet high,which is not too different
from Devi I Canyon.
Both of these projects are primarily
for hydroelectric power,as are the two
dams on the Susitna.
I suspect the hydraulic problems will
be quite similar except for one major
difference.Mica Dam has a low-level
outlet that operates undeir very high
head,consisting of two sets of gates
located in a large diversion tunnel.The
upstream set of gates discharges into
what is known as an expansion
chamber which dissipates about 250
feet of head.Downstream from this ex-
pansion chamber,another set of gates
discharges into the downstream part of
the tunnel.I don't think there will be
anything like that at Susitna because,
as I understand it,most of the water
will discharge through the power
plants and spillways.
"Fish live on air absorbed in
water,but when there is an
excess of nitrogen many do
not survive.On the
Columbia River,several
ways were found to partially
alleviate the problem.
Unless precautions are
taken in spillway design,
this same problem may
occur on the Susitna River
after the dams are
constructed."
Question:Did you work on the
engineering for the Mica and the
Revelstoke dams?
Douma:I worked on the engineering
for Mica dam only.I was a special
hydraulic consultant to CASECO,a
consortium of three Canadian firms
that did the design in Vancouver,B.C.I
was involved for five or six years on the
initial design,model testing,and con-
struction.
Question:Was your role on that pro-
ject similar to your role with the Susit-
na project?
Douma:Yes,I was involved with the
hydraulic design and hydrologic
aspects.CASECO was working for B.C.
Hydro in the same capacity as Acres
now works for the Alaska Power
Authority on Susitna.I was a consul-
tant to CASECO,the engineElrs who
designed the project,not a consultant
to the owner,B.C.Hydro.On the Alaska
project,I am a consultant to the owner,
the Alaska Power Authority,not the
designer.
Question:So your function is the
same,only the client is different?
Douma:Yes,that's right.My function
is the same,which is to be involved
primarily in the hydraulic design of the
structures and the hydrologic aspects
of the project.
Question:Have you had any ex-
perience with the kinds of conditions
that you find in northern climates like
Alaska?(Permafrost areas,glacial
rivers)
Douma:As I recall,my only involve-
ment with the design of projects that
have had cold climates has been in
Canada.The Mactaquac projeclt in New
Brunswick is one,and I am still on con-
sulting boards for several dams on the
Saskatchewan River in Saskatchewan
Province.These projects are con-
cerned with ice problems.I don't know
whether ice problems on the Susitna
will be more difficult than those on the
Canadian Rivers.I assume they will be
quite the same.
Question:What knotty problems have
you encountered on hydroelectric pro-
jects?
Douma:I have jotted down four dif-
ferent knotty problem areas.
First,referring to Mica Dam,one of
the major and most difficult problems
was the question of reservoir slides.
There are some active slides in the
steep mountain slopes just upstream
from the dam site and one question
was whether filling the reservoir would
cause large slides to come down into
the reservoir.
An hydraulic model was constructed
that could test what would happen if
huge slides should occur.This model
was built at the Western Canadian
Hydraulic Laboratory in Vancouver.
The model indicated that under the
worst slide assumptions a large wave
would be generated in the reservoir
which would overtop the dam by 25
feet.We were very much concerned
whether the top of the dam would
erode so rapidly that it would cause the
dam to fail and the reservoir to empty.
Design precautions were taken by pro-
viding toe fills to control the slides and
increasing the dam slopes in the upper
part of the dam,both on the
downstream and upstream sides.The
crest width of the dam was increased
hydraulics/page 28
to 110 feet instead of 50 feet so there
would be less likelihood of dam failure
in the event it should be overtopped by
waves.Fortunately,after ten years the
reservoir has been filled a number of
times and there is no indication of any
slides.
I don't think there will be a similar
problem at Susitna because there does
not seem to be any large,active slide
zones in the reservoir areas similar to
those on the Columbia River.That is
one knotty problem which occurs on
some hydroelectric projects.
"I don't think there will be a
similar problem at Susitna
because there does not seem
to be any large,active slide
zones in the reservoir areas
similar to those on the
Columbia River.That is one
knotty problem which occurs
on some hydroelectric
projects.II
Another difficult problem is the
design of cavitation·free,low·level
outlets and spillways.I have already
described the type of low-level outlet at
Mica Dam which operates very well but
there are a number of dams where dif-
ficult cavitation erosion problems have
occurred.As low-level outlets at the
Susitna dams will not operate frequent-
ly,cavitation erosion in them should
not be a problem.
However,there will be spillway chan-
nels at Susitna in which water will flow
at very high velocities as it drops from
high reservoir levels to the downstream
river bed.There will be serious prob-
lems with erosion of the concrete due
to cavitation,if design and construc-
tion isn't handled correctly.This cavita-
tion erosion of concrete is caused by
high-velocity flow passing over a rough
concrete surface which,in turn,causes
pressures at localized areas to drop
down to what is called vapor pressure
which produces cavitation erosion.
That will be a problem of concern in
designing the spillways for the Susitna
dams.
A third knotty problem is erosion of
the Susitna River channel downstream
of the spillways.One alternative for the
Watana Dam spillway is to provide two
stilling basins for energy dissipation.
These stilling basins will minimize
downstream channel erosion,but they
may have structural problems due to
the high velocity and forces in thejump
action within the stilling basin.
An alternative that was talked about
at our first meeting was to use a flip
bucket.The flip bucket would simply
deflect the water out into the
downstream river channel without any
hydraulic jump action,eliminating the
stilling basin structural problems.
Sometimes flip bucket action causes
deep .and serious erosion in the
downstream river channel.If flip
buckets are considered for the Susitna
dams,a careful analysis will need to be
made of the potential for excessive ero-
sion.Their use may not be feasible.
I have consulted on Tarbela Dam in
Pakistan for five or six years where
serious downstream channel erosion
occurred due to operation of flip
buckets.Spillway flows flipped out into
a rock lined channel which was not as
erosion resistant as engineers thought
and a tremendous deep plunge pool,
over 200 feet deep,was eroded.It was
eroded in a lateral direction to one side
which caused the erosion to approach
the end of the flip bucket structure
causing impending failure of the struc-
ture.Construction of remedial work
over a period of two years at a cost of
approximately $80 million was required
to correct the problem.
A related spillway problem is the
nitrogen supersaturation problem.On
the Columbia River the flow of water
through spillways into stilling basins
resulted in excessive entrainment of
air,causing an excess of absorbed
nitrogen in the water.Fish live on air
absorbed in water,but when there is an
excess of nitrogen many do not sur-
vive.On the Columbia River,several
ways were found to partially alleviate
the problem.
Unless precautions are taken in
spillway design,this same problem
may occur on the Susitna River after
the dams are constructed.If stilling
basins are constructed there will be
greater amounts of air absorbed in the
water and there may be a nitrogen
supersaturation problem with down-
stream fish.
If a flip bucket is used,as Acres has
suggested,the water could be
deflected horizontally into the
downstream river channel and the
nitrogen supersaturation problem
would be minimized.However,if the
flip bucket design results in formation
of a deep plunge pool,then the same
nitrogen supersaturation problem can
occur because air entrained water
plunges deeply into the plunge pool
causing an excessive amount of
nitrogen to be absorbed.
The fourth and last knotty problem I
want to discuss is the environmental
effect in the downstream channel.I
have al ready ment ioned nit rogen
supersaturation which may be caused
by spillway operation.Other en-
vironmental effects will result from the
changed flow conditions in Susitna
River downstream of the dams due to
regulation of the flow by the dams.
Channel configurations may change
appreciably.Whether these changes
have any environmental effect is being
studied.Dr.Leopold thinks that it may
change the erosion and deposition
characteristics of the river in such a
way that river areas where moose feed,
would be reduced.Under present
natural conditions,large floods create
new islands which provide moose
browse.
"The proposed studies will
most likely establish that
reservoir-induced slides
would not be a problem at
the Susitna dams.II
Question:Are those knotty problems
unique to the Susitna situation,or are
those the same problems that you face
in other dam construction projects?
Douma:Those problems are not par-
ticularly unique to the Susitna project.
Reservoir induced slides have occur-
red at many projects,but serious con-
sequences due to dam overtopping by
sl ide-generated waves have occurred at
only a few dams.The proposed studies
will most likely establish that reservoir-
induced slides would not be a problem
at the Susitna dams.
The problem of designing cavitation-
free,low-level outlets occurs at every
high dam which contains a low-level
outlet that will operate for substantial
lengths of time under high heads.This
problem may not be serious at the
Susitna dams because the low-level
outlets would be operated infrequently.
All high dams with high-velocity
chute spillways have the potential for
cavitation erosion of the concrete
chute and excessive erosion in the
downstream river channel.Environ-
mental effects due to nitrogen super-
saturation may occur at any high dam
which has a deep stilling basin,or
plunge pool and a downstream fishery.
Finally,serious environmentalef-
fects may occur in the river channel
downstream of any large dam and
reservoir project due to major changes
in natural river flows caused by
regulated reservoir outflows.
hydraulics/page 29
Cross-section of Devil Canyon spillway
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flip bucket at end
of spillway
DATE DUE
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