the baldwin hills reservoir failure 1987 engineering geology v1

8/16/2019 The Baldwin Hills Reservoir Failure 1987 Engineering Geology V1

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Engineering Geology

24 (1987) 167--172 167

Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands

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i s c u s s i o n

THE BALDWIN HILLS RESERVOIR FAILURE

Walter Hoy e, Los Angeles DWP:

Let me tell you about my involvement at the time of the Baldwin Hills

Reservoir failure. I was studyin g for my f irst promo tio nal exam at the

University of Sou thern California library. I was an en try level engineer at the

Dep art men t o f Water and Power. Well, here I am 22 years later, I am the

Engineer of Design in charge of dam safety. I was concerned then and I am

really concerned now. I am responsible for all of our dams in the city and all

of the dams we have along the 300 miles of aqueduct that bring water from

the Sierras to 3 million people in Los Angeles. I thank Dr. Leonards very

much for giving me a chance to address yo u to day.

As far as Baldwin Hills Reservoir goes, we at th e Dep art ment thin k t he

stress relief fault mov eme nt triggered by the high pressure fluid in jection for

second ary oil recovery was the decisive cause which led to ruptur ing of the

reservoir lining. The sett leme nt in favor of the Dep art men t of $4 million

against the oil companies was reached short ly after pu blication of a paper

that has been men tion ed earlier, "Gro und Ruptu re in the Baldwin Hills", by

Hamil ton and Meehan, and it discusses the mechani sm for t hat stress relief

fault move ment triggered by fluid injection. It may be that everybody here

does no t agree that this was the decisive cause of the failure; however, I am

sure th at everyone will agree tha t this high pressure stress relief did accelerate

the movements along the fault. I am not going to discuss the failure any

further and will go directly into what we have learned from that event.

Firstly, there really is no substi tute for people. We need an experienced

staff to design, operate, maintai n and provide reservoir surveillance. We try

to d o t ha t t hro ugh traini ng and I thin k we are quite successful at it. We also

retain consultants to help us out in areas where we need more experience or

in areas where we have lost key personnel, as happens f rom time t o time. In

addition to people, I think modern equipment helps out. We have since that

time developed a computer-aided system to pull in the data that we get from

the field. As you know, surveyors and hydrographers go out in the field and

gather all this data. It's up to some poor guy in the office to tabulat e it, graph

it and s tud y it, and year after yea r that can be fairly routine . We are com-

puterizing that information and it will be plotted in bright colors that will be

a mechanism to allow supervisors to look at this data and perhaps highlight

red flags more easily tha n th e manu al met hod s used before. It will give these

people more time to stud y the results. I t will also enrich the job so it will be

more interesting. We have almost completed developing our computer-aided

surveillance data plotti ng system and are really looking forw ard to using it.

0013-7952/87/$03.50 © 1987 Elsevier Science Publishers B.V.


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Anot her piece of mod ern e qui pmen t is a supervisory contro l and data acqui-

sition system. This will pull in data f rom all of our facilities thro ug ho ut our

460 plus square miles in the city and along that aqueduct I told you about.

It will supplement the t eleme try system that we have right now. The key

point is that all of this data will be going into a control center 24 hours a

day. We will have peopl e on hand day and night observing this data. There is

a lot of activity going on in inspection and surveillance at the Department.

There is also a lot of wor k being do ne at the State and Federal levels. Things

are very differ ent now than the y were in the decade 1950--1 960.

I previously talked ab out training in-house people, now the people in the

field are also trained and I do not think there is a better example in the his-

tor y of dams of the value of adequately trained field personnel than that

which occurred during the Baldwin Hill failure. Those people not only knew

how to operate valves, the y knew how to operate water systems; they did

not have to consult maps, the y went straight to where the prob lem was and

solved the prob lem as best they could. So, training field person nel is ex tre mel y

important, including drills to insure that training is effective.

Let me mention in closing that I think progress in learning things about

dam safety comes about very slowly. We have failures that occur and im-

mediately after the failures a lot of things are done, but to really obtain solu-

tions to these very difficult problems takes time. After damage to the San

Fernan do Dam in 1971 the State Depart ment of Water Resources instigated

an evaluation program of all dams that were hydraulically filled in the State.

We have comp lete d most o f our analyses of those dams. In 1972 the Federal

Gove rnme nt got involved with inspection of dams and has started a program

in our State and we have complete d the safety assurance und er the federal

program for Long Valley Dam, Stone Canyon Dam and Mulholland Dam. I

think what this is all about is our attempt to reduce the risks to the public.

Reduc tion of risks takes time, yo u have to evaluate what is reasonable, what

is econ omic ally feasible, and as we exami ne ou r past proble ms, we also need

to evaluate in what ways we can improve in the future. I do think it comes

abou t slowly, but it certainly comes about and we need to press on for that

knowledge. Perhaps in another 10 years we can have a conference at Purdue

and we can call it the International Conference on Dam Successes.

{Name not stated):

I got the impression that we knew that there were faults in the found ation.

We knew poo r fo un dat io n c ondit ions existed , as Mr. Leps has said. We also

learned that movements were relatively small, as Mr. Wilson has said, but no-

body seemed to be saying that there was a weakness in the design. The thin

membranes, for example. If they were self healing and could adjust to the

small movements, maybe we would not have had this failure. I was wonder-

ing why that was not mentioned at all in the discussion?

T.M. Leps:

Perhaps I should apologize for n ot having addressed tha t in my oral presen-

tation. It is very thoroughly addressed in the write-up which will be printed


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as part of the Proceedings of this conference . I think perhaps the greatest

weakness in the design of the underdrain system was that it was not flexible.

It was not the kind of a system which could accommodate known stretching

or differential settlements over short distances. The underdrain system was

4-inch diameter ti le, there was abo ut 10,000 ft . of i t , underne ath all of this

clay blanket t hat yo u have heard about. But those tiles themselves were ex-

tremely brittle, easily fractured, and they were resting on a small concrete

sill, or founda tion , so that the u pper half of the tile was exposed and the

lower half was suppo rted solidly in this contin uous concrete cradle which

crossed all of these faults. The drain and its sup por t were bri ttle, rigid, and

any kind of differential movement was going to crack the saddle and im-

media tely crack the tile and in doing so, in cracking and separating, it was

going to tear the asphalt seal which passed underneath the cradle. That

proba bly is where water almost immedi ately got into the underg round start-

ing in year one. To me that is the fatal flaw in the design. It did not provide

an und erdra in system whic h was as flexible and forgiving as the clay blanket

which was set on top of it.

Ho me r Willis, U.S.A.:

We could see, I believe, that the ordinary civil engineer without too much

knowledge of the geotechnical background of this area might not have ap-

preciated the kind of a problem that we have found at Baldwin Hills. In the

past, in many major cases, we have noted that a lot of benefit has been ob-

tained in engaging geotechnical consultants. I wondered if any were on this

particular project or wha t the policy of the agency is now in regard to con-

sultants on major projects.

W. Hoye:

The De par tme nt o f Water and Power, especially with regard to structures

such as dams which are so important to public safety, has always retained

outside consulting help. We have always, in addition, had in-house staff that

was very exp eri enc ed in dam design. At t he time of the Baldwin Hills design

we had a Board of Consultants. I am not sure exactly who the board members

were at that time, but I know that Mr. Marliave was one of the consultants

who came ou t and wor ked with us. Can someone name the others?

R.F. Scott:

At the time when it was decided to empl oy a group of consultants there

were actually three diffe rent boards recomm ende d: there was a first choice,

second choice, and a third choice. To give you some idea of the flavor of it,

the first choice included Dr. Terzaghi. The actual group chosen by DWP was

neither the first, second, nor the third choice, but included Mr. Marliave who

was the geologist. Mr. Van Nor man who was a fo rme r chief engineer of DWP,

a man whose name I think does not have very good c onnot ation s to us now.

He happen ed to be the Assistant Chief Engineer when the Saint Francis Dam

failed in 192 8. He gave his name to t he Van Nor man Reservoir which is re-


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tained by the San Fernando Dam, which failed in 1971. He was on the Board

of Consul tants f or Baldwin Hills. The Board of Consultants actual ly met onl y

three times before const ruction began. From the memos and no tes in DWP

files one do es no t fee l th ey were really very strongly involved in it. That is,

the y were used, Mr. Marliave made a geological repo rt, but there is no t the

indication of a detailed day-to-day, week-to-week, or even mon th- to- mon th

invol vemen t in what was going on.

W. Hoye:

The question also asks about what we were doing then and what we are

doing today. In those years, our Board of Consultants typically consisted of

people that were very well qualified, but th ey did no t wor k 8 hours a day on

our dam design. As I mentioned, we did have in-house people who had spent

decades designing dams an d doing geology. I think in the intervenin g 22 years

we have gone more to outside consultants. Also, the time spent by our con-

sultants in rece nt history has been greater in terms of looking at our dam

designs.

T.M. Leps:

May I insert a very small vignet te? Halfw ay th roug h the life of Baldwin Hill

Reservoir the main designer, Ralph Pr oct or (R.R. Pro ctor ), invited Dr. Terzaghi

to come and take a look at his monument. Dr. Terzaghi was consulting for

my c ompa ny (Souther n California Edison at that t ime) and we found, sur-

prisingly enough, that the only time available to him would be on a Sunday

morning. So Dr. Terzaghi and I met with Proctor and went out to Baldwin

Hills and we were tak en over the who le site and we were sho wn this marvel-

ous reservoir and all the instr ument ation and given a comple te lecture abo ut

the underdrain system, and so forth. When it was all over, Mr. Proctor fixed

his eyes on Dr. Terzaghi and said: "Well, what do y ou think of my prize

reservoir?" Dr. Terzaghi looked d own at the ground and sh ook his head and

said: "No comment "

G.A. Leonards:

Three quick poin ts ab ou t Baldwin Hills. First, as has been described earlier,

leakage from the east toe and fault drains reached 75 gallons per minute on

first partial filling of the reservoir and continued to increase at constant

reservoir level while all oth er drains showed no flow. This means that, at th e

very least, the clay liner was locally damaged solely as a result of reservoir

loading. The reservoir was empti ed quickly. Among othe r observations of

mov em en t was a 3A-inch differ entia l sett leme nt b etwe en the channel inle t

structure and th e gate tower. The difficult y of maintaining an asphalt seal

aroun d the gate towe r and othe r structures is self-evident. Attempts were

made to seal the leaks, but in my opinion the measures could not have been

fully effective. Theref ore, I affirm that seepage into the erodible fou ndat ion

silts in the v icinity of th e gate tow er v ery likely began at first filling of the

reservoir and cont inued thr oug hou t its useful life.


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Second point. The crack width in the drainage inspection chamber,

altho ugh it f luct uat ed, as Stan said, on average increased more or less lin-

early fro m first filling of the reservoir. The rate o f this increase in crack wid th

increased sharply after pressure injections were starte d in the oil field. There-

fore, the measurements clearly show that pressure injections accelerated the

failure of the reservoir, but did no t initiate it.

Third point. Underdrains were installed to monitor the amount and loca-

tion of seepage through the clay liner. The funct ion of the underlying asphalt

membrane was to prevent water collected in the drains from entering the

erodible fou nd at io n soils. In my opinion, t he fata l flaw in the design was not

the brittle underdrains, although th ey certainly aggravated the situation, but

the fact that there was no way to ascertain whether the und erlying asphalt

membrane was intact -- and if the membrane was ruptured, the reservoir

would be lost, sooner or later. A dam should no t be designed so th at its

security is entirely depe nden t upon a single feature whose integrity cannot

be ascertained positively by t he monit orin g system, in time to avert failure.

I believe tha t this is the most imp ort ant lesson to be learned fro m the Baldwin

Hills Reservoir failure.

Juan Muria, Venezuela Oil Co.:

We do have a very serious subsidence problem in the eastern coast of Lake

Maracaibo and we have records going back to 1928. As far as we are con-

cerned subsidence is caused by oil extraction. As I understood from Prof.

Scott, here in the States oil extrac tio n is no t considered a legal cause for sub-

sidence. What is a legal cause for subsidence?

R.F. Scott:

I perhaps should clarify that. By that statement, I meant there has been

no case which has gone to compl etion in the courts in which th e legal testi-

mon y at tribut ed subsidence to oil, water, or gas withdrawal, and then the

judge or jury fou nd t hat tha t was the case, or made it the legal statement. I

did not mean th at people do not accept it, I just mean that I think that many

cases have been settled out of co urt on this issue. In Houst on, Long Beach,

Baldwin Hills, and so on, bu t wit ho ut actually completing a case with a legal

determination.

T.M. Leps:

May I suggest one thing? Jer ry Leonards has pointed out the vital role of

the 1/~-inch asphal t underseal below the drainage. The fac t is, as poin ted o ut

by Mr. Jansen in his presentation, that during the very initial performance of

the reservoir astounding quantities of asphalt came o ut through the under-

drain system. In tryi ng to assess wha t its significance was, I have taken the

crude figures quoted in his paper and tried to relate them to how much area

of the underseal actual ly disappeared thro ugh the drainage system. It is some-

thing in the o rder of 50--10 0 ft. 2 of asphalt underseal tha t was discharged

throug h the drainage system. Now tha t was known at year one, and the


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questi on th at one must ask oneself is how did th e DWP assess tha t loss of

asphalt whe n it was the primary seal against the foun dati on? I do no t know,

I do n ot know that Mr. Hoye knows, but in any event it should have been

the trigger from the very outset that something very serious was wrong. The

question is, what would yo u do ab out it? I do no t have an answer for that now.

Blake(?), Australia:

Question to Prof. Scott. In the observations of the plots of crack width in

the inspection chamber, after 1957 there seems to be evidence of stick slip

mov eme nt in th e plots. Were they ever correlated with the public observation

of the so-called " min or " earthquakes?

R.F. Scott:

No, I do not thin k th at what yo u are seeing is stick slip. Yo u have to

reme mber th at there were many years of observation in a rather small-scale

plot. Observations were made mont hly or bi-month ly of the crack width and

so if yo u expa nd th e scale and loo k at them it does not look quite so much

like a stick slip. Usually, in the winter to spring, there was a steady increase

in the crack width over that period, and then usually in the summer to fall

month s the crack width remaine d more or less stationary, on ly to increase

again the following winter--spring. Mr. Wilson has refer red to tha t as temper a-

ture variations. I have the feeling myself that they might be more interes-

ting than that. It is quit e possible that the actual crust of the earth was having

an effect on the moveme nts too. It is very hard to get those events only from

temperature variations. In any case, they are not stick slip. There is an over-

all trend which, as Jerry Leonards was saying, the rate increased with time

and superimposed on that there are individual jumps, some of which are sea-

sonal that we do no t unders tand. Some of the mov ement s are larger than

others and we do not understan d th at either -- perhaps they were individual

fault movements. We have tried to correlate them with earthquakes as well,

and there are jumps when there are no earthquakes and there are no jumps

when there are earthquakes. There is no correlation between eart hquakes

and t hose individual little jumps.

the baldwin hills reservoir failure 1987 engineering geology v1

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