) ...'''-"'>{'' VENTURA COUNTY FLOOD CONTROL DISTRICT ~ , Tuesday, January 25, 19~9, at 3:50 o'clock P.M. PRE!!ENT. SUPERVISORS. R. E. BARREn'. CHAIRMAN. PRESIDING: EDWARD S. PIERCE. ROB£RT W. LEFEVER, L. A. PRICE ANO RICHARD BARD. L. E. RALLOWELL. CLERK; JAMES W. POOL. DEPUTY '" .. '" ...... '" '" '" '" '"
Fe-100). In the Matter of Matilija 'Dam , (General). Good cause appearing therefor, and upon motion of Supervisor Price, seconded by Supervisor Lefever, and duly carried, it is ordered and directed that the Engineer of the Ventura County Flood Control District be, and he is hereby, authorized and in structed to open the discharge valve at Matilija Dam and to reduce the elevation of the water level in Matilija Reservoir to 1025 feet, the water above that elevation to be . by-passed to flow down stream for the benefit of water users below said dam. It is further ordered that the discharge valve shall be left open, discharging waters which accumulate above said ele vation of 1025 feet, and that said valve shall be closed only for the storage of flood waters.
... '" .. ... '" '" '" '" '" '" RECEIVED COPIES, STATE Of CAlJfORNIA (' ... County 01 Venluro . 1. 1- E. HALLOWEll. County Cl.,~ end ••·oUldo CI.r~ 01 the Boord of .Engineer Supe rvtac... oj tM ventwe Co unrr Flood Control DlJtr!ct. Stele of CoUfoml•• do hereby cet'tify the above 41\0 Icreqctnc to be d true and Correct copy 01 en ex .01strict Attcbrnf3..L--~~_ cer-pl frcm tho minulea of 941d Bo~rd. ol Supetvrscra for the meettnq 01 the d4 10 .I It", t abo v. tndiceted. Zone #l Mgr. ]1<:..4 ( (J .... I/~ (1'./ - IN WITNESS WHEREOF . I hove he teuntc set mv hond end cou••d th. 5••1 01 'old Beard to be offtxod thto.21l.thdoy 01 Ja nua ry . 19-L,,9. File COUNCILf,4I[/
ECWJN L.EE GARCNER U. MAYC HAL V , HAMMON8. JR. KARL L . HELLING I OAH W . ILIFF' CITY of SAJ~ BUENAVENTURA L . H . LARSON ERNl!!:ST .J . PATE VENTURA COl"")JTY--CALIFORNIA CHARLES W. ~E'TIT
P . O . BOX 99 LAWR~NCE E . O LSON CITY MAN"Oe:~ VENTURA, CALIFORNIA H . F . 0"" CITY Al"TORN~Y
GRACE WOODR:UFF :i1 a j' .24 , 1949 --:' ONTROLL~R' CLERK FILE c Board of Supervisors BOARD OF SUPERVISOR~ Ve~tura County Flood Control District ? o. Box 420 MAY 2 5 1949 Ventura, C~lifornia L HALLO~ __ ~_~J?~ G e ~ By -- t.Lemen i Deputy ~-r£i<
Mr. R. H. Jamison h~s cJ~ferred ~ i th the members of the City Council relative to the manner of release of water from the Matilija Dam. during the remainder of' this year . The City desires to continue its cooperation with you, wi~iout relinquishing any of its rights to miter in the Ventura River ,;,:at er shed to which it is entitled. I am instr~cted, theref~re, to advise you that the schedule of release of water from the rh t i l i j a Dam, as pr-oposed by rlir. ,Jamison for the remainder of the year, is consented to, approximately as fol loli's:
1. Until -Iu Ly 1 the release of \lat er wi.Ll, be about equal to the inflow.
2. EarLy in July you '.'fil l release about I.J acre fee~ per day for sLc j ays .
J. From then until Se pt.eziber the release of r;at er ,nil be about e ~ual to the inflow.
4. Early in Septe~ber you ITill release about 30 acre feet per day for from 4t to 6 days.
5. It is estimated that you will then have r emalnlUg in the reservoir above the 1,000 foot level about 160 acre feet, ~hich you wi l l hold in reserve and use during the reillainder of the year to the best of your a bi l i t y in giving so~e relief to the ar eas requiring it. / ". •
Page Two
Board of Supervisors Ventura County Flood Control District ivIay 24, 1949
You will appreciate the City's positi~n that, as stated in ny letter to you of A9ri1 4, 1949, except as specifically consented to, the City will expect its rights to the water from the Ventura River to be respected.
In t~~ing this action we are motivated by a sincere desire to assist the people who are confronted with a serious w~ter shortage t:lis summer ,
Very truly y~urs,
Lawrence E. Olson, City Manager
LEO/mh ':i-' '-;'1Sg · ...... ,~ "T -ly 22, 1949
MEMORANDUM RELEASE OF ~ATER FROM ~~TILIJA RESERVOIR July, 1949 I"~;·:0R;.rIDur,:~: . Robert L. Ryan
The agreement for release of water f'r-o«; Matilija Reservoir this SU~l1er called for a release of about 240 acre feet in July. ~1ater was released for six dayst beginning July 5tt and ending July 11th. The rate of release varied from 18 crs to 30 crs and averaged 23+ crs.
The amount released~s as fo1lows: Inflow to reservoir 23 ac. ft. Release from storage ~ " " Total 277 It It The accounting of the water released, based on spot :neasure- ments, is as follows: Ro. Ojai I"~utual '.'later Co. diversion 50 ac. ft. l8~ ae . l·~atilija diversion 45 n tt 16"1, ~eyer tt l6~'; Percolation above Rd. 44 " I Passing ~eyer Road lJ8 " " ~ 277 n tt 100% A portion of the 44 acre f'eet ;: tha t went into ground wat.er storage above Meyer Road, will be available to the upper users during the next two months and a portion of it will drain out underground to the lower users. The 138 acre feet passing ~eyer Road, on the surface, during the six day perdod all sank within the first two miles below I'leyer rtoad. None of it reached Baldwin Road on the surface. The amount of water stored in the reservoir at the end of the rp.lease period was 314 acre·feet. An effort will be made to hold this amount until September 1st and nUease only that which flows into the reservoir.
RHJ/g1 I -~-1#
COUNTY OF VENTURA STATE OF CALIFORNIA
OFFICE OF COUNTY SURVEYOR COURTHOUSE. iOOM 4 VENTURA. CALIFORNIA March 7, 1950
Honorable Board of Supervisors Ventura County Flood Control District Ventura, California Gentlemen: Herewith is submitted a report as of March 7, 1950 on the opera tion of Matilija Reservoir. In the absence of instructions to theoontrary this office does not intend to store any ,water in I~tilija Dam which is not surplus and belonging to the Flood Control District.- The reason for this is that upon the release of water from the reservoir, it is assumed'to become free water and upper water right users usually take the major portion of the released water although theoretically the water belongs to all of the users down stream. This office intends to release water that is not considered surplus and will do this as long as the river sands are receiving this· water by percolation and none of it will pass Bster Park. At present there is no flow of water past Burnham Road or Santa "'na Boulevard.. It is our intention to let out 5 or 6 second feet of the ,flow and arrive at a release which will satisfy the purpose of perco lation and yet not waste. This matter is offered as an explanation fr~m this office and for discussion as the Board sees fit.
ROBERT L. RYAN Engineer Ventura County RLR/s Flood Control District encl. I , . ,
: .~";""" -,_. c.. -~' _
Metilija Res er-vo i'r &: Ventura River>
March 7, 1950
~arch 7, 19$0
Y.atilija Reservoir Lake elevation 1057.6 - 1394 ac. ft. about 20% full Inflow to lake - 21 ac~ ft. per day. Outlet gate ha~'remained cloged.
March 2, 1950 Plow fro~ North Pork - 4.4 c.f.s. nancho ~atil1ja diverting 3.3 c.f.s. (This is the only diversion) Rancho Matilija returning 1.73 c.r.s. of the 3.3 C.f.2. to the canyon leading to Live )aks area ~herG it Siru(5. Flow at Meyer Road '- 1.0 cof.s. Na llow E.t rurnbs:':1 Rd. nor at 38,ntD. Ana '91vd.
San Antonio Grce:c at High-,'lo.y 1/399 - 1 .. 00 c s f .. s , Plow in Ventura River at mo~th of San Antonio ~reek - 5.47 c.f.s. This 5.47 c.f.s. is rising water at this point and inciudes S~- face flow from San nntonio Greek.
Flow at Ventura City intake - 4.5 c.f.s. City divertinG ~ro~ Ventura River - 4.2 c.f.so City divertins frc~ Coyote Creek - 2.0 c.f.s. Tottil city divcrsio~ - 6.2 c.f.~. - about 4.million C.p.d.
In vi cw 81' t1~t t hac no aurfn.ce flow 13 nov r-eacrring Santa Aria Boulevard, s wat~r should be released end ~n effort nade to put a's much ~der Ground 8.3 poss Lb Le without wus t e pa.~t Ventura City's inte~e. ~enther 'condltlons may chan30, however, and release be d e Laye d , 1'7lliJ'k1U/(]~ There is no 3urface flow fro:n the pool on the apron below the dam. Al l of the wa t e r thrrt origlnate3 ;~d e r the apron is 83capinc down the canyon ,under sr-ound and the Inci.ications are tr.s.t thi:; is a meager amount. The surface of the ~at er in the Docl new ~tands at eleva tion 975. The elev8.tion of the ~ater in tho reservoir i~ 1057.6 or ~pproxi~ately PJ feet a ~ove that in the pool.
If there w ~ s ~ny increased loakage under the dD~ hecause of this eifr er-enc e in e 1 e '/<1 tion, it no doubt would be r-e I'Tec ted in Lncr-e a s e flo'l( f:4'om the pool. No such increase has been observed yet.
R11J/e1 ,) '~llJ 11, 1750
Re3erv~ir ~tora~2. U::.ri:e ::;:evQti cnJ~.ll'r 3, 1 )50 - 1061. 7S 1609 aco !.'to~ Laxe f::l ev t: tLcn ,~r'.11Y 9 J 1950 - 1061. 02 1602 ac . .ft~ •:-l-l... Loss in s tOI'~ g0 durtnz week 7 ac • .:.. l".
G~~atast &~ount stored in reservoir occurred ~ay 11, 195( 1686 ;1 C . ft. tl n .imo un t 3 toped JUly 9" 1950 1602 amY-U1'~ ~31c8.8ed 11 !l 'r a t a I & los t by evaporation 2-cFr ~ot~l amount ~ele2~ed 3ince ~ e r ~ h 8, 1950 901 ac. ft. Amoun t rele2.sod o r- Lo s t r' r-om s t or-age 28!.:,. 11 '] Amou n t of tnflow 9:' :3 2 e d th,:-ouf·;h r cs er-vo Lr- 017;' rr
r~s8rvoir i ~~Ln ~ ~ In.flow to week averaged 1 0 7'3 C 0 i.' S • t)er day ' :I 11 II ~, II (I eutf10'.V frm ;1 1.55 c "f.s o
Vi0 ',; t nru res e r vo i r c . .f os. Fl o w :rc~ North 90r k c.f.s. Total in river ~8 1 ow d.am c.f.s.
:1. o ·:I e t:--or::: ; : ~~H ~ ,l =. ~ :l Gr e GA: .38 cor.s. 2h21con .f' r o~\ ?i<) r' t:1 ~",)rl( c 72 c. f . s , :k ;1 e r from '.rent '"u~ [:' Hiver .. 10 co:f.,s. 3 ~ . ~ ~ ltunl ~: &~~e : : c . from '}e n t ura i'{ ~;. '1 f : r l.07 c.f.so ~ \ l) , ~ :: d.tilija .:. ' .:" ~;-:; Ve n t u r a lliver 018 Cof.s .. L'). • 4:::>';J Col"' .. so
;.":;'0 ';,' at Ve.:lst:,!',,:;. City Inta~ce - JU1:r 1 0~ 1950
SurfaGe flc',i' .i.:1 Coyote Creek < 79 c. r. s , Sur f a c e flow in Ven t u r rr aiver 00
Total surface flo~ available o 79 c. f' • s • A J 1 d i v e r:ted
Ri Cr~Af(D E. Ji\~.IISON Hydraulic Engineer July 14, 1952
Memo to: Robert L. Ryan Subject: Release from Matilija Reservoir
July 9, 1952 Inflow (measured) to reservoir 12.2 cfs. Release to Ojai Valley 4.8 cfs. Release down Ventura River 19.5 cfs. Total release 1 .3 efs. Draft on reservoir (indicated by measurements) = 4.1 cfs. • 8.2 ac.ft. Elev. of lake July a, 1952 • 1124.32 • 6934 ac. ft. Elev. of lake July 9, 1952 = 1124.25 = 6926 ac.ft. Elev. of lake July 10, 1952= 1124.20 =6919 ac. ft. Average draft during July 9, =7.5 ac. ft. This difference in draft on the reservoir indicates that the unmeasured inflow (from springs) is greater than the evaporation. In order to create more storage space in the reservoir it appears advisable to release more water into Ventura River and store it under ground. The release to be made at such a rate that none would waste past Ventura City Intake.
RICHARD H. JAMISmN Hydraulic Engineer COUNTY OF VBl!ITORA DEPAR'l'MENT OP PUBLIC WORKS COURTHOUSE VENTURA, CALIPORBIA January 26, 1959
Board of SUpervisors Ventura County Flood Control District Ventura, California
Subject SUMMARY OJ' OPERATION 01' MATILIJA RESERVOIR
There are forwarded-herewith copies of the "Summary of Operation of Matilija Reservoir" by Ventura County 7100d Control District for the period January 1, 1948 to December 31, 1958, incluaive, for the information and files of the Board and its members.
~~/- x. C. Lorenz Director HPNzhe Attach. · COUNTY OF VDrURA DEPARTMEN'l' OJ' PUBLIC WORXS COlTRTHOUSE VENTURA, CALIPORNIA January 21, 1959
FROMs Engineer-Manager, Ventura County Plood Control District TO: Chief of Water Resources
SUBJECT s SUMMARY or OPERATION OF MA'l'ILIJA RESERVOIR
Transmitted herewith is a report on MSmnmary of Operation ot Matilija Reservoir" by Ventura County Plood Control District for the period January 1, 1948 to December 31, 1958, inclusive.
In accordance with the provisions of an agreement between Ventura County Plood Control District and Ventura River Municipal Water District, operation and maintenance of Matilija Reservoir was taken over by Ventura River Municipal Water District, effective January 1, 1959. .
c. White Engineer-Manager
CWshe
First Endorsement
PROM I Chief of water Resources
TOI Director of Public Works
SUBJECT s SUIOIARY 0'" OPERATION OJ' MATILIJA RESERVOIR
Porwarded herewith is a report on wSUromary of Operation 'of Matilija Reservoir M by Ventura county Plood Control District for the period January 1, 1948 to December 31, 1958, inclusive, for your information and further transmission to the Board of SUpervisors, Ventura County Plood Control District, for their information and files.
l~, \f'vu, ri2tl ~ '- B. P. Needham Chief of Water Resources HPN.he SUMMARY OlP OPERA'fiOK OP MA'l'ILIJA RESERVOIR Ventura coUnty P100dControl D1atrict January 1_ 1948 to December 31_ 1958, Inclusive
1948 - Inflow Wae paeeed through the sluioe gate (elevation 1000") until March 14, 1948_ at which time the gate was closed. Water surface reached the outlet pipe (elevation 1025) on April 2, 1948. Maximum amount stored during the 'year was 351 aore teet at elevation 1029.90. Thi5 amall' ~unt of 8to~age occurred during a par-Lod when the tlow from N'o~th Pork Creek met the needs ot the upper surface diversions. All water was released down Ventura River d~ the 5Ummer months. 1949 - Max1mUm amount stored during this year was 902 acre feet at elevation 1046.68. ~s occurred on April 25. 1949. All watar wa.:s released down Ventura River during the BWmler months. 1950 - Maximum ~~t stored during this year was 1890 acre teet at elevation 1066.68. Thia occurred on May 7, 1950. A total ot 1300 acre teet ot this water was rel••aed down Ventura River. Release was stopped on OCtober 26 1950, at which time water Burrace elevation was l038.2b,J storage equalled 590 acre feet. 1951 - Max~ amount stored was 692 aore teet at elevation 1041.30. which ocourred on March 7. 1951. The pipe line to OJai Spreading ~rounda was completed in the spring month» ot this year. During the period May 8, 1951 to June 16. 1951. Z53 aore teet o~ stored water were Iiivert.ed to spreading grounds. The remainder ot the water was released down Ventura River. Sluice gate elevation waa reached on July 26, 1951. All in flow PlIsaed through the sluice gate with no storage until ~anuary 1952. The inflow reaohed a low ot 0.35 second ~eet during the fall. 1952 - There was no shortage ot water during this year. Rain fall was he&VT and the reservoir filled and overflowed for the t1r5t time sinoe completion on January 15, 1952. Ovartlow continued until June 17, 1952. Sale ot water started dUring this year and water was again diverted to apread1ng. Table No. 8 showa distribution of the water during this year. 1953 - Ths amount in storage on 3anuary I. 1953 was 6960 acre faat. The reservoir again filled and overflowed in January or this year. Overflow stopped in April. Table No. 9 shows distribution ot the Qter. ..~ - .
1954 - '!'he aaount 1n storage on J'anu&17 1, 1951f. ..a 5097 aora teet. '1'he reaenoir tilled anel overt'lowed in Irebrua17 ot tb1a year. Overtlow stopped in June. Table 110. 10 ahowa diatrlbut10n ot the water. 1955 - 'lbe amount in .torage on Janua17 1, 1955' was 5100 acre t ••t. 'l'h8 reservoir did not till this y&ar ~ Max i • 2m storage val 6220 acre teet which ocourred on May 13, 1955. Ho water was spreac1 during th:1s year. Table Ho. 11 ebon distribution ot tbe water. -, ! 1956 - '!'he ..aunt in storage on January 1, 1956 was 4545 acre teet. The re••rvo1r tilled and overflowed during January. OVertlow stopped in June. Table No. 12 shows distribution of the water.
1957 - The amount in storage on January I, 1957 was 4572 acre teet. The reservoir ~il1ed and overflowed during March. OVerflow 8 topped in May. Due to lowered water loveIs in wells down Ventura River, add1tional allocations were mad. to both OJa1 and Ventura River late in the sUl!I:ller ot this year. A 10~ line waa 1nstalled near the pipe line croSling on Ventura River at McCaleb's. An addi tional m acre teet, were released down Ventura River throUgh this line in October to assist in alleviating the ground water shortage in the area. Water users in the Ojal were aJ.lowed additional allocations for irri gation purposes. Heavy rainfall in December added 2078 acre teet in storage during the month. Table No. 13 8bo~ the distribution ot the water. 1958 - The amount in storage on January 1, 1958 was 6616 acre teet. ~ reservoir ~lll.d and overflowed approximately February l~ 1958. Overtlow did not stop until OCtober. Construotion at Robles-Caaitas Diversion Dam, pipe lines eta. in Ventura River below Matil1ja Dam was in progress throughout moat ot the summer. The usual amount ot water was not released down Ventura River during this year, 8ince it would hamper construction operations at the Robles, Diversion. Due to heavy rainfall in the year 1957-58_ water needs 1n this area were taken care ot. storage in the reservoir on December 31, 1958 was 6767 acre teet. Table No. 14 shows the distribution ot water. In accord ance with the provisions ot an agreement between the Ventura County Flood Control District and Ventura River Munic1pal Water District, the maintenance and operation or Matl11ja Reservoir, MatiliJa Dam, Matl11ja Conduit and appurtenant works was taken over by Ventura River Municipal Water District on January 1, 1959. . ' <:: ., .~-
TABLES
Table No. 1 MATILIJA DAM STATISTICS 2 ANNUAL INPLOW AND DISTRIBUTION OP WATER - MATILIJA RESERVOIR 3 ANWAL RAINPALL - SHELDON RANCH NEAR MATILIJ'A DAM - 4 ANNUAL RAINFALL - MATILIJA CREEK ABOVE RESERVOIR
5 MONTHLY EVAPORATION - SOPER RANCH AND MATILIJA CREEK ABOVE RESERVOIR
6 AMOUN'l' OF WATER SPREAD IN OJAI VALLEY FROM MATILIJA PROJECT
7. ANNUAL SALE OF WATER FROM MATILIJA RESERVOIR 8 OPERATION OF' MATILIJA RESERVOIR - 1952 9 OPERATION O~ MATILIJA RESERVOIR - 1953 10 OPERATION OP MATILIJA RESERVOIR - 1954 11 OPERATION OF MATILIJA RESERVOIR - 1955 12 OPERATION OP MATILIJA RESERVOIR - 1956 13 OPERATION OF MATILIJA RESERVOIR - 1957 14 OPERATION OF' MATILIJA RESERVOIR - 1958
PLATES Plate No.
1 HIDROGRAPH OlP WELL SHOWING GROUND WATER ELEVATIONS IN OJAI VALLEY 2 HYDROQRAPH OP WELL SHOWING GROUNDWATER ELEVATIONS IN VENTURA RIVER VAJ..J.£l / . ' ':il";;" " -'...-...-. -,' .. . _. -', -. '_.. - ;- .::"....- . ~....:':-::::...:,;"::::..:.< .-':-." ..: : ~ . _ ~ ': ." :,....,.-,-;::;2-.. - - .'-:: ·~?::;~:·' , '·: : \7""!'~T: ;~;"'':':lf8bfe'·: W2\ _~~ " -..
MATILI~A DAM STATISTICS
1. Date Completed - 1947 . 2. Designed by - Donald R. Warren Company 3. Constructed by - Guy F. Atkinson Company; Bresaie and Bevanda Con8t~ct1on Incorporated and W. E. Kier Construction Company Height ot Dam above streambed - To Crest 198 ft. To lowest epl11way 185 ft. 5. Length along crest - 620 ft. 6. Thickness - At Top 8 ft. At Bottom 50 ft. 7. Elevation above Sea Level - Crest 1138 ft. Lowest Spillway 1125 ft. 8. Conorete Yardage - 51.000 cubic yarde. 9. Reservoir storage at Spillway Leve1- 7018 Acre Peet 10. Reservoir Area at Sp11lway Level- 126.8 Acres 11. Drainage Area of Mat111ja Creek Above Dam - 55 Square Miles 12. Spillway Capacity - 60,000 ers at Water SUrface Elevation 1137 ft. .'
ANNUAL INFLOW AND DISTRIBUTION OF WATER Table No. 2 MATILIJA RESERVOIR ~------_ . _------_._---_.._ ------. . ._ - --_. - - _._-_. ------_ . ------. Amount Release of Inflow From In- Passed Storage ~;_~i~~J _:~~~ _ Ove~ Year flow Down River Down River Sales Spreading flow _. . _. _. ._- .- _ ACRE FT. ACRE FT. ACRE FT. ACRE FT. ACRE FT. ACRE FT. 4CRE; F T. ACRE FT. - · ~: 1949 2,417 All inflow and storage released down Ventura River. ,------.------....------.--- .- - -- .-- .------, --- .- . - ---~ . -. . ------i------~ 1950 3,135 All inflow and storage released down Ventura River• . .. ------.------~ ------._. _. _----_. _ ------1 1951 1,169 253 Remainder of inflow and storage < '------f-- - '-- - - _ .- - -. - . - ---. ._. _. _ _- ' - - .. ~leaaed - <101m 'lentura River --1 i )5.1~a.2-. _ 2~ :?~~34 }17_±_ _.§!~~7 _ 195L 46 L 4-4 5 . .. . 114 _ __. __. 32,610 " ' . , : ~ . 1 9 ~ i ._5,95~ _ e-_ _ 4 ! 5 ~ 6 ~~}.2;t 397 . _~ ~ ~ 8_ _ 552 __. 1 ,_863 2,221 ' '. .. __ ' __ "'_ '. -- · 1 195_~ . _ ..__-.1.171.4: ~, 75.1 ~ __ .__ 1 ~~O.!....- --r - 55? . J4~ ._.__~?? + 3 2 ,464 .~ :~ 1955 _ ~ , ~6 5 2,.535. .; ...... __~, 5.~§ __.. ~2~ _. .N on ~ . 2.7]., ____ ~25 None ;: i · I .1 ~92L _ __l..9.08. _ .._ :;A3.7L__.. ; ~,2Q7 643 . !,)4J: . J.22 t. .?7 2 1 . ( .-!927 §,7!!± .. 1,71"!. __. . ~,~~2___. 26 ANNUAL RAINFALL - SHELDON RANCH NEAR MATILIJA DAM ._Ra i nfa11 Year July 1 to June 30, Inclusive 1947 -48 10.25 inches 1948 - 49 12.49 inohes 1949 - 50 16.54- inches 1950- 51 11.01 inches 1951 - 52 39.63 inches 1952 - 53 13.76 inches 1953 - 54 20.30 inches 1954 - 55 16.81 inches 1955 - 56 24.53 inches 1956 - 57 18.44 inches 1957 - 58 46.11 inches 56 year average for above station : 24.70 inches ANNUAL RAINFALL MATILIJA CREEK ABOVE RESERVOIR A raintal1 station was established and put into operation ~ediately above MatillJa Reservoir in December, 1951. Annual totals at this station follow: 1951 - 52 51.08 inches (Partial Estimate) 1952 - 53 16.99 inche. 1953 - 54 24.3:5 inches 1954 - 55 22.10 inches 1955 - 56 '2:7.48 inohes 1956 - 57 23.63 inches 1957 - 58 59.79 inches 7-yesr average for above station =32.20 inches ~e rainfall 3tatlon immediately above Matilija Reservoir has only been in operation tor a period. ot 7 years; however, by comparison. this area seems to reoeive approximately 25~ greater rain tall than that at Sheldon's Ranch, which 1s located approximately one mile below the Re5ervolr. . ' ..~ . .. "- 1952 j Monthly SOPER RANCR ABOVE MAfILIJA Coett. RESERVOIR " - .. . Month state Lat. 31+- - 28 . 83 j Lat. 34*-29.63' Bulletin Long. 119·-1taa~1 Long. 119--19.68 1 '. No. 54- Pan Pan take Tab1e-IO Evap. Evap. Evap.' Evap. Jan. 0.96 Peb. .77 Mar. .92 Apr. .87 .363 .316 .352 . .306 May ·90 .483 .4-35 .556 .500 Jun. .99 .468 .4-63 .501 :gg~ Jul. .95 .612 .581 .703 Aug. 1.02 .672 .685 .767 .783 Sep. 1.10 .621 .683 .663 .729 Oct. 1.12 .373 .418 .428 .4~9 Nov. 1.12 .295 .330 .234- .2 2 Dec. 1.03 .200 .206 .18l+ .190 TOTAL 0.98 1953 J"an . 0.96 .216 .207 .162 .156 -.I Feb. .77 .380 .293 .324- .2!+9 Mar. .92 .351 .323 .349 .321 Apr. .87 -. 351 .305 .l+02 .350 May .90 .510 .459 .561 .505 Jun. .99 ·501 .496 .566 .560 Jul. .95 .711 .675 .825 .784- Aug. 1.02 .635 .648 .743 .758 Sep. 1.10 .552 .607 .616 .678 Oct. 1.12 .533 .597 .512 .573 Nov. 1.12 .348 .3§O .305 .342 Dec. 1.03 .370 .:5 1 .295 .304- TOTAL 0.98 5. 458 5.381 5.660 5.580 195!+ Jan. 0.96 .260 .250 .190 .182 Feb. .77 .386 .297 .262 .202 Mar. .92 .257 .236 .232 .213 Apr. .87 .317 .276 .361 .314 May .90 .336 .302 .441 .397 Jun. .99 .440 .436 .573 .567 Jul. .9'5 .525 .56§ .747 .~10 Aug. 1.02 .507 .57 .667 . 80 Sep. 1.10 57 .513 .639 ·703 Oet. 1.12· .a 12 .461 .45~ .512 ( ,l Nov. 1.12 .320 .358 .20 .300 Dec. 1.03 .222 .229 .1]2 .117 TOTAL 0.98 4.669 4.601 5.009 4.957 ,...... r" ...., j Monthly 80m RANCH ABOVE MATlin Coer!. RESBRVOIR Month state Lat. 34w-28.83 J Lat. )4w.29.6§' Bulletin Long. I Long.' .'" , ". 119°.-17.56 119°.1la6-' ·it No. 54- Pan take Pan lei e Table-IO Evap. Eva;. Evap. Evap. - . j ' Jan. 0.96 .163 .15 .090 .086 . ~ -~ ":"~ Feb. .?7 • 24-1 .186 .200 .1~4 Mar. .§2 .310 .285 .308 .2 3 .r Apr. · 7 .460 .4{)O .460 .400 May .90 .33~ .305 .4-0~ .368 Jun. .99 .1+2 .4-20 .51 . .513 Jul. .95 .;65 .537 .072 .638 Aug. 1.02 .b,b .549 .150 .765 Sep. 1.10 .590 .649 .652 .711 Oct. 1.12 .358 .401 .4-03 .451 Nov. 1.12 .209 .301 .245 .274- Dec. : 1.03 .135 .140 .106 .109 TOTAL 0.98 / 4..491 4,429 . 4.813 4-.758 1956 :Tan·. 0.95 .134 .12~ .116 .111 Feb • .161 .12 16 .127 ../ ·77 . a \" / ~ Mar. .§2 .353 .325 .39 .362 Apr. · 7 .222 .296 .258 May .90 ':-~~a .256 .373 .336 Jun. .99 . .1+41 .437 .546 .541 Jul. .95 .5a1 .523 .665 .632 Aug. 1.02 .5 0 .551 .619 .631 Sep. 1.10 .536 .590 .620 .682 Oct. 1.12 .336 .376 .362 .4-05 Nov. 1.12 .4-4J+ .365 .409 ; .497 Dee. ; 11'03 .343 .353 .273 .281 TOTAL 0.98 4.'78 4.383 4.794 4.TI5 J\ r 1957 Jan. 0.96 .166 .159 .124 .lla Feb. .17 .102 .079 .08; .06 Mar. .~2 .279 .257 .356 .328 Apr. · 7 .~90 .252 .35~ .311 May ·90 .338 .30~ .40 .367 Jun. .99 .530 .52~ .611 .b05 Jul. .95 .610 .63 .74-7 .710 Aug. 1.02 .6 4 .629 .7~2 .14-7 Sep. 1.10 .47 .521 .5 7 • te2 • ... . Oct. 1.12 .285 ·'~4 .298 .334 (-) Nov. 1.12 .227 . .25 .210 .23~ Deo. 1.03 .220 .2'1 .15' ,15 - TOTAL :b~a It,198 If 162 *,626 l+. .580 ! - ~ 'hi \.-.1 , ,,< ' Ail10UNT OF WATER SPREAD IN OJAI VALIF.Y T;:tble No. 6 FfiOM MATILIJA PROJECT ~ _ ~ : ! ; ~' i. I: Acre-Feet : Month 1950-51 1951-52 1952-53 1953-54 1954-55 1955-56 1956~57 Oct. 0 0 322 0 0 0 0 Nov. 0 0 300 0 a 0 a Dec. 0 0 296 66 0 0 a J2m. 0 77 155 0 0 41 o ,; . Feb. a 268 209 113 a 276 0 Mar. a 257 311 ' 266 0 221 236 Apr. 0 274 235 288 a 237 180 . 'I ' • May. 0 293 123 255 a 270 63 ::: ", : ... ~ Jun. 253 240 0 18 0 189 Q " Jul. 0 301 0 0 0 95 Aug. 0 324 a 0 0 0 Sep. 0 282 0 0 0 0 Annual Total 253 ' 2316 1951 1006 0 1329 Accumulated Total 253 2569 4520 5526 5526 6855 r-.J I ·, r;(. '"\ AMOUNT OF WATER SPREAD IN OJAr VALIBY Table No. Q F~OM MAT ILIJ A PROJECT I ~ ' , .; ~~: " ., , Aore-Peet H : Month 1951-58 1958-59 1959-60 1960-61 1961-62 1962-63 196,-64', . .'.; ..?.' . Oot. 2,6 . . ~ !~ a ' , ~ , , ~! Nov. a 185 Dec. 0 218 Jan. I 260 Operation t~en over by Ventura ver Feb. 247 Munioipal Wa er Diat. Effeotive 3. • 1, 1959. Mar. 27° Apr. 168 May 64 Jun. 21~ Jul. 104 Aug. 88 Sap. 196 Annual Total 1611 639 - Aooumulated Total 8945 9584 ; . . ANNUAL SALE 01' WATER !PROM MATILIJA RESERVOIR Amount or Unit Water Sold Price 'lota1 Year Aore Feet Aore Poot . Amount 1952 38.32 $ 10.00 $ 383.20 1953 397.24- 10.00 3 1 972. 4-0 1954- 552.12 25.00 13_803.. 00 1955 498.47 25.00 12,461.75 1956 643.23 25.00 161 080.75 1957 560.16 25.00 14-,004.00 1958 396.87 25.00 a 10,205.95 Grand Totals 3,086041 $ 70 1911.05. a Includes 947,400 gallons eold to Halller-ca~e Con.truction Company @ 15 cent. per 500 gallons. .'r'\. - r Operation of Matl11ja ~esorv01r - 1952 Acrv Fc.:et Re OE;rVO~ .r First of f:!OlltL l\m't. 01' Released from R86Grvolr Chont:;e Am't.1n .. r10nth InflolrJ inflow in StoraGe ~ vJat(~r S. f.m't.:Ln pass<.:u Down To Ojal Evapo Storage ; and of E'Iev . Stol'a~c down river River V::.tlley ration Total Month : ,:} i 1 2 4 6 7 8 g 10 > ' ' l ~' Jan 1012.34 103 1'7,870 o 77 7000 ' i'o ~' 896 "; 2 :-~ ...~~ . Pcb 1125.25 7000 2,700 o 268 7000 ° , Yr, J ' ~ . I'lar 1125.05 '7000 12,370 12 113 o 257 257 ° 7000 12.11 ' . Apr l~ , 650 4-, y(6 o 274 o '7000 4,31 ' · ~~ l . 2,130 1,B3'( o 293 o 7000 1,83: , ~J.un 1,260 956 o 304 o ?OOO 95';, , ':1. Jul 1124-.76 '1000 o 301 379 -75 6925 .'.. () .. -., . : ," ... . Au :; 1.,10(3· 852 o 92 4-16 -160 6765 ; : Sop 8S -519 624-6 ::e. . ::..,.. .. Oct 1118.65 o 52 374 -306 Nov 224 o o 6;,60 .. .~ u 'rotal 3272 He s vr' f'a c c flmJ ,:'c Sl~ r.t::; At"I;} Bc u Lc var-u J Im. 22, 1952 Jr-tll Nov, ] ~152· a ;:: ' Lnc Ludc s 20 ac . f't. Geld ani 1'3l:d i ll Uppc r- Verrt ura River Valh:y, : ,', .' ~ .~;' ., . : :'f· '~1l" .~''lM.;i : .:.: ~: /.» ...... '1:- .W·...... , 0 ~ ~::. ~ .: ~: ; . :" " ,. r. t ~ , , ' .... '\ " " . " , "- . . ~ . t~ ;'it' .~ . ~, . . ' . ."!f:. ;.~~:: : . ~ . :: ~ ; /~ V .).; . oper-a t j on of ~ l\1attlJJa Reaervolr - 1953 Table Jfo g .:.;;. ".;';;;...... ' ; ...... ~ 7 ;.-'- • •: ,' : . ' ~ ~ ..: ~'tl ,:\' ... : . · ·' ~· I · Acri;; Feet ".: \ .~ ;- ' . R~Ber\'o1r Alil'~ , 1 of Change Al1l t . in ,.. F;l.rst of 14o:1th inflow lk Leaaed i'rom n~13t;rvolr tn Storbb~ £t' f·1onth : Ir~rloiJ Qvef. "" pa e ae o 1-i);-~i1 BtoraS';; end of fl~Y water S AIrl't.1n down r.~ 'vt:r 1'.i'O OJul!l!:Vapo- ; Month . i" j f,. ~ ~: ~e t cr-as e Valley ;,: E1E:v. v e- River ration 'rot al ;'I 1 2 3 4- 6 .'( 8 q 1 1J ll '?~ , . , 5 ;.'. " : ~~ Jan 1124 ')) 6q60 16qo 1491 ..- --_.Q_-,..._J.5 2-7"" __L- __159.. _ ~ . _.-!:~.;;'~ __I.QOO 1:.1?1IT" ::'7?! Feb ~.l!l. 6" 1124-.92 7000 f.)50 -.107 0 209 _ 2!±.L..- f--. 7000 . •37; . . .: ~. · r~ ! , _nJ. __ ° ~(,;6t· Mar 1124.87 7000 7.5l?:-. 4-46_ o... 35 .. 346 _ I-__ ._.JL. .-1Q.OO , - .: _;? ~ . Apr I 7~ 2~ __ .f-2__._ 1- .. _ or:~~" i • l12 t . 8') __4:2.L .. f--- .. _-Q_ .- f--~Q:]- ___BQ..__...':-_:-.32__ .929.8__ .) . ,: ~ .. ,.\.~ , .. " May ~ 2Q~ . ., . 0; ;. 1124.')9 6968 I 4-J,L 280 0 142 ~.5.L .._ __ __ ~ ._ --63_ .. Q9.Q5- , v : , ..-:. ~ I " ; " ' ~ f ~ : Jun , 3l~7 _j!±1~ __22 .. ·0\;1. 1124.08 690') ...28 .w 1-....Q5._-- --11') -lIS 67QO ;:~ Jlll 112~ 1') 67QO ! _~9 8I.~_ Q.~- '0' , 244 244- f-.. ...5.53. .__ .... _____ ._ .. ..__ ___ .-6$.2. ._ 6101 ~, ' . -----_. >--_._----- , .. Aug 1117 40 6101 ! 184- 184- -2~ __ __7.5.. 78 ~--s8 ! -')38 _ ~55.-tU iii;' ,f .- Sep ·1 d ~ 1112 ., 8 ')')6"3 14-3 143 .12':1-_ -.:LI 68 .-'79 I! -21.9...... ')284 . I d~; Oct \l-_~2rL ~ 22Q __ i . 1110.00 .2£~ __.151___ __ 9:1_._1----. .. __Ql.. _ _ 1- .-=-~.f:9. _ .1- .5.055 -7:1,.. -- .', ' Nov · 11107 . 7 4- ')055 287 1--__1.2,2 0...... _-_.__2'6._- _.___.9..._....1--...3£.._...... _-till. ')171 O( -- ~ ! I .,' Dec 1108.89 ')171 242. .. 1]7 _._- _9.'_ ·-Tti'L~"",.d5~ " ~ = J~ - <-.:.-7it~':'=~!!~I~ ~ '. - _- ._- .. ,... .: ~otBl 6 .9~ · 22~ 5954••.- .=.:I__ 452 '::::r-1191~ 5 5 .::... ,;,_-=:-:..:555,;,~::--:. :. '-=- : 3261.:.-:~ ~~ :"!"' .--!::::.; :...:::=..~~ .. -- ...... -::.:::..:....=....:..___ ==::-_":"". .:..:=. ..-_-:....::..-- c- ' . - = - , t""" Note: No water passing Santa Ana Blvd. since r,iarch 27, 1953. ' I. ' ). '; ' 11 II II Vt:ntura City Intalce since i'la r ch 27, 1953 " .~;!,.' (a) ~11d ..' Includeg 52 acre f8et nnd used in upper- Vuntura River Valley. I · ..\ i; I . , :,..., f" • .~ ~/f} .' , ; :e..~'- ~ ~ • • . .- :-'.. ~ '_ " '\lI! ' " ~, . ,~ , ~~- :~- , " " , ' : - " ' ': \'~ .' , ' i; • ,f ~ ...... n ,:'~ Opoi-» t t o n 0':: Ma ci i i j H Rc SCI' vo l r - 1~5L~ Table Ho. 10 ' i;fi ' ", : ~;r ~ J' I Acre FCE;t { , t . : ~ . ; Reservoir Am ito of Chun~c Amftotn . ;;,~ First of" f·.io:1 th i c r Io !! HeJ.ot.s8d fram He~ervolr in S tor-a r:e Over~ hbnt~ EnI Lo w pnsscd StorLl C0. end of flo.:!' . : ~ :,f,fffl i \Vater S A! "ll to in down river De:v.n To Cjnl E"'3pO- , Mor.th :, : ;~. E1ev o Storace RivtJr Valley PDtion Total : '~~ r)1 'j1 1 2 J h ;: 6 7 0 9 10 ] 1 ;. ' ~ ~ J 8,1 110EL16 S097 q61 2'r; 0 2 +1L2 + Lo + 7S6 rOe) 1 - ri'.M\.~ :'f~ff: Feb 1115034, 5863 1600 J73 0 114 +2L~ ~ 90 +1137 7000 21.Cii'!' . ,~~ IAor 112)10[;6 7000 1600 1161 0 2GC) +1;:' -?17 0 7000 Oh);'~ '" . ~ , Apr 112Llo(n 7000 1462 1132 0 2q8 - '32 -330 0 7000 I017:,i May 11211 087 7000 6115 313 0 288 -Lh -332 0 7000 2L"I - , .. • ~...i O . ~ ~ Jun 112L ofl2 7000 345 333 0 120 -63 -IS3 - 171 6629 , t }lrl, .'... J,ll 11230L7 6829 240 21 •.0 h92 100 -77 -669 - Ij69 61 ,)0 .o'~ 'i , ~ i ~ . Au~ 1117091 GIGO 181 1,Sl )24 81 --75 -650 - 600 5hAo O;'ij , ., ' \ Sop 1111082 5~80 117 117 101 91 -69 -261 - 261 5~F) 0, " ; ~ :- ", . Oc t 1109036 5219 112 ]12 . h~ A2 -t:;O -107 - 107 t:;O?? 0 : ;~ Nov 110704.2 5022 165 165 19 37 -16 - 72 - 72 !JqC;O Om , "." ~ ~ .> ~ Dec 1106071 4950 346 189 0 10' + J - 7 + 150 ~100 ,;.~;a . -,'J Totol 7774 L753 1201 1492 -325 - ~l"i ..J.3 246 .. · . 'i ·e...., 0 ·"" Note: Cohoon include3 amount in Column 11. , , ~~ 4- . ,'-.. Plus signs in Co l.umn indicates pr-ec Lp l t a t.Lon exceeds OVnCOi',9 t.Lon , .' 7 r Amount spread in Ojl1i Val1e~T, Fehrunry to i.lay, inclusive ., 9L,0 Acre F'ee t , , ·.,f . ~ : ".. "- Lowest elevation of Reservoir g 1106068 rn ~947 Acre Fee t , 12:00 M Dccemh8r 3 0 .J ,; ~ " . .; f \ " h-'.~ , , .~ Operation of Matil1ja Reservoir - 1955 Reservoir First of Month Am't. or Released from Reservo~ Month Inflow Inflow Water S Am't.1a Passed Down To Oja Evapo- Total Elev. Storage Down River River Valley ration 8 .>: 88 o -12 "' \ 4046 55 +47 2 1 _~ote% Column ~ includes amount in Column 11. Plu8 sign in Column 1 indicates precipitation exceeds evaporation. :-. ,{ ( I '!'able 110. U OPERATICN OF MATILIJA RESERVOIR - 19.2§. RESERVOIR AMOUNr of RELEASED FROM RESERVOIR i AMOUNT In FIRST OF MONTH INFLOW ACRE FEET ICHANGE STORAGE PASSED MONTH INFLOW IN ENOof WATER S. AM'r IN DOWN QOWN TO OolM EVAPIlH - I . VALl£Y TOTAL ISTORAGE ELEV. SrOIlAGE RIVER RIVER ATION MONTH I JAN. 6 11-1 FEB. o 6 1 MAR. APR. 0 MAY . JUN. 48 61 . .-i " •'J ··'JUL . 260 260 1 1 - 6401 o ,:J AUG. 1 16 111 6 SEP. 1 1 OCr. NOV. 110 DEC. ~ __ .. 26.- 2l .. .'. ,,, . :~ ,'. \ . Ilfab1.e \ . ~ : 110. l' ~ !. ~ ;·!If. i :~ ')& O'pERATICN OF MATILIJA RESERVOIR - 19s:l- ' , jJ, . ~ ~ .---~------~---:"""""'r------r------n-----.-----~-....------~ " R£S£I?VOIR AMOUNr of RELEASED FROM RESERVOIR I AMOUNT In FIRST OF MONTH INFLOW ACRE FEET ICHANGE STORAGE ' PASSED MONTH INFLOW END of WArER S. AM'r IN DOWN TO 0.1041 E VAPIJII. I IN DOWN TOTAL EL£V, STORAGE RIVER VALLEY A riO/( ISTORAGE MONTH RIVER I o FEB. o MAR. 40 APR. o + 4 MAY JUN. JUL . 12 42 101 - AUG. 1 0 l~ - SF? 66 OCT. 6 - ·n - 684L 66 NOV. o 18 - 401- DEC. Q_. Q. 6 14 1 1 .~ -'f: ,/ .. ' t I ·1" . •: J, .r, :;-j.. 0 ;.'. OPERATICN ' ~ 1 1f OF MATILIJA RESEIfVOIR - /9£H. ' " hble .0. 14 -, " · 1 " i ,! RESERVOIR AMOUNr of RELE4SED FROM RESERVOIR AMOUNT in I ~ f INFLOW ,j' nssr OF MONrH ACRE FEET IICHANGE STORAGE ~ f OVER- MONTH INFLOW PASSED IN '. DOWN ro I END of WAreR s AM'r IN Oo/AI E VAPtJIt- .» DOWN TorAL . FLOW etev, RIVEN VAL l EY A TION ;STORAGE MONTH SrONAGe RIVER 0 ~i :.I ~. ".ti JAN. :~ ~i: ; 0 1 FEB. ; . ~ ~ : MAR. 11+ ,~ '--" - _ APR. 125.18 0 MAY 0 JUN. 0 0 JUL. 1 0 0 AUG. S£P OCT. NOV. DEC. ~,~ . ~!~5 ,__ ,sS..__ _ -- 0-. - -. _ . ~- ---'Q ..- .. _ ~ .~ - --- _ _.et« 68.111 65.040 150 2646 124 2 20 + !5~ _ - ' - - ' - -- - - . ------,- . - ." '. • •. • BECHTEL CORPORATION ~ ~ ENGI~EERS"!CONSTRUCTORS TWO TWENTY BUS H STREET •••• SAN rRA~CISCO,CAL.I FORNIA MAILINO ADDRESS A 0.80)( :agOI ..... rMHCI.CO,CA~rO"NI.e~ue April 10, 1965 Mr. M. C. Lorenz, Director Department of Public Works County of Ventura. " , Courthouse Ventura, California.' Subject: . Review of Matilija Dam Dear Mr. Lorenz: Reference is made to your letter of April I, 1965, subject as above, with which you enclosed a copy of the IIStatement of the' Ventura County Board of Supervisors Regarding Matilija Dam II, and requested Bechtel Corporation to submit a statement in compliance with Conclusion No. 3 of. the Statement, In Conclusion No. 3 it is requested that IIBechtel Engineering in consultation with the State Department of Water Resources and the County Department of Public Works, prepare and file with the Board a statement that the Matilija Dam can continue to be used with assured safety if certain enumerated conditions are met." IIFor each condi~ion there must be a clear definition of the requirements and the estimated cost of achieving these requirements. ~. In the Bechtel Corporation Report, '!Review of MatUija Dam, February 1965", two major matters affecting the safety of the dam were fully discussed: (ll the condition of the concrete, particularly in·the . upper part of the dam; and (2) the stability of the abutments. Alt~ough a.ctually indeterminant, the general order of magnitude of the safety factor with respect to failure of the concrete under va.rious conditions of loading can be estimated. However, th~ condition of the a.butments is unknown and will rema.in 80 until the relationships between abutment deformation and reservoir water loadings can be est~blished by means . of installed, instrumentation. '. a(}t~ £~.:e- «H.'" • v Mr. M. C. Lorenz - ~ - April 10, 1965 The present outlet capacity or any feasible modification of that capacity would be insufficient to avoid uncontrolled water loading of the structure resulting from a. hea.vy storm. Even if the reservo;r were drained completely and the outlets left open it could fill and spill during a storm. The engineering studies cited in the report indicate that the stability of. the structure would be doubtful when subjected to moderately strong earthquake shock at full pool. Since both stability conditions . depend upon natural and unpredictable" phenomena. the risk involved cannot be evaluated. .. In view of the situation outlined in the foregoing paragraphs it is obviously impossible to absolutely ~Iassure ~I or ~Iguara.ntee~r adequate safety of the dam under any conditions short of complete removal of the structure. However, it is our considered opinion that the risk of failure of the dam would be minified when the reservoir level is held below Elevation 1075. The existing outlet capacity should be increased as a precautionary measure, and careful observations and measurements made during this period. This opinion does not include any attempted .' .. evaluation of storm risk but earthquake occurrence with an intensity of VI to VII (Modified Mercalli Scale], or less, has been considered. It may be noted that climatological records indicate that the occurrence of a severe storm during the summer and early ,fall months would be . most unlikely. . " 'Lowering the spillway crest as suggested in the report would certainly increase the safety factor of the dam materially but in the light of our present knowledge of the abutment conditions, could hot be con sidered to remove all risk, particularly during the winter a.nd spring storm season. Some unknown degree of risk would also 'exist during a partial filling of the reservoir for test purposes, but if carefully controlled and closely supervised, the risk would admittedly be less than that during a natural seasonal cycling of the reservoir level. In summary, it is our opinion at this time that the risk of failure ot the (iam or of catastrophic damage therefrom throughout the dryer summer and fall months would be very small if (1) the reservoir level is k.ept at or below Elevation 1075; (~) additional outlet capacity is provided .. ., ", . Mr~ M. C. Lorenz - 3 - April· 10, 1965 as a precautionary measure, by the installation of a 36 inch blow-off valve on the existing 36 inch conveyance line; and (3) meticulous surveil lance, readings of a.butment meter8, and periodic marker pla.te su.rveys are conducted throughout this period, and a procedure established for prompt evaluation of the data and implementing any necessary action. The cost of the valve installation is estimated to be about $2.0, 000, including the cost of the valve• . Lowering the spillway crest to Elevation 1105 would substantially increase the safety of the dam during the winter and spring runoff periods but on the basis of pre sently available data it is not known whether this modification is actually 'needed, or if accomplished, whether the improve ment in safety would be sufficient to permit the dam to be considered ~'safe II with respect to all reasonably anticipated hazards. This modifica. tion would cost about" $400,000. Regardless of whether or not the .modifications are made it is considered imperative that the careful observations, meter readings .and surveys be continued during this period on an even more rigornus basis than during the summer and fall. Reference is also made to a memorandum frnm Mr. J. D. Walters dated April 1, 1965 in which he requests that the scope of the cost and time estimates of Item' (Z) of your letter be extended to incl.ude several other ite.ms as discussed below. Owing to the ve'ty limited time available for making these estimates, they must be recognized only as approximate ~'orde.r··<)f magnitude~'estimates. "Estimate of cost of Bechtel Corporation&s s~l.':vices . during test period from May through September i 965. ~' These services would include. analyses of meter data, . field inspections, consultant services, structural analyses if required, and reporting of findings. The estimated ccat : is $10,000. , (2). .: . "Estimate of cost for additional core and soniscope testing "~f the concrete. II This item would include all subcontract ~ork, Bechtel s~pervision, analyses of data, and reporting of findings. The estimated c:ost is $20,000, and would require about six w"eeks to accomplish the work. Mr.. M·. C. Lorenz '. 4 - April 10, 1965 " , (3) ,"Estimate of cost and time to comple.tely remove the dam... The cost of removing the dam to Elevation 980, approxi mately the original strea.m bed level, would be $350, 000, and would require about 9 months time. ~his estimate is based on the use of explosives to break the concrete, and disposal of the materials in the immediate vicinity of the dam. However, in, view of the silt 'accumulations presently in the reservoir area, removal of the dam only to Eleva- . . tion 1000 might ·be considered. This would cost about $300,,000 and would require about 8 months time. (4) "Estimate of cost and time to remove the upper 5 tiers of concrete in the 8 center spillway bays of the dam. This estimate should include necessary modification of the walkway bridge structure across the dam. ~' As noted above, the estimated cost of the work is $400, 000 based upon use of hydraulic rock jacks to break concrete, and a crane and barges operating in the reservoir at pool Elevation 1070. Mater';als would be disposed of below minimum pool level. The walkway bridge would be replaced by a steel structure. A new concrete spillway' crest structure would be placed to Elevation 1105. The time requir,ad to-do the construction work would be about 5 months. " · (5» ~'Estimate of cost and time to rern..ove and replace the " , concrete under (4) aboves " The same procedlire~ would be followed as in (4)'above except that new concrete would be placed to the same elevations and configuration as in the existing dam. The estimated cost is about $600, 000, and would require approximately 8 months to do the work. , ., , .. . ' .. ", I ' ... ,a w~ Mr. M. C. Lorenz . AprU 10, 1965 - 5 - . "le trust the information furnished herein will satisfy your immediate requirements. Yours very truly, -Ft/.~r~ KVT:ml . Karl V. Taylor" . ,- .. Assistant Manag'e"r, Hydr,? Engineering cc: Robert B. Jansen Supervisor, Safety of Dams . State Department of Water ~esource8 ._.,. .. ' ... :I I, .. I " ...... , , , . I ... . ~1__I.:>~ I COUNTY OF VENTURA ;:2.p..!:!- DEPARTMENT OF PUBLIC WDRKS COURTHOUSE VENTURA, CALIFORNIA .IOOt OFFICE OF THE DIRECTOR TaL&PHONIl 848·808' April 20, 1965 Board of Supervisors Ventura County Flood Control District Subject MATILIJA DAM - ECONOMIC STUDY Gentlemen: The attached Economic Study has been prepared as directed by the Board of Supervisors on March 31, 1965. The conclusions of the study are shown on Table 2 (Pag~ 8) which indicate a benefit-to-cost ratio equal to or exceeding 1.00 only for two situations, both amortized over a 20 year period (assuming a 20 year life for the repaired structure) and using a water value o~ $60 at Matilija. For water valued at $30 per acre foot at Casitas or $40 at Matilija, which were the values used by V.R.M.W.D., further testing and repair of the dam cannot be justified on an economic basis. There is justification for the consideration of a $60 value for water as this is the approximate price anticipated for Feather River water when it is delivered to the County. There is no desire on my part to argue the value of water. The two rates used were done so for the benefit of the Board of Super visors to see the effect of $60 water versus $40 water in justifying any decision regarding Matilija. It should be pointed out that the assumptions used in this study have all been made on a conservative (i.e., high cost) basis. Thus, the insurance costs have been estimated at $100,000· per year. They could very easily be considerably less than this figure. Recreational benefits have been over looked completely. Certainly there are some recreational benefits because of the presence of Matilija Lake. Estimated costs of repairs have necessarily been estimated on the high side. Correction of all these factors would probably increase the benefit~to-cost r~tio and thereby increase ~e justification for the rehabilitation of Mati1ija Dam. Board of Supervisors -2- April 20, 1965 The computations of the various alternative courses of action, which are detailed on pages 2 through 5 of the report, are summarized in the table appended to this letter for ease of reading. Because the results of the Economic Study are marginal at best and depend upon safe abutment conditions and a probable 20 year life, I find it difficult to recommend continued testing and engineering study of the problem. ~though the total costs will not be changed by transferring ownership of the dam, certainly the acceptance of t~e ownership and corresponding responsibilities of ownership by V.RoM.W.D. would simplify the decision which your Board must m~ke. Hence, my recommendation is that immediate negotiations be conducted with the V.R.M.W.D. to provide for that organization to accept ownership of the dam, responsibility for paying off the outstanding bonded indebtedness and operating expenses of the dam, and a joint participation of studies and repairs which are necessary. Sincerely yours, ~~ M. C. Lorenz Director MCL:np Attachments SUMMARY OF ANNUAL COSTS (Based on amortization over 10 and 20 years) Amortization over Item (Total Cost) 10 Years 20 Years Alternate 1 1) Immediate Removal of Dam ($350,000) $ 43,300 $ 25,700 2) Amortiz. of Matilija Bonds ($1,400,000 +Int.) 149,500 79,500 Total Annual Costs if Dam is removed now: $192,800 $105,200 ------Alternate 2 - To perform further testing and then remove the dam. 1) Test Items - Pump water into reservoir $ 70,000 Increase outlet capacity 20,000 Consultant services 30,000 Flood Control Dist. costs 10,000 Liability insurance during 50,000 test Total Testing Costs: $180,000 $ 22,000 $ 13,200 2) Removal of Dam $350,000 43,300 25, 700 3) Amortiz.of Matilija Bonds ($1,400,000 + Int.) 149,500 79,500 Total Annual Cost of this Alternative: $214,800 $118,400 ------~ Alternate 3 - To perform further tests, remove upper 5 tiers of concrete in spillway and remove dam at end of 10 or 20 years. 1) Tests (as above in Alt.2) $180,000 $ 22,000 $ 13,200 2) Remove 5 tiers of concrete 400,000 49,500 29,500 3) Removal of Dam after 10/20 yrs. 350,000 +esca1. 41,000 23,500 (sinking fund) 4) VRMWD annual operational costs 5,000 5,000 5) Liability insurance, Annual cost est. at 100,000 100,000 6) Amortiz. of Matilija Bonds ($1,400,000 + Int.)· 149,500 79,500 Total Annual Cost of this Alternative: $367,000 $250,700 Alternate 4 - To perform further tests, remove and replace upper 5 tiers of concrete in spillway and remove dam at end of 10 or 20 years. 1) All the costs of Alternate 3 $367,000 $250,700 2) Replacement of 5 tiers of concrete ($200,000) 24,700 14,700 Total Annual Cost of this Alternative: $391,700 $265,400 SUMMARY OF ANNUAL BENEFITS *Under Alt.3, total annual benefits estimated at $156,070 (by VRMWD) *Under Alt.4, total annual benefits estimated at $205,200 (by VRMWD) **Under Alt.3, total annual benefits estimated at $251,390 (by M.C.L.) **Under Alt.4, total annual benefits estimated at $328,520 (by M.C.L.) *Based on $30 per acre foot for diverted water (at Casitas) and $40 per acre foot for direct use water (at Matilija). **Based on $50 per acre foot for diverted water (at Casitas) and $60 per acre foot for direct use water (at Matilija). _MA~T.....I...L_IJ-.A_ DAM BENEFIT - COST ANALYSIS APRIL 1965 Introduction 1. As the result of their review of the Bechtel Corporation written report on the safety of Matilija Dam on March 30 31, 1965, the Board concluded that an economic analysis of the benefits of the dam for water conservation and flood control versus the costs of testing, repair, and operation of the dam should be submitted prior to April 20, 1965 to assist the Board in reaching a rational decision with re gard to demolition or repair of the dam. 2. In reply to a letter from the Director, Public Works dated April 1, 1965, the Bechtel Corporation furnished tlorder of rnagnitud~' estimates of cost and time for demolition, and repair of the dam. A copy of the Bechtel Corporation let ter dated April 10, 1965 is furnished as appendix itA". 3. By memorandum to the Director, Public Works dated AprilS, 1965, the chief flood control engineer furnished data indi cating that Matilija Dam cannot be depended upon to provide flood protection to downstream property during a major flood due to the relatively short time required to fill the reservoir. A copy of this memorandum is furnished as ap II pendix "B • 4. Data regarding benefits of Matilija Dam as a water conser vation facility as well as costs of operating the facility for this purpose were furnished by letter from the Ventura River Municipal Water District dated April 13, 1965. A copy of this letter is furnished as appendix lie". 5. Information regarding the estimated annual cost of liabil ity insurance for the dam was obtained from the county executive's office. The estimated costs are as follows: 1) For 180 day test period; $ 50,000 2) After repair of the dam; $100,000 Alternate Possible Courses of Action 1. The following are considered to be the most reasonable al ternate courses of action which might be taken to correct the unacceptable risk posed by the presently known facts regarding the condition of Matilija Dam: a) Remove the dam. b) Perform further tests and if condition of abutments is determined to be unacceptable, remove the dam. -2- c) Perform further tests and if condition of abutments is de~ermine4 to be acceptable, repair the dam by a) removal of upper 5 tiers of deteriorated con crete in the 8 center spillway bays. b) removal and replacement of deteriorated con crete as in (a). Estimates of First Costs and Annual Charges 1. Removal of dam a) First cost as per item (3), page 4 of appendix . "A" = $350, 000 b) Assuming that first cost will be satisfied by a 10 year loan at an interest rate of 4%, annual cost for 10 years will be 0.12329 x $350,000 = $ 43,300 If a 20 year bond issue at 4% interest is sold to cover this first cost, the annual cost over the 20 year period will be 0.07358 x $350,000 c $ 25,700 c) Removal of the dam will require that Flood Zone 1 assume the annual costs for principal and interest on the outstanding bonds originally issued for cori struction of the dam. These costs 'are shown in Table 1. Interest rate is 1-1/4%. (See Table 1 on page 3) ... -3- Table 1 Annual Costs for Amortization of Construction Bonds .. Fiscal Year Principal Interest Total Payment • 65-66 $100,000 $17,500 $117,500 66-67 100,000 16,250 116,250 67-68 100,OOe 15,000 115,000 68-69 100,000 13,750 .113,750 69-70 100,000 12,500 112,500 70-71 100,000 11,250 111,250 71-72 100,000 10,000 110,000 72-73 100,000 8,750 108,750 73-74 100,000 7,500 107,500 7L~-75 100,000 6,250 106,250 75-76 100,COO 5,000 105,000 76-77 100,000 3,750 103,750 77-78 100,000 2,500 102,500 78-79 100,000 1,250 101,250 Totals $~;_~.oO, 000 $131,250 $1,531,250 The equivalent average annual costs for amortization of the total bond costs over 10 and 20 year periods will be as follows: 1) 10 year period = 1,400,000 x 0.107 = $149,5CO 2) 20 year period = 1,400,000 x 0.05682 = $ 79,500 d) Total annual costs for the 10 and 20 year periods of time will be as follows: 1) 10 year period; 43,300 + 149,500 = $192,800 2) 20 year period; 25,700 + 79,500 == $105,200 e) The annual tax rates required to meet the annual 10 and 20 year costs, assuming an assessed valua tion of $150,000,000 in Flood Zone 1, will be $ .13/$100 and $.07/$100 respectively. -4- 2. ----Perform ----further ---tests -and -then remove -dam" a) The first costs involved will be those required for performaGce of the tests. These will include the . following: 1) Pumping water into reservoir ::: $ 70,000 (1) (2) 2) Installation of 36" blow-off valve = $ 20,000 (2) 3) Services of Bechtel during tests a $ 30,000 (3) 4) Services of VCFCD during tests = $ 10,000 5) Liability insurance during tests = $ 50,000 Total = $180,000 b) If this total cost is provided for by a 10 year loan at 4%, the annual cost for 10 years will be C.12329 x $180,000"' = $ 22,000 Assuming that this amount of money can be raised by a 20 year bond issue at 4% interest, the annual cost for 20 years will be 0.07358 x $180,000 ::: $ 13,200 c) Total annual costs for the 10 and 20 year periods of time will include those under l(b), l(c), and 2(b) above: 1) 10 year period; 43,300 + 149,500 + 22,000 = $214,800 2) 20 year period; 25,700 + 79,500 + 13,200 = $118,400 d) The annual tax rates required to meet the annual 10 and 20 year costs, assuming an assessed valuation of $150,000,000 in Flood Zone 1 will be $ .14/$100 and $ .08/$100 respectively. 3. Perform further tests and repair dam ~ removal of utter 5 tiers of deteriorateO-Concrete in the 8 center spi way '[oys. Remove dam at end of usefui1'ITe nO year and year perl.odS)':' - -- -- a) The first costs involved will be the same as those under l(a), l(c), and 2(a) above plus the repair cost of $400,000 shown in item 4, page 4, of appendix "An. Thus, total first cost will be 350,000 + 1,400,000 " + 180, 000 + 400,000 ;I $2,330,000 (1) estimate from V&~ (2) estimate from appendix "All (3) estimate by VCFCD -5- b) If the additional first cost of $400,000 is provided for by a 10 year loan at 4% interest, the annual cost for 10 years will be 0.12329 x 400,000 = $ 49,500 Assuming that the required funds will.be raised by a ..20 year bond issue at 4% interest, the annual cost for 20 y~ars will be 0.07358 x 400,000 = $ 29,500 c) Annual sinking fund costs at 3% interest required to provide for removal of the dam at the end of the 10 and 20 year periods of service are as follows: 1) 10 year period: 0.08723 x 350,000 x 1.344(1) = $41,000 2) 20 year period: 0.03722 x '350,000 x 1.806(1) = $23,500 d) Other annual costs to be considered include the annual cost of operation estimated by VRMWD at $5000 and the annual cost of liability insurance estimated at $100,000. e) Total annual costs for the 10 and 20 year periods of time 'o1i11 include those under l(c), 2(b), 3(b), 3(c), and 3(d) above: 1) 10 year period: 149,500 + 22,000 + 49,500 + 41,000 + 105,000 = $367,000 2) 20 year period: 79,500 + 13,200 + 29,500 + 23,500 + 105,000 == $160,7eO 4. Perform further tests ~ repair dam £y removal. and r~Slace ~ of upoer 5 ti~rs 2£ deteriorated concrete ~ the _ center sEi!lwa bays. Remove dam ~ end of userul life (10 year and 2nyear periods). a) The first costs involved will be the same as those under 3(a) above plus the increased cost of the repair work ($600,000 as shown in item 5, page 4 of appen dix riA" less the $400,000 cost of repair included in 3(a». Thus total first cost will be 2,280,000 ;. 200,000 = $2,480,OOC b) If the additional first cost of $200,000 is provided for by a 10 year loan at 4% interest, the annual cost for 10 years will be 0.12329 x 200,000 = $24,700 Assuming that the required funds will be raised by a 20 year bond issue at 4% interest, the annual cost for 20 years will be 0.07358 x 200,000 = $14,700 c) Total annual costs for the 10 and 20 year periods of time will include those under 3(a) and 4(b) above: 1) 10 year period: 367,000 + 24,700 = $391,700 2) 20 year period: 160,700 + 14,700 I: $174,400 (1) Cost for removal of dam assumed to escalate at 3% per year -6- Estimates of Benefits Provided by Dam 1. Water conservation benefits a) With the storage capacity of the dam reduced by rewov- ·-a1 of the upper 5 tiers of concrete in the 8 center spillway bays, the estimated annual value of the water conserved for beneficial use as shown in the enclosure to appendix "ell is $156,070. b) With .the dam repaired for full storage, the estimated annual value of the water conserved for beneficial use as shown in the enclosure to appendix "e" is $205,200. Summary of Costs and Benefits 1. The annual costs and benefits associated with each of the alternate possible courses of action are summarized in Table 2 on page 8. :Jiscussion 1. The data summarized in Table 2 indicates that further test ing and subsequent repair of the dam are economically· justi fied only if the testing indicates that a useful life of at least 20 years can be realized from repair of the dam. However, in view of the high annual costs which must be borne by Flood Zone I if the dam is removed, it is con sidered pertinent to analyze the annual costs which might devolve upon the Zone if the dam were to be tested and ra paired at Zone expense and then transferred to the Ventura River Municipal Water District. On the basis of a 10 yea~ useful life and repair of the dam to full capacity the an nual costs to the Zone for testing and repair of the dam "t'lill be $22, COO. plus $74, 200 or a total of $96,200. If the period of useful life is determined to be 20 years rather than 10 years, the annual costs to the Zone will be $13,200 plus $44,200 or a total of $57,400. These annual costs to Flood Zone 1 make it very obvious that it would b~ to the advantage of the Zone to test and repair the dam and then transfer it to VRMtID; however, unless the dam could be repaired for a useful life of 20 years, it is q,uestionable wh~ther VRMtID would agree to accept ownership of the ~acility. 2. ~e3ardless of whether action is taken to re~ove the dam now o~ to p~oceed with further testing and repairs, it must ba rcco3niz~d that the time requirements for icplernentation of either action will not penJit the removal or repair of th~ daw prior to the next storm season. Immediate action to remove the dam would undoubtadly result in some partial re r~oval of the structure prior to next November - possibly the upper 5 tiers of deterior~t~d concrete - and thereby reduce in some ceasure the hazard to life and property downstrea~ -7- from the dam. However, without further testing to deter nina the condition of the abutments, prudence would require evacuation of the downstream flood plain whenever storm con ditions might indicate possible filling of the reservoir. IE further testing is conducted and the condition of the abutments is found to be satisfactory, the risk of riding out another storm season would be greatly minimized. If the condition'of the abutments' is found to be unsatisfactory, the hazard to life and property downstream from the dam will not be appreciably greater than would exist with partial re moval of thc! dam as discussed above and because of the more definitive knowledge of the situation, protective action during storm conditions would tend to be more decisive. TABLE 2 SUMMARIZATION OF ANNUAL COSTS AND BENEFITS lO-Year Period 20-Year Period . .Annual Annual Benefit-Cost 1 Annual Annual Benefit-,Cost Costs Benefits Ratio Costs Benefits Ratio - Dam Removed 192,800 0 0 "105,200 0 0 '. -Ul Tested - Then 214,800 0 0 118,400 0 0 A,emoved .. . Dam Tested - Repaired 367,000 156,070 * 0.43 250,700 156,070* 0.62 For Reduced Capacity 367,000 251,390** 0.69' 250,700' . 251,390** 1.00 - Dam Tested - Repaired 391,700 205,200* 0.53 265,400 205,200* 0.78 For Ful~ Capacity 391,700 328,520** B.84 265,400 328,520** 1.24 , v -9- Conclusions 1. Recoval of Matilija Dam will provide no positive benefits to Flood Zone 1 and will involve annual costs to the Zone of $~92,800 for 10 years ~r $105,000 for 20 years. 2. ~epair of the dam for a useful life of 10 years is not economically justified by the value of water which could b~ conserved for use in the Zone. However, it· would be advantageous to Flood Zone 1 to pay for testing and repair of the·dam for a useful life of 10 years if ~'fi~ would agree to accept ownership of the dam and.responsibility for all other costs upon completion of repairs. 3. Repair of the dam to provide full reservoir capacity for a useful life of 20 years is economically justified by the value of water which could be conserved for use in the Zone. ~owever, in view of the prospect of continuing deteriora tion of the concrete, planning for a useful life of 20 years appaars to be overly optimistic. 4. Time requirements for removal or for testing and' repair of. the dao preclude elimination of the hazard posed by the possible unsatisfactory condition of the abutments prior to the next storm season. Accordingly, arrangements must be made to provide for liability insurance and other con tingencies for at least another year. Reco~r.1endati.ons 1. As the first action of the Board, it is recommended that i~mediata negotiations be conducted with the Ventura River j:-iunicipal Hater District for purposes of entering into an agreement providing that VRHtID will accept ownership of the cam and responsibility for paying off the outstanding bonded indebtedness as well as all other operating expenses if the dam is repaired for a useful liie of 10 years or better at Ventura County Flood Control District expense. 2. If the negotiations with Ventura River Municipal Water District are successful, it is recommended that the Board then take appropriate action to obtain VOter approval for a 10 year loan of funds or a 20 year bond issue in a su£- 1icient awount to cover tasting and repair of the d&u. . Only funds actually required for testing should be borrow- ~d initially. Subsequent borrowin& upon completion ot test ing should then be in an amount suxficient for either removal or repair of the dam as the case may be.