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; ; 1956 Water Supply and Distribution System Report; 1956-01-30
REPORT on WATER SUPPLY AND DISTRIBUTION SYSTEM For the CARLSBAD MUNICIPAL WATER DISTRICT By S. T. HARDING Consulting Engineer January 30, 1956 TABLE OF CONTENTS Conclusions and Recomendations .»•>....<•»....• 1 Introduction . » ...... . .......... 10 Policies of San Die^o County Water Authority ......... 13 Back Taxes to be Paid, on Annexation .......... 13 Construction of Branches ......... ...»•• 14 Record on Annexations and Annexation Policy ........ 19 Sice of Annexing Units ............... 20 Water Requirements of the Authority ...*•• ..... . 22 Uatsr Supply of San Diego County Water Authority . » ...... 23 Colorado River Supply ....... ..... ... 25 Feather Paver Project ... ............ 28 Other Sources ..... ...•«....».. 31 Conclusions on Water Supply of bh« Authority ....... 32 Preferential Rights ................. 34 Surplus Sei-vice within the San Diego County Water Authority .... 38 Summary of Water Supply Obtainable by the Carlsbad Municipal Water District from the Colorado River Supply of the Authority .... 43 Local Water Supplies of Carlsbad Municipal Water District .... 44 Mission Basin Supply ..... ........ ». 45 Summary of Total Water supply of Carlsbad Municipal Water District . . 51 Water Requirements ......... ........ 53 Connection to Fallbrook-Oceanside Branch .......... 54 Alternate Routes for Conduits to Aqueduct ...... ^ ... 58 Capacity of an Initial Conduit to the Aqueduct ...... .. 62 Works Constructed Jointly with Other Units .......... 66 Local Storage .. ... ....... ....... 68 Conditions Within the Carlsbad Municipal Water District ..... 71 Recomended Program ........... ....... 74 CONCLUSIONS AND RECOMMENDATIONS The situation confronting the Gailsbad Municipal Water District is so complex and the uncertainties affecting the matters on which policy and action d3cisions must be based are so numerous that it is not surprising that local differences of opinion have developed regarding the actions which the District should take. No engineering report can resolve these uncertainties. However, the existing conditions can be reviewed and the water supplies which may b e available to the District analysed. For any given water supply a selection of the aize and location of conduits for its conveyance to the District car. be made. 'The following report attempts to approach this situation on the above basis. To present the material required in reaching the conclusions resulting from this review adequately so that this support can be understood requires a report of considerable length. The interrelation of the separate matters makes it dif- ficult to reach independent conclusions on each subject. Consequently this sum- mary has been prepared expressing the author*s conclusions without thair support. The support will be found in the more lengthy report which follows. The recom- mendations resulting from these conclusions, including a proposed program, are also included in this summary. 1. The Carlsbad Municipal Water District is a legally organized agency contain- ing 21,000 acres of which present development extends over a gross area of about 5>000 acres with actual use of water on about 2,000 acres. 2. There are now available to a part of the area of the District a water sup- ply of about 2,000 to 2,500 acre feet per year from wells in the Mission Basin and 300 to 500 acre feet per year from wells within the District. 3« The ultimate water requirements of the District are about 24,000 acre feet per year. 4» For full developpsnt the District will need an additional supply of at least 20,000 acre feet. 5. There are no local sources from which this additional need can be supplied. 6. The only agency, existing or prospective, to which the District can look to secure this additional supply is tne San Piego County Water Authority acting, to date, as a member agency of the Metropolitan Water District of Southern California. 7. The water supply wliich the District can expect to secure from the Authority is controlled by the available supply of the Authority and the policies which it adopts and actions which it takes. The Authority is fimilarly limited by the policies and actions of the Metropolitan Water District. 8. The water supply nov: available to the Authority is limited to its entitle- ment in the Colorado River supply of the Metropolitan Water District or such additional temporarily available parts of that supply as other Metropolitan Water District units may not,, as yet, use. 9 The entitlement of the Authority in this Colorado River supply is 112,000 acre feet per year* This entitlement may be enforced when the total Metro- politan Water District demands equal its total entitlement from the Colorado River. 10. The capacity of the present two barrels of the Authority's aqueduct is about 140,000 acre feet per year. This represents continuous operation at capacity. 11. The County Authority act provides that each member agency is entitled, as a preferential right, to receive at any time the same percentage of the total water supply of the Authority that the total accumulated taxes paid to the Authority by that agency to date bear to the total accumulated taxes paid to date by all angencies in the Authority. 3 12. While it is hoped that the Metropolitan Water District or other agency will secure and deliver additional water to its area at or before the time when the supplies now available are fully used, there is no assurance that this can or will be accomplished. 13. Temporary development in the District by the use of temporarily available surplus Colorado River supplies, whose use may later be restricted if ad- ditional supplies are not secured, is not in the interest of the users or the District. 14c There are widely divergent views on the rate that the present use will increase and the time ;-/hen all presently available sources of water supply will be fully used. The more rapidly present sources are used the greater is the risk that present sources will be inadequate before additional water is se«- cured. The last report of the engineer of the Authority represents a rapid rate in the increase in demand; the report of the Board of Engineers is more conservative. The time when the present Colorado River entitlement of the M.WoD. may be fully used has been gem-ally estimated as from 1970 to 1975 by the state and other estimators. It is my opinion that delivery of a substantial outside source of additional water into the Coastal area of southern California by 1975 represents an optomistic forecast of what can be accomplished. 15 . It is my conclusion that the Carlsbad Municipal Water District should not undertake development in excess of that which can be supplied from its local supplies and its dependable supply from the present Authority aque- duct until plans for additional water have become definite and conetruction is under way with a date of completion set on which reliance can be placed. 16« On the above basis the most important item in the selection of the size of a conduit to the aqueduct of the Authority is the water supply the District 4 may secure from the present Colorado River supply of the Authority. 17. The .preferential right of the District in 1954 was 1.21 percent. The assessed value of the District fes nearly doubled in 1955 as a result of the construction of the Encina power plant. Ths Districts preferential right should continue to increase over the coining years. 18. The preferential right of the District will not increase as rapidly as its increase in percentage of total assessed value as the preferential right is based on accumulated taxes paid. The units which joined the Authority initially and had larger assessed values then will continue to retain an advantage in the amounts of their preferential rights. 3-9. From comparisons of the estimates of the rate at which the assesvsed values of the District and the Authority may increase it is concluded that the preferential right of the District may reach three percent and might pos- sibly reach four percent. 20. The 1954 preferential right of the District applied to the present aque- duct capacity represents a supply of 1,670 acre feet per year. It is con- cluded that by I960 the preferential right may reach 2,800 acre feet., In 1970, if the Authority is then limited to 112,000 acre feet of Colorado River water the District might secure 3,500 acre feet, and tinder more favorable but less probable assumptions 4,500 qcre feet. 21. If in 1970 the Metropolitan Water District is able to supply the full capacity of the San Diego Aqueduct of about 140,000 acre feet per year, the preferential right may be 4^200 acre feet for the more probable conditions and 5,600 acre feet for more favorable but less probable conditions. 22. Until the other member units of the Authority may require their full preferential rights, surplus water may be obtainable. The District might be able to secure 5,500 acre feet from the Aqueduct in I960 if the local supplies are then able to supply their mean safe yield. From I960 to perhaps 1970 the supply the District may secure may be expected to vary between 4,000 and 5,000 ac ft per year. 23o The monthly variations in water demand result in an annual pipe line delivery for the year of about one-half the volume represented by its continued flow at capacity. For a pipe line diverting from the aqueduct without storage regulation the size of the pipe should be selected to be able to carry about twice the mean annual rate of use. 24. Three routes for pipe lines from the aqueduct have been considered and cost estimates prepared. A comparison of these results shows that the so- called Rod line or San Marcos route has the lowest cost and provides the best delivery service. 25. Estimates for pipe lines of five different sizes have been prepared by Mr. Short. These range in annual delivery capacity from 900 to 17,000 acre feet. Estimates for three intermediate sizes have been interpolated from these results. 26. It is concluded that the most desirable line for present construction is one having a diameter of 20 inches, a maximum flow capacity of 17 sec ft, and an annual delivery capacity of 6,000 acre feet. The interpQlated estimated cost of this line is $1,150,000. It would extend from the aque- duct to Mt. Kelly, passing Point D en route but would not include any branches. 27. The District might secure the delivery of part of its present pregerential right by constructing a connection to the Fallbrook-Oceanside Branch. This was suggested as a possibility to meet the time limits on the expiration of the joint use agreement with Oceanside, Now that agreement on the terms for the extension of this agreement has been reached, such a connection to the Fallbrook-Oceanside Branch should not be made unless it again becomes a matter of emergency relief. Within the time of the extended Oceanside agreement, the District can seek and should find a direct method for sec\ir- ing all of its preferential right in Colorado Ritrer water* 28. To secure full use of its preferential right, the District will need storage. Such storage can be within or adjacent to the District or may be secured by use of .Authority storage in San Vicente by exchange. 29. The proposed outside sources of additional water are reviewed in the main report. The most definite is the proposed Feather River Project. There are essential basic policies and organizational matters to be determined be- fore this project can expect to secure approval for the issuance of general obligation state bonds to meet its costs. It is concluded that the Dis- trict is not justified in undertaking, at this time, any use of water whose permanence is dependent on the realisation of present hopes for this project. Such dependence on this project shouHwait until hopes may be replaced with at least a reasonable prospect of reality. Other plans for additional water are even less definite. 30. The difficulties of the Carlsbad Municipal Water District are increased by the present policies of the Authority relating to requirements for annexation and to construction of branches. Original units in the Authority were ad- mitted with boundaries limited to partly developed areas needing supplemental water. Branches were constructed to all original units at Authority cost. The Carlsbad District was required to include an area of undeveloped land tiuree times the size of its area needing supplemental water at this time as a condition of annexation. To increase the District's burden, the Authority now gives no assistance in the construction of branches- These policies, in my opinion, are short sighted and detrimental to the Authority and to the recently annexed units. They are particularly disadvantageous to the Carlsbad Municipal Water District which has the obligation to serve areas of raw land for which the Authority is not able to provide an assured water supply. It is probably too late to make material changes in the District boundries. However, the policies relating to branches can be changed at the discretion of the Board of the Authority. A reasonable and equitable basis for dividing costs of branches serving more than one unit was proposed by the Board of Engineers on July 19, 1955» This policy was re jected by the Board of the Authority on August 18$ 1955* The Carlsbad Municipal Water District would be most economically served by the proposed San Marcos Branch which would also serve five other areas * It is unfor- tunate that the present policy places all of the burden of securing its water supply from the Aqueduct on the Cerl0bad Mtmicipal Wstar Di0trict without assistance from the Authority. Such assistance by the Authority is essential if the problems of joint use by several units are to be worked out. The present position of the Authority requires the Carlsbad Municipal Water District to proceed by itself with a pipe line which is uneconomical in relation to what could be secured by a joint branch. Recommended Program The following program for the Carlsbad Municipal Water District is recommended. 1 - Instruct its engineer to proceed with the investigations needed to prepare plans for a 20 inch pipe line along the Red or San Marcos route from the aqueduct past Point D to Mt. Kelly with sufficient detail to provide estimates of cost that will assure that the line can be built within the estimate. 2 - Proceed with preparations for a bond issue to provide funds for the cost of the above line and call and hold an election for the approval of such bonds as general district obligations. 3 - Approve connection to such a line by local areas within the District seeking to use the water it will provide with the costs of such connections or ex- tensions to be met by such local areas, with such local areas organized as improvement districts or other forms approved by the Carlsbad Municipal Water District. 4 - Operate the District*s pipe line on a toll basis with the tolls set so as to return as nearly as may be practicable the costs to the district for its pipe line. -This will result in placing the security of the entire district behind the bond issi;e but will place the cost for the line on ths parts of the District using the water. As the District has no source from which it can, at this time, secure a water supply for its entire area, the tax burden on the lands which cannot be served should be kept at a ndnimum. 5 - Proceed actively with this program under a schedule which will enable the construction of this pipe line to be completed by December 31, 1956 so that it may be in service when the extended agreement with Oceanside expires. 6 - Concurrently continue to seek local storage sites at which up to 4000 acre feet may be stored at reasonable cost and efficiency in the use of water. The pipe line proposed plus the storage that can be secured by use of storage space in San Vincente Reservoir should meet District demands for a long enough time to enable local storage opportunities to be thoroughly investigated. 9 The construction of such local storage, if found to be feasible, represents the most desirable next step in the District's program. 7 » Work out concurrently the change in form of the organization, if any, which it is considered may be desirable for the present area served by the Carlsbad Mutual Water Company. 8 - Take any steps necessary to preserve the present rights and water supply used in the District of waters from Mission Basin emphasizing a willingness to work cooperatively with any group ar agency seeking settlement of present differences or methods of securing additional water. 10 MAIN REPORT INTRODUCTION This report represents the results of the investigations and conclusions of its author. Its preparation was undertaken at the request of the Carlsbad Municipal Water District, November 7 to 12 and December 5 to 7, 1955 were spent in local investigations and discussions. On December 6, 1955 a verbal report covering preliminary conclusions of the author was made at a meeting of the District Board and other interested local parties. The author was requested by the Board to complete his report, including recommendations regarding the route and capacity of a conduit from the Authority Aqueduct to the District. It was the initial program that this report would be submitted by December 15, 1955* At that time the agreement for joint use of pipe lines with the City of Oceanside extended only to June 30, 1956 and prompt action on some District program was urgently required. The verbal report for December 6, 1955 was directed mainly at this situation. The extension of the agreement for joint use with Oceanside has, to some extent, relieved this urgency. However, the time of this extension is insufficient to remove the need for definite and prompt action on the part of the District. The author was requested to indicate to the District the additional field investigations and estimates that might be needed to enable him to reach con- clusions on the matters to be covered by his report. Such investigations and estimates were to be made by the engineer of the District. It was found that some additional estimates were needed in considering alternate conduit routes. These were prepared by the District Engineer, Mr. Short, and have been used as the basis of the authors conclusions in this report. The time of completion 11 of the report was extended until after this material had been prepared and furnished to the author. It was received on January 19> 1956• The need for a report such as that which is attempted here arises both from the physical situation in the District and from the present differences of opinion among local interests in regard to the extent and type of development that should be undertaken at this time« The selection between the several pro- grams which the District might follow would be a difficult question even where past differences of opinion did not exist. Where different local interests have already become committed to the support of divergent programs, the reconciliation of these differences is increasingly difficult. The failure of the bond election in 1955 to carry appears to have emphasized some of these differences. Regardless of what program may be adopted, an essential to its success will be its acceptance and support by a substantial majority of those to be served and to become liable for the payment of its cost. The problems of the Carlsbad Municipal Water District are not limited to its internal operations. Like other units of the San Diego County Water Authority it is subject to the policies of the Authority. The San Diego County Water Author- ity, in turn, is only one agency in the Metropolitan Water District of Southern California and is subject to its policies. The present policies of the San Diego County Water Authority regarding size and character of areas which it will accept for annexation, regarding the construction of branches and on allocation of available water supplies are all major factors in determining policies which the Carlsbad Municipal Water District may adopt and under which it may operate. Similarly the policies the Metropolitan District may enforce on its agencies, regarding the water it has or will secure and the construction of facilities for its delivery to its agencies, control what the San Diego County 12 Water Authority can do for its unitso These matters are discussed at some length in this report. The present policies of these two general agencies, in my opinion, increases and make more difficult the solution of the internal problems of those units which are now largely undeveloped. Where so much difference of opinion exists among the local interests most directly affected by the program which the District may adopt, it is to be expected that similar differences will extend to the conclusions reached by any outside engineer employed in an attempt to find a program which may receive general acceptance. Such differences have occured in the various discussions in which the author has participated. All discussions have been frank, and in my opinion, have been sincere. Where discussions are frank and sincere they may be very helpful in reaching solutions even though such differences exist. In the preparation of this report I have received the full assistance of all of those with whom I have worked. Such assistance is essential in the making of such a reportj its helpfulness to me is gratefully acknowledged. There are certain existing facts and conditions which cannot or will not be changed. Any program which the District may adopt must be based on the acceptance of these facts. These include: 1- - The Carlsbad Munucipal Water District is a legally established public agency responsible for seeking and, if reasonably possible, for securing a water supply sufficient to meet the requirements of its entire area under full develop- ment. 2 - The Carlsbad Municipal Water District is a unit of the San Diego County Water Authority and subject to both the obligations and benefits which result from this membership. 3 - Any program which the Carlsbad Municipal Water District may adopt must be worked out within the framework of the District and the Authority as they 13 now exist subject only to such policy changes as may occur within these existing agencies. As stated, decisions made by the Carlsbad Municipal Water District must conform to the conditions and limitations resulting from its membership in the Authority just as the Authority must similarly conform to the conditions and limitations resulting from its membership in the Metropolitan Water District. For this reason it has seemed to be preferable to discuss first the generalfacts and policies of these two general agencies before preceding to the discussion of the Carlsbad Municipal Water District and its internal matters. This general sequence has been followed in the report which follows. POLICIES OF THE SAN DIEGO COUNTY WATER AUTHORITY As a member of the San Diego County Water Authority, the Carlsbad Municipal Water District is subject to its requirements. Some of these requirements are the result of provisions of the County Water Authority act but the main ones affecting present problems are the result of policies which have been adopted by the County Water Authority and which can be modified by its own action. _Back Taxes to be Paid on Annexation One policy is that all newly joining units must make up the equivalent pf the taxes it would have paid if it had been a member from the time of the organization of the Authority. This policy is based on the similar practice of the Metropolitan Water District for members newly joining that district. The County Water Authority was subject to this requirement when it joined the Metropolitan District. The amounts of such back taxes have been fixed and accepted by the Carlsbad Municipal Water District. The total amount to be paid under the terms of 14 annexation, as shown in the 8th Annual Report of the San Diego County Water Authority was $57,700. Of this total $48,286.04 remained to be paid on June 30, 1954» There are no remaining questions regarding this item. The Carlsbad Municipal Water District has agreed to pay it and is in the process of paying it in annual installments. The general principle on which it is based is equitable. Construction of Branches The present policy of the San Diego County Water Authority on connections to the aqueduct is to supply one outlet per member unit at Authority expense and to require the unit members to construct all branches required to convey water from the aqueduct to the unit. Where two or more members may build a branch jointly, the Authority will take over its operation and supervise the division of flow between the participating units. The branch lines needed to deliver water to each of the then Authority members were discussed in the First Annual Report, pages 102-110. The policy there recommended of constructing branch lines to each of these original units at Authority expense was adopted and $2,000,000 of Authority bonds for this pur- pose were approved at an election held November 5» 1946. These lines included the Fallbrook-Oceanside line to these member units at an estimated cost to the Authority of $600,000 (Second Annual Report pp 46 and 58). The Fallbrook- Oceanside Branch is listed in the Authority assets at $814,203.14 in the Third Annual Report (p. 58). On May 13, 1948 the Board of the Authority passed a resolution which is quoted in the Eighth Annual Report (p. 21) as follows: "It was moved by Director Beck, seconded by Director Shelton and unanimously carried that the Board adopt the policy that annexing agencies must construct at their own expense the required connecting lines to the Authority's worksj and should the point of delivery of water by the 15 authority be other than the point of connection, the line from connection to the point of delivery mast be constructed to the Authority's approval and, upon completion, be turned over to the Authority for operation and maintenance." This resolution is not specific regarding who would pay operation and maintenance costs after acceptance by the Authority; presumably such costs would be paid by the Authority. The resolution is specific in placing the first cost entirely on the members served without participation in construction cost by the Authority. In his June 1955 report Mr. Holmgren discusses the branch lines needed to serve the present and pending area of the Authority (p03^)« The report describes a San Marcos Branch and Sub-branch from which the Carlsbad Municipal Water District would be served. This branch would also serve five other units of the Authority. This report includes a "tentative Construction Program" which "\vill provide the facilities to meet the estimated demand of member agencies for water from the Authority up tp the year 1970." In this program the branches needed are listed together with the construction of the Second Aqueduct. Three plans are described which the Authority might follow varying from building the Second Aqueduct only to building all of the branches listed. Mr. Holmgren does not commit himself regarding which plan should be followed. He states "The extent of Authority participation depends entirely on the policy which the Board adopts in respect to serving water to the areas remote from the Aqueduct. On July 19, 1955 the Rincon Del Diablo Municipal Water Districtrequested aid from the San Diego County Water Authority in the construction of laterals and storage. This was considered by the Board on July 21, 1955 and referred to the Water Problems and Engineering and Operationa Committees. Previously on July 14, 1955 the Board of Engineers had met with the Authority's Engineering and Operations Committee and the General Manager and 16 discussed policy regarding construction and operation of branch lines. On July 19* 1955 the Board of Engineers made its recommendations regarding such policy. These recomendations are as follows: 1. Include in the Authority System only those Branch Lines necessarily required by the Authority in supplying water to two or more Agencies. 2. Authority will finance or construct, and own, maintain and operate such a Branch Line with a pipe line capacity equal to that part of the then available aqueduct capacity to which the Agencies involved would be entitled in accordance with their preferential rights as defined in Section 5 (11) of the County Water Authority Act. 3. Should Agencies to be served by any such Branch Line desire to have a pipe line capacity greater than that defined in Item 2, the Authority will con~ tribute to the cost of such Branch Line with the desired greater capacity. The cost of construction of such a line to be divided between the Authority and the Agencies to be served from the Branch; the Authority to assume that part which the sum of the preferential rights of the Agencies involved, as outlined in Item 2, bears to the total capacity as actually provided in the Branch. The balance of the cost of such Branch Line to be assumed by the Agencies involved and paid in accordance with terms approved by the Authority. The Authority will own, operate and maintain such line but replacement costs are to be financed in the same manner as original costs. 4» Authority to determine or approve the location of all Branch Lines. 5. When regulating reservoirs are required at a later date, they are to be financed and operated in the same general manner as specified in the previous items for Branch Lines. 6. Agencies will take their supplies from such Branch Lines (or reservoirs) and distribute this water to their respective service areas. ?• Agencies are to provide, own, operate and maintain any pumping plants required for boosting the supply to elevations higher than the hydraulic grade 17 line provided in a Branch Line reservoir. 8c As preferential rights of individual Agencies change from time to time, due to development of lands within the Agencies, or due to providing of additional aqueduct capacity, corresponding adjustments are to be made in the distribution of the costs of Branch Lines previously constructed« On August 18, 1955 the Board of the Authority took the following action - "that the Board of Directors reaffirm the present policy of the Water Authority to the effect that any lines necessary to serve member agencies shall be constructed at the expense of such agencies, provided that if the agencies elect to take delivery at a location other than the aqueduct, thay shall finance the construction of a line from such point of delivery to the aqueduct, and upon completion turn over such line to the Authority for operation and maintenance»M This action is expressed in terms of plural agencies and presumably confirms the resolution of May 13, 1948. Where a single agency constructs a line to the Aqueduct it is understood that delivery would be at the Aqueduct and that the single agency would not only have to construct the line but would also operate it. The present position of the Authority extends no assistance to any member unit recently annexed in the drlivery of water from the Aqueduct, Such units vary from locations along the Aqueduct to some nine miles from its boundary to the Aqueduct in the case of the Carlsbad Municipal Water District. Oceanside, Carlsbad's neighbor, as an original unit had a branch for its service constructed to its vicinity by the Authority at over-all Authority cost. The Carlsbad Municipal Water District is meeting the equivalent taxes which it would have paid if it had been an original unit and is being required to finance all costs of its own service except that it has been given permission to connect to the Fallbrook- Oceanside Branch in which there is only part time surplus capacity. In its resolution of August 18, 1955 the Board of the Authority rejected the recommendations of its Board of Engineers. The eight points in these recom- mendations represent, in my opinion, an equitable adjustment of this problem. 18 The Board of Engineers recomended that the Authority construct only those branches serving more than one agency. The Can Marcos Branch as planned by Mr Holmgren would serve six agencies. The Authority would meet only the part of the cost of branches represented by the delivery of the preferential rights of the agencies "of the then available aqueduct capacity" (2) with later adjustments as prefer- ential rights may change (8). Mr. Holmgren states in his June 1955 report that the original branches were constructed to a general capacity of 1^ times the preferential rights of the agencies served(p 28). The Board of Engineers recommended that for new branches the assistance extended to the agencies to be served shoiild be only 2/3 of of the basis used for the original branches; the Board of the Authority disapproved this recommended assistance. The policy relating to construction of branches is related to the prob- lems resulting from requiring agencies seeking annexation to include large areas of undeveloped land in order to secure annexation for the areas now partially developed and needing supplemental water. If the Authority requires newly annexing units to assume the burden of such undeveloped land, there is even more justification for the Authority to extend to the annexed unit financial assistance in the construction of its initial conduit system. Even a policy under whic,h the Authority participates in the cost of of branches to be used by more than on Authority agency would be/limited assistance to the Carlsbad Municipal Water District unless the Authority is willing to of participate in such costs before all/the units to be served are prepared to receive service. The San Marcos Branch proposed by Mr. Holmgren would serve two areas not then organized for annexation to the Authority. The Carlsbad Municipal Water District will need all of its financial capacity to finance a branch for its own use and cannot furnish advance financing for branches which may later be used by other agencies. The Authority can carry such costs 19 until they may be used. If the Authority accepts the obligations which result from its approval of the annexation of new units, it should be prepared to participate in the construction of jointly used works to the extent of their construction before participati ng units may be prepared to use the water. Record on Annexation and Annexation Policy The basis for the inclusion of the areas forming the San Diego County Water Authority and the changing policies that have been followed since 1946 are well described in Resolution No. 376 of the Authority adopted January 12, 1956o The policy on annexation is closely related to the policy and program regarding securing additional future water supplies to meet the expanding needs of an enlarged Authority. Annexations that have been made may have been pre- mature in relation to assurances that witer would be available for use of the annexed areas when needed. This may have been the result of over optimism regarding the availability and obtainability of additional water supply. The record of expansion of both the Authority and the Metropolitan Water District speaks for itself. The results for the Authority operation to date are as follows (Holmgren*s June 1955 report p 2) Acres Original Authority area 133,392 Annexed 1944 to 1953 - 29,605 Annexed 1953 to 1955 188,700 Annexation under consideration 138,340 Total 490,037 The area actually annexed represents 1.6 the original area with an additional area slightly larger than the original awaiting completion of annexation procedure. There have been no similar expansion in the assured water supply of the Authority over the years when these increases in area have occured. Additions 20 were limited until 1953. The change in the rate of annexation follows closely after the issuance of its so-called "Laguna Declaration" by the Metropolitan Water District on December 12, 1952. The responsibility for this change is con- sidered by the Authority to rest with the Metropolitan Water District. There is room for argument regarding the extent to which the Metropolitan Water District had assumed a binding responsibility for both securing and dis- tributing water for all areas accepted for annexation when and as the develop- ment of such areas might require such water. Such arguments lose importance in the face of the situation which now exists. The essential issue is not what the Metropolitan Water District may have indicated it expected to do. This has been recognized by the Authority in its Resolution No. 376 which calls on the Metropolitan Water District to fulfill the committments of its past action. The direct response by the Metropolitan Water District to this resolution will have much more importance to the Authority than any interpretations of past expres- sions of the Metropolitan Water District. Sige of Annexing Units Any area desiring to joint the San Diego County Water Authority must secure approval of its proposed boundaries by the San Diego County Water Authority as a condition of its acceptance as a member. The same policy is enforced by the Metropolitan Water District. This policy is extended to changes in boundaries of existing members except that under present statutes incorporated cities have control of the changes in their own boundaries. This policy requires the approval of both the San Diego County Water Authority and the Metropolitan Water District of the boundaries of any new member unit. Neither agency is compelled to accept new members so that both the Authority and the Metropolitan Water District practically have veto powers regarding the location and size of new member units which may be accepted. 21 Since the Metropolitan Water District recently adopted its policy of encouraged expansion into areas of limited present development, it has also followed a policy of requiring new units to be relativly largee size in order to avoid too large a Board of Directors and too many deliveries to such units. The San Diego County Water Authority has followed a similar practice. The recent annexations to the San Diego County Water Authority have been in units which comprised the entire areas in sections of the county. Unit members have been required to include relatively large areas of undeveloped land where a developed area has sought annexation in order to secure supplemental water. Some unit members have formed which consist almost wholly of undeveloped 3.and. This policy has convenience for the San Diego County Water Authority but creates additional difficulties for the units containing a large proportion of undeveloped land. Such inclusion results in an implied, if not an actual, legal obligation to secure a water supply for the entire included area. There is a similar obligation to provide means of delivering water throughout the district. As the undeveloped land can offer only limited security for the financing of the cost of such 'init works, the inclusion of such raw lands, with lands now developed and needing only supplemental water, creates conditions under which the financial load to be assumed by the developed land for full unit development may exceed its resourses even though the developed lands, if in a separate unit, could offer adequate security for their own improvement. The Carlsbad Municipal Water District is in an intermediate position in regard to the extent of its developed and undeveloped lands. Its proportion of raw land is much greater than that of Oceanside which joined the original Authority with only its municipal area. On the other hand the developed area under the Carlsbad Mutual Water Company represents a larger assessed value 22 relative to the total area in the Carlsbad Muncipal Water District than is the case for seme of the higher units in the northern portion of the country. In order to secure annexation to the Authority the Carlsbad Municipal Water District was required to include 21,000 acres in its boundaries. The conditions in this area are discussed in a later portion of this report. In general the total area is about five times that now partially developed and nearly 10 times the area actually using water. The Carlsbad Municipal Water District is an existing legal entity with defined boundaries. The problems of the area needing supplemental water would have been very materially reduced if this area could have joined the Authority and worked out its development without having to assume the more difficult problems of the raw lands. WATER REQUIREMENTS OF THE AUTHORITY In his June 1955 report, Mr. Holmgren shows a 1955 water requirement for the then area of the Authority and pending annexations of 182,000 acre feet (Table 1, Col 5 plus Col 9). The ultimate requirement of this area is estimated to be 556,200 acre feet. Between 1955 and 1970 Mr. Holmgren lists estimated requirements for several years., His estimate for 1970 is 365»400 acre feet. In the estimates for all years, a constant local safe yield of 98,600 acre feet per year is included. The remainder of the requirement would have to be met from some source of imported water. Mr. Holmgren also includes in Table 1 an estimate of the water requirement of unorganized areas that may be annexed to the Authority. This total require- ment is 120,300 acre feet per year of which only 8,000 acre feet would be supplied from local sources. Use by these areas of Authority water is listed 23 to start in 1970. As shown later the entitlement of the Authority in the Colorado River supply of the Metropolitan Water District is 112,000 acre feet per year and the capacity of the present Aqueduct is about 140,000 acre feet. The Metropolitan Water District presently has no other source of water except its Colorado River supply and itself includes areas having a total ultimate demand in excess of this source. The San Diego County Water Authority now includes areas having an estimated ultimate requirement of 457,600 acre feet in excess of the safe yield of its local supplies. This requirement is over four times the Colorado River entitle- ment of the Authority and over three times the present aqueduct capacity. The estimated demand on the Aqueduct in 1970 is 2.4 and 1.9 times the entitlement and capacity respectively. In addition Mr. Holmgren lists potential annexations having a requirement equal to the Authority's entitlement in the Colorado River supply. The Board of Engineers concluded that the estimated ultimate water require- ments for the suggested service, areas appears to be reasonable, but differed from Mr. Holmgren*s report on the conclusions regarding the availability of water to meet this demand and the time at which it would be needed. WATER SUPPLY OF SAN DIEGO COUNTY WATER AUTHORITY The only hope for a water supply for the ultimate needs of the Carlsbad Municipal Water District is through importation by the Metropolitan District and the San Diego County Water Authority. Local sources are now fully developed and reliance must be placed on outside sources if use is to be expanded. This con- dition applies fully to the Carlsbad Municipal Water District and nearly com- pletely to other parts of San Diego County. 24 The most recent official expressions regarding the water needs and water supplies of San Dirgo County are the June 1955 report of R. S» Holmgren, General Manager and Chief Engineer of the San Diego County Water Authority and its review by the Board of Engineers consisting of Raymond A. Hill, John S. Longwell, and Carl R. Rankin, These reports cover the extent and use of the present water supplies with estimates of future needs and possible additional water that may be available to meet future demands. These reports represent a recent and official position of the San Diego County Water Authority. Whether there is agreement or disagreement with the results stated in these reporte, they represent a necessary starting point in any attempt to estimate the water supply which the Carlsbad Metropolitan Water District may secure in the future from the San Diego County Water Authority. It is axiomatic that the San Diego County Water Authority can only deliver to its member units the water which it is able to secure from the sources that may be available to it. The report by Mr. Holmgren and its review by the Board of Engineers are in general agreement in regard bo present conditions but differ in their estimates of future demands and supplies, The different sources of supply considered can be discussed separately. The following discussion of additional water supplies that may be secured by the Authority to meet County needs is in terms of total supply for total needs. It is assumed that the division of any such additional supply among member-units of the Authority would follow present practices for the division of existing sources of imported water. If such additional supplies are divided among the member units of the Authority on the basis of their preferential rights, units having low assessed values and large water needs would 25 not secure the required amount of water from their then preferential rights and would be dependent on securing excess supplies available to the older established units of the Authority which such older units did not require either temporarity or permanently,, Colorado River Supply When the San Diego County Water Authority joined the Metropolitan Water District it accepted the merger of San Diego's right in the water supply of the Colorado River with that of the Metropolitan Water District. This total supply is 1^212,000 acre feet per year at the Colorado River Intake. The priorities for diversion from the Colorado River agreed upon in 1930 between the seven California diversion interests included 1,100,000 acre feet per year for the Metropolitan Water District and 112,000 acre feet per year for San Diego. Under the merger of the Colorado River rights of the Metropolitan Water District and San Diego, the San Diego County Water Authority became subject to the same conditions of service from the Metropolitan Water District as its other member agencies. This included each year a preferential right of the San Diego County Water Authority to secure the same percentage of the total Metropolitan Water District supply as the percentage of total accumulated tax payments of the San Diego County Water Authority bears to the total accumulated tax payment of all Metropolitan Water District member agencies. The San Diego County Water Authority, under present Metropolitan Water District policies, has the saire character of preferential right in the supply of the Metropolitan Water District that member units of the San Diego County Water Authority have in its supply. This represents a policy which has been established by law and practice to the extent that it is now usually referred to as a right. 26 The Authority's preferential right in the Metropolitan Water District's Colorado 5,iver supply, when all member agencies are demanding their basic rights, is about 120,000 acre feet per year (Holmgren's June 1955 report, p 26). Until the mwmber agencies of the Metropolitan District may use their full entitlements, Metropolitan water in excess of 120,000 acre feet per year may be available to the Authority. Mr. Holmgren estimates that the full Metropolitan Colorado River the supply will not be in use by other/member agencies until 1975 and that the Authority can secure Metropolitan delivery in excess of its basic right until that time. By 1975 Mr. Holmgren estimates the Authority will need 420,000 acre feet per year of Metropolitan water. This is 3«5 times the preferential right of the Authority. If the Authority should be able to secure its estimated needs for Colorado River water from the Metropolitan District to 1970 (329,600 ac ft,, Table 1, Holmgren report) and then should be cut back to its basic right by 1975 the reduction would be 63«5$. The results in the preceding paragraph are for Colorado River water secured from the Metropolitan District. The estimated safe yield of the local sources of supply of 106,600 a.cre feet per year would also be in use. The total demand of the Authority in 1970, as estimated in the Holmgren report, is 436,200 acre feet which would increase to about 525,000 acre feet in 1975- If Metropolitan service should be reduced to the basic right in 1975, the Authority would have available then only 226,600 acre feet or 43$ of its forecast 1975 demand. If the Authority had received excess Metropolitan service to 1970 and then had to cut back to its basic right by 1975, the reduction in its 1970 use would be l*&%* These results indicate the position in which the Authority could be palced if it expanded its deliveries in accordance with the forecast in the Holmgren report based on using surplus Metropolitan service to 1970, and the Metropolitan District had no other source of sources of water supply by 1970 to 1975. 27 In the preceding discussion it has been assumed that a Colorado River supply of 1,212,000 acre feet per year will continue to be available for diversion by the Metropolitan Water Districto This assumption is discuased in the September 12, 1955 report to the San Diego County Water Authority by its Board of Engineers. This Board concludes that when extensive projects are contructed in the Upper Colorado River Basin and the requirements of the Mexican Treaty and other possible limitations are met, the Colorado River supply of the Metropolitan Water District may be red\iced to 570,000 acre feet or less than half of its right as now recognized. The Board concluded that this condition might occur by 1970. The Board urged that the San Diego County Water Authority take definite steps toward resolving these problems with the Metropolitan Water District before any action was started toward providing additional aqueduct capacity. The above conclusions of the Board of Engineers involve forecasts of uncertain future events. Should the conditions regarding the Colorado River supply considered by the Board be realized there would be no question regarding the seriousness of the effect on the Metropolitan W: ;,er District and all of its member agencies. At present th^re is divertible water in the Colorado River available to the Metropolitan >Tater District in excess of its 1,212,000 acre feet. This results from the present use in the Upper Basin of less than the 7,500,000 acre feet per year dafined in the Cororado River Compact. If and when Glen Canyon reservoir may be constructed, its initial operation will restrict deliveries to the Lower Basin to the Compact and Treaty obligations in order that this large storage may be filled as quickly as the available stream flow may permit. When such storage operations begin there may be some restrictions placed on California diversions. In view of pending litigation the final outcome, in my opinion, is not predictable. 28 Even if the Glen Canyon Reservoir should be authorized and its construction started in the near future, it would not become operative until about 1970. Reduction in the water supply obtainable by the Metropolitan Water District from the Colorado River in 1970 would accentuate the need at that time for an additional source such as the Feather River Project. As it is expected that a major additional supply will be needed by 1970 to 1975 even if all of the presently planned Colorado River supply remains available, the possibility that less Colorado River water may be obtainable emphasizes an existing need as well as increasing the amount of new water that may be required. Feather River Project Mr. Holmgren classifies the Feather River Project as the most hopeful source of additional water. The State Engineer reported on this project in February 1955• A review of this report, for a legislative committee, was completed on December 31» 1955 by the Ber-htel Corporation. The general plan for this project has now been outlined ivith sufficient definitaness so that the physical service it could supply can be applied to San Diego County. There remain alternate methods of conveyance to be determined but all alternates would furnish generally similar water supplies to the Southern California coastal area. It is proposed that the Feather River Project shall deliver 1,200,000 acre feet per year to the area of the Metropolitan Water District. This would represent a supply equal to that now considered to be available from the Colorado River. The program of the project as now proposed would provide for its delivery in about 1975. As yet there has been no recommended plan by the State Engineer for the parts of this supply to be used in separate parts of the Southern California service area. He proposed to sell this water wholesale at canal side form conduits built at State expense. On this basis the amount of water any local area 29 might secure would depend on the contract which that area might make with the State. The Metropolitan District has proposed that it purchase all of this supply and handle its delivery within its area. If direct purchases from the State should be made, the Authority might be able to acquire the use of the approximately 300,000 acre feet of additional water that Holmgren has estimated the Authority will need in 1975. This would be 25% of the total proposed Feather River supply to be delivered to Southern California. If the Feather River supply should be handled by the Metropolitan District and divided among its member agencies on the same basis now used for Colorado River water, the Authority's share might not exceed 10$ of the total similarly to its basic right in the Colorado River supply, This, with the Colorado River supply, would meet only $8% of Holmgren's estimated total need for outside water in 1975« The preceding discussion has been limited to the permanent water supply that the Authority might secure from the Feather River Project, if the project became a reality. The Authority might also secure increased service from the Feather River project in the early years of its operation until other member agencies desired to use their full allotments. Such use would create later problems in releasing the use °? such surplus supply when the full use of the Feather River water might be reached similar to those that will occur with the Colorado River supply if new sources are not available when such full use occurs. The preceding discussion also assumes that the Feather River Project will meet all of its many problems, other than water supply, and will be ready to deliver water to Southern California in 1975. Many are taking this assumption for granted and are working for an even earlier completion date. Prior to active construction on the project, agreement will need to be reached on many conflicting and controversial matters. State support for some $1,500,000,000 of general obligation bonds for the construction of the project will be needed if it is 30 built by the State. Before the people of the State can be expected to assume this financial load, they are entitled to know the general basis on which the water will be divided as between areas of origin and the principal areas of use, to have some adequate form of State agency created which can effectively construct and manage such a project and to have enforceable committments from the areas of service covering payment for water which they are to receive. While legally it may be possible for the voters of the State to obligate themselves for the financing of this project without these safeguards, it may be difficult to secure approval by the voters even with all reasonable precautions against increased State obligations which might result if the project does not fulfil its expe ctations. Another very active question that will need to be answered is whether the project will be built entirely by the State or jointly with the Federal Government. The U. S. Bureau of Reclaimation now has plans for the construction of the San Luis Project which would serve about half of the lands in the San Joaquin Valley which the State proposes to seive from its Feather River project. There can be no duplication of this service without failure of both projects. There is no necessary physical conflict between the two plans. The Bureau*s project would use some of the same water supply, would build a similar canal and would use about one—half of the capacity of the San Luis Reservoir site. Water supplies, reservoirs and canals have been jointly used in California without material difficulties ' and there are no physical reasons why such joint use could not be successfully accomplished in this project. A realistic meeting of this issue is also a prerequisite to project construction. These general project problems which have been discussed are outside of the question of the amount and time when Southern California may require water in excess of its presently available supplies. Being outside of these needs of Southern California, they cannot be controlled and their settlement expedited by 31 Southern California alone. Consequently any present forecast that can be made of the time when a Feather River or other project conveying water from northern to southern California may actually deliver water there is subject to major uncertainty. It is my opinion that the solution of these issues and the completion of the project in the next 20 years would represent a better than average achievement. Other Sources Mr. Holmgren also discusses the possibility of reclaiming sewage, importa- tion from the Imperial Valley and conversion of sea water. Sewage reclaimation is physically feasible and may be economically feasible. However, use in San Diego County is largely urban or suburban with the same sources being used for domestic purposes and irrigation. The prejudice against the use of reclaimed sewage for personal purposes has, to date, and probably will in the future restrict its use to limited amounts of agriculture or industrial purposes. Sewage reclaimation does not appear to offer, at best, more than a partial solu- tion to the water supply problems of the Authority or of the Carlsbad Municipal Water District. The importation from the Imperial Valley discussed in Mr. Holmgren's report would be based on a method of removal of salts that is, as yet, in the experimental stage for such large amounts to be treated. While San Diego County may have some geographical advantages over the general area of bhe Metropolitan District in the conveyance of water from the Imperial Valley, this source of supply may become competitive if it should also be sought by the Metropolitan District. The exchange discussed by Mr. Holmgren could also be operated from Parker Dam. Conversion of sea water may, at some time, become economically feasible. It would represent an unlimited supply for areas within an economic limit of 32 pumping and conveyance. As large scale conversion, tinder presently available methods, is not able to produce potable water at sea side at a competitive cost, it is not considered to offer a solution to any of the present problems of the Carlsbad Municipal Water District. Conclusions on Water Supply of the Authority From the preceding review of the Holmgren report, the report of the Board of Engineers and other information the writer has reached the following conclusions regarding the total water supply available to the Authority under conditions expected to exist for the next 15 years. The present water supply is limited to the physical capacity of the present two barrels of the San Diego County Water Authority Aqueduct of about 140,000 acre feet per year plus the supply available from local sources. While tBie local sources are estimated to have a mean annual safe yield of 106,600 acre feet, this safe yield is not now available. Past overdrafts on storage have depleted reservoir carryover and the yield of local supplies is now relatively small. This yield will not be restored until one or more years of above average run-off have occured. While such occurence is expected, ther is no basis on which the time before local run--off can supply the estimated safe yield can be forecast. Present deficiencies may extend beyond 1956. An estimate of the requirements for Colorado River Water of the San Diego County Water Authority for the year November 1, 1955 to October 31> 1956, dated November 4, 1955 has been made by the Authority. For an average wet winter the estimated total demand on the Metropolitan Water District was 109,000 acre feet. For a continuation of the present drought, it was estimated that the use of the full capacity of the present two barrels of 141,600 acre feet would have a shortage of 22,200 acre feet. To date the 1955-56 season has followed the 33 drought pattern and there is only a limited prospect that average conditions may be reached by the end of this season. In 1955 the City of San Diego released 16,000 acre feet of its share of the Aqueduct supply for use by other member units. As a result of its own depleted storage supply, San Diego has announced that only 7,500 to 10,000 acre feet will be released in 1956 unless substantial inflow to the City's reservoirs occurs during the reainder of the 1955-56 run-off season. Until .1970 the Authority cannot expect to have any source of water ex- cept the Colorado River supply which may be obtainable from the Metropolitan Water District. This may be limited to the entitlement of 112,000 acre feet per year or may be the 140,000 acre feet per year represented by the capacity of the present aqueduct until other Metropolitan Water District units use their full preferential rights. Conclusions 10, 11, and 12 of the Board of Engineers, in my opinion, express clearly and correctly the conditions relating to securing excess Colorado River water for use by the Authority. No dependence should be placed on securing permanently more than 112,000 acre feet per year. In view of these conditions and results it is concluded that the Carls- bad Municipal Water District should base its present plans on the amount of water it can expect to secure from the Authority from the supply obtainable by the Authority under its Colorado River entitlement plus some increase resulting from operating the present Authority aqueduct at capacity until use by the Metropolitan Water District equals the total Colorado River supply. After about 1970 the Authority can anticipate that its Colorado River supply may be reduced to its Colorado River entitlement. The Carlsbad Municipal Water District cannot rely on securing any water, in excess of that obtainable from the Colorado River supply, until the Metro- politan Water District or the State has committed itself to the source, amount, 34. and time at which it will have additional water available. Any such additional supply will have to be brought into the southern California area by some agency representing the area as a whole. A local unit, such as the Carlsbad Municipal Water District, cannot, by itself, iontrol the decisions and take the respon- sibilities that will be required before such additional outside waters can be secured. The Metropolitan Water District is the existing overall agency which should assume this responsibility. Until the Metropolitan Water District has a program on which reliance can be placed, the Carlsbad Municipal Water District should proceed on the basis of the water it can obtain from the present Colorado River supply of the Metropolitan Water District. PREFERENTIAL RIGHTS The preferential right of the Carlsbad Municipal Water District in 1953-54 was 1.21 percent. Applied to the completed capacity of the present Aqueduct of 215 sec ft this is 2.6 sec ft (8th Ann. Rep., Table l). Applied to a capacity of 195 sec ft it is 2.36 sec ft. The preferential right of the Eistrict in future years will depend on the relative increase in assessed value of the District and in the remainder of the Authority area. Additional annexations will tend to decrease Carlsbad's percentage. If water can be secured for undeveloped areas in the Carlsbad Municipal Water District, its increase in assessed value will be more rapid than in areas now more fully developed. A factor in the increase in assessed value in the Carlsbad Municipal Water District is the Encina steam plant of the San Diego Gas and Electric Com- pany on Agua Hedionda. The 1955 assessment on this plant was about equal to the assessment on all of the rest of the District. Further enlargement of this plant is planned. 35 In 1953-54 the Carlsbad Municipal Water District had an assessed value of $7.490,890 equal to 1.13$ of the total assessed value for the Authority area for that year. In 1955 the locally assessed property had a total assessed value of $7,593,750 and the state assessed property $3,513,120. The state assessed property is mainly the Encina steam plant. The locally assessed valuation increased by about 1«5$« The total assessed value with the steam plant increased 115$. Plate 10 of Holmgren's June 1955 report shows 750 million assessed value in 1955« On this basis the Carlsbad Municipal Water District would have an assessed value in 1955 of about two percent of the total for the Authority. For the I960 Holmgren estimates that the assessed value of the Authority will be 1900,000,000 (Plate 10) and Short estimates that for the Carlsbad Municipal Water District it will be $2S,Of0,000 (Plate VI). On this basis the assessed value for Carlsbad in I960 would be about three percent of the Authority total. For 1970, Holmgren estimates that the assessed value of the Authority will be $1,200,000,000 and Short forecasts that the assessed value of the Carlsbad Municipal Water District will be $49,000,000. On this basis Carlsbad would have about four percent of the total Authority assessed value. Short also esti- mates that the water demand of the Carlsbad Municipal Water District in 1970 will be about 12,700 acre feet. Unless this amount of supply for the Carlsbad Munici- pal Water District has been available for its use, development in the District will not create the assessed values which Mr. Short has forecast. The same conditionas apply to the increase in assessed value for the Authority as a whole but to a somewhat lesser extent. The preceding results represent an increase in the assessed value of the Carlsbad Municipal Water District of &1% for the five years 1955 to I960 and of 36 75$ for the 10 years I960 to 1970. The similar percentages of increase for the Authority would be 20% for 1955 to I960 and 33% for I960 to 1970. Such a rate of increase for the Carlsbad Municipal Water District would be over four times as great as that for the Authority as a whole for 1955 to I960 and over twice as great foe I960 to 1970. These ratios might be realized if the Carlsbad Municipal Water District has the water available over these years with which to create values as the older areas in the Authority have already reached a more nearly complete development. The actual increase in assessed value that may occur in the Carlsbad Municipal Water District by 1970 will be mainly controlled by the amount of water available for use in creating such values. Under the preferential right basis of dividing vater in the County Water Authority Act, Sec 5 (H)» the amount of water the Carlsbad Municipal Water District will be entitled to receive when the available total supply is fully used will be based on the accumulated past assessed values and resulting taxes. This places the District in the position where water is needed to develop assessed Tralue and assessed value is required to secura a dependable water supply. The statements can be resolved only under conditions where the Authority can furnish sufficient water to supply the demands of the units expanding their use of water in excess of the supply obtainable under their preferential rights. Such surplus service needs to be available until full development may have been reached in the unit. The then demand in the unit can then be met form the preferential right of the unit provided the total supply then available to the Authority is adequate to meet the then total demands. By 1970 present differences in past tax payments to the Authority will have been partially equalized and preferential rights will approach the percent- ages of the then assessed values. However, the preferential right of the 37 Carlsbad Municipal Water District will still be reduced by its low assessed value in the early years of the Authority. Giving consideration to all of these factors it is considered that the preferential right of the Carlsbad Municipal Water District by 1970 may not exceed three percent. A preferential right of three percent would make available to the Carlsbad Municipal Water District an Aqueduct supply of about 3500 acre feet per year from the Authority entitlement of 112,000 acre feet. About 4,200 acre feet would be available from the present Aqueduct capacity, provided that the Metropolitan*s Colorado River supply is not fully used by its other member agencies by 1970 and water in excess of its entitlement is available for use by the Authority. assessed values Using the estimated / - in 1970 of Mr. Short for the District and Mr. Holmgren for the Authority, the Carlsbad Municipal Water District might have a preferential right at that time as large as four percent. Such a right would enable the Carlsbad Municipal Water District to secure 4,700 to 5,600 acre feet per year respectively for the two conditions previously used for a three percent preferential right. Such a result would represent relatively favor- able conditions and would exceed the supply on which reliance can be placed. A Colorado River water supply in excess of its entitlement can be obtained by the Authority, even with a second aqueduct, only if the other member agencies of the Metropolitan Water District stand relatively still in their development while the Authority agencies increase their use relatively rapidly. This situation was pointed out and discussed in some detail by the Board of Engineers in their September 12, 1955 report. From all of these considerations it is concluded that, by 1970, the preferential right of the Carlsbad Municipal Water District in the Authority supply will probably not exceed three percent but that under more favorable and less probable conditions it might reach four percent. 38 SURPLUS SERVICE WITHIN THE SAN DIEGO COUNTY WATER AUTHORITY In 1955 the Metropolitan Water District was temporarily unable to meet all water demands of its member agencies as the installation of additional pumps had not been completed. It is expected that these pimps will be in operation by July 1956. Additional pumps will be needed before the Metropolitan Water District can divert its full entitlement from the Colorado River. It can be assumed with reasonable assurance that the continued installation of pumps and needed enlargement of its aqueduct will be completed by the Metropolitan Water District in advance of the need for the capacity which they will make available. It is considered that the Authority can rely on the Metropolitan Water District having facilities to divert and deliver its full entitlement from the Colorado River whenever a de:.and for its use develops among any of the member agencies of the Metropolitan Water District. Untila source of additional water and a time for its delivery may be assured, the only supply the Authority can obtain from a second aqueduct is a greater amount of the Colorado River supply which other member agencies in the Metropolitan WateA District may not use. Such unused water will be available only until demand in the Metropolitan Water District may equal the total supply. It is not considered that the Authority can secure additional Colorado River water by the construction of a second aqueduct sufficient in amount or available long enough in time to justify the Carlsbad Municipal Water District in basing its present plans on its use. Table 9 in the Eighth Annual Report of the Authority shows-ja total use of water in 1953-54 by the then units in the Authority of 137,901 acre feet. Table 8 shows 85,803 acre feet of local and 52,098 acre feet of Colorado River water was used. For normal run-off conditions the safe yield of local sources 39 of -units now in the Authority is estimated to be 98,600 acre feet. This with the Colorado River entitlement of 112,000 acre feet, gives the present Authority area a total supply of 210,000 acre feet per year. Such a supply would have an excess over the 1953-54 use of about ?0,000 acre feet or 51$ in execss of the use in 1953-54* The increase in total use for the five year period 1948-49 to 1953-54 was about one-half of this excess supply in 1953-54- However, it cannot be concluded from this result that the remaining available supply will meet Authority needs for the next 10 years as the past increase in use does not reflect the effects of recent annexations. Mr. Holmgren estimates that the full safe yield of local supplies plus 137,200 acre feet of Colorado River water will be required in 1959 (Table l). The Board of Engineers does not make a specific estimate of the Autnority use in 1959 but considers generally that Mr Holmgren's estimate represents too rapid a rate of increase in use. In his June 1955 report (Table 1), Mr. Holmgren estimates that the total requirement of the Authority units in 1959 will be 235*800 acre feet. If local sources can supply water equal to their estimated safe yield in 1959 of 98,600 acre feet, the present aqueduct capacity will just be able to supply the remainder of this demand. Whether this condition occurs in 1959 or later, when it does occur it means that water in excess of their preferential rights will be obtain- able by any Authority unit only to the extent that some other units in the Authority may not use their full preferential supply. The Authority unit having the largest use and preferential right is San Diego, In 1946, for the then area of the Authority, San Diego's preferential right was 85,42$. In 1954 it had decreased to 72.37$ mainly as a result of the annexa- tions to the Authority, By the time the present Colorado River supply is fully used, San Diego's preferential right may be less than 70$. On this basis San Diego would be entitled, under its preferential right, to about 96,500 acre feet of the Aqueduct capacity. San Diego would also have available the supply from its local sources having an estimated long time mean safe yield of 46,00 ac ft 40 per year. In Table 1 Holmgren estimates that San Diego's total demand in 1959 will be 103,000 acre feet. If in 1959 its local supplies should yield 46,000 acre feet, San Diego could release 39*500 acre feet of the aqueduct capacity to other unist. This would enable all of the other present Authority units to secure about twice their preferential right in 1959. To such extent as the local sources of San Diego may still be depleted in 1959 and unable to provide their estimated mean annusl safe yield, this excess supply for other units would be proportionately reduced. Some other units might not require their full prefer- ential right in 1959 but no other unit has a sufficiently large preferential right for the release of any part of it to be a material aid to the units of large demand in proportion to their preferential right. These comparisons indicate that if local run-off is back to normal or above by 1959> The Carlsbad Municipal Water District might secure about twice its preferential right through release from San Diego. This would be the maximum surplus that can be anticipated in 1959. For I960 Holmgren estimates an increase in demand of 15,100 acre feet for the present Authority units with only 1,000 acre feet of this increase occur- ring in San Diego. A similar computation to that made for 1959 indicates that San Diego might release 38,500 acre feet in I960 which would enable all other units to receive nearly twice their preferential rights. Such an excess would just be sufficient to enable them to meet Holmgren's estimate of their I960 demands, provided also that the yield of their own local sources of supply is equal to their long time safe yield. To such extent as the local supplies in I960 may be less than their estimated total safe yield there will bw a shortage in meeting Holmgren's estimated I960 demand. Holmgren does not show estimated demands on the Aqueduct for individual years from I960 to 1970 in his Table 1. For 1970 he derives a total demand for la Colorado River Water of 268,800 acre feet for the present Authority units with 60,800 acre feet additional for unorganized areas that may be annexed and served by that time. For 1970 the estimated Aqueduct demand of San Diego is 85,000 acre feet. This represents 16% of the Colorado River entitlement of 112,100acre feet. As San Diego's present preferential right is less than 16% and is de- creasing, San Diego will need more than the supply available from the Authority's Colorado River entitlement. If increase in use should be less rapid than that estimated by Holmgren, the conditions illustrated above would be deferred until some year after 1970 but would be reached whenever there may be full use by the Authority of its Colorado River entitlement* * If, by 1970, the Metropolitan Water District, as a whole, is not using its t full Colorado River supply and the Authority can secure water equal to the capacity, of the present two barrels of its Aqueduct there would be about 25,000 acre feet greater supply available to the Authority than those used in the preceding illus- tration. This increase represents about 12.% of the total of the safe yield of the local supplies plus the Authority's Colorado River entilemente Mr. H olm«- gren's Plate 2 scales to indicate an estimated increase in use of about 18,000 acre feet per year for the period 1970 to 1975. Using this rate of increase, the difference between the Colorado River entitlement and the present Aqueduct capacity would defer the time when demand equaled the supply by less than two yearsj using the more conservative conclusions of the Board of Engineers this time might be 3 or h jiears. In either case the deferment of the time when demand may meet the capacity would be relatively short, These comparisons indicate that the Carlsbad Municipal Water District cannot anticipate being able to secure additional water from the Authority in .excess of its preferential right after use by other Authority units increases to equal the total Authority entitlement in the Colorado River supply of the U2 Metropolitan Water District with perhaps some additional time when other Metro- politan Water District agencies are not using their full rights. The deliveries may need to be restricted to the entitlement of the Authority by 1970 to 1975. SUMMARY OF WATER SUPPLY OBTAINABLE BY THE CARLSBAD MUNICIPAL WATER DISTRICT FROM THE COLORADO RIVER SUPPLY OF THE AUTHORITY The preceding discussion of the Colorado River supply of the Metropolitan and the Authority which Carlsbad Municipal Water District may secure from the Authority at different times and under different assumptions may be summarized as follows Acre feet per year 1. Use of 195U preferential right applied to present Aqueduct capacity 1,670 2, Estimated yield of I960 preferential right of 2.0$ with no release by other units of the Authority 2,760 3» Estimated supply in I960 if San Diego*s demand follows H olmgren's Table 1 and local supplies furnish their mean safe yield 5,500 4. Estimated supply in 1S70 with the Authority limited 112,000 ac ft, the increase in Authority demand Predicted by Holmgren in Table 1, normal yield of local supplies, and no releases of any of its preference rights by San Diego A — For a 1970 preferential right of the Carlsbad Municipal Water District of Jfc 3,500 B — For a more favorable and less probable 1970 preferential right of the Carlsbad Municipal Water District of h% U,500 5» Same as U except Metropolitan Water District water available to full capacity of present Authority AqueeEuct & ~ For a 1970 preferential right of the Carls- bad Municipal Water District of 3% li,200 B - For a more favorable and less probable 1970 preferential right of the Carlsbad Muni- cipal Water District of k% 5j600 6. For the period I960 to 1970, for normal local water supplies, the water obtainable by the Carlsbad Municipal Water District may be expected to vary between the estimates for I960 and for 1970, The preceding results indicate that with the present Authority Aque- duct the Carlsbad Municipal Water District may anticipate being able to secure 3,000 to 5,$00 acre feet of aqueduct supply in I960, the difference in these amounts depending on the extent to which San Diego may release its preferential supply. By 1970 the preferential right of the Carlsbad Municipal Water District may have increased so that it can reasonably expect to secure 3,500 to U,200 acre feet per year from this right, the difference depending on whether the Authority is then limited to its Colorado River entitlement or whether it can secure water to operate the aqueduct at capacity. The supply that may be obtainable under more favorable but less probable conditions may be one-third greater than these amounts. The above results are b sed on the assumption that the rate of increase in use in the other undeveloped units of the Authority will proceed at a similar rate of increase and reach full use of their preferential right at a similar time as the Carlsbad Municipal Water District. This is a reasonable assumption. Actual increase in the total use may be acdelerated if more areas are annexed and undertake to increase their use of water. It is concluded that the Carlsbad Municipal Water District cannot rely on securing a permanent water supply from the Colorado River entitlement of the Authority of more than U,000 acre feet per year. Somewhat larger deliveries may be secured until the Colorado River supply of the Metropolitan Water Bis- trict is fully used by its member agencies and until the Authority supply is fully used within &he Authority area. Such complete use of the Colorado River supply is expected to occur from 1970 to 1975. ill* It is concluded that the Carlsbad Municipal Water District may be able to secure only temporary use of pipe line capacity from the Authority Aqueduct in excess of U,000 acre feet per year until t-ie Metropolitan Water District or other agency delivers water from some additional source into the southern Cali- fornia Coastal area. It has also been concluded that such delivery of additional water cannot be expected before 1970. LOCAL WATER SUPPLY OF CARLSBAD MUNICIPAL WATER DISTRICT The local water supplies available for use within the Carlsbad Municipal Water District which require consideration in this report are: (1) Ground water from the Mission Basin on the San Luis Rey, (2) a limited amount of local ground water within the District, (3) local run-off storable under permit in Calavera Reservoir, and (it) sewage reclamation. There are no other sources of undeveloped local water which are available to the Carlsbad Municipal Water District. Ground water within the service area of the District is limited in amount, difficult to secure, and insufficient in quantity to furnish a material part of the ultimate needr of the District, Mr. Short in his June 195£ report lists the Terramar Water Company as having wells supplying U5>0 acre feet per year. The Carlsbad Mutual Water Company has a well of limited capacity near Calavera Reservoir. While the water obtained from these wells is valuable to the areas now using it, the ground water that may be obtainable within the area of the Dis- trict does not represent a source of material amount in relation to the overall District needs. Storage of local run-off may be useful when it is available but is also too sn®Q.l in amount and uncertain in occurrence to be a reliable source of sup- ply. Any local run-off into Calavera Reservoir is a by-product of the use of the reservoir for other purposes. us Mr. Short lists treated sewage effluent and other sources as 50 acre feet per year based on his field observations. Reclaimed sewage is a reuse of some other source of supply. Reuse of sewage within the Carlsbad Municipal Water District, at most, can only increase the use of water originating in some other source. Where local supplies can meet only a fraction of the total ulti* mate demand, reclamation of sewage from such use can supply only a small part of the remaining need. No projects have been proposed for reblaimiing the sewage from the larger urban areas in San Diego County and conveying it for use in the Carlsbad Municipal Water District. The preceding discussion leaves only the ground water from the Mission Basin for further discussion* MISSION BASIN SUPPLY The Carlsbad Mutual Water Company has established rights to pump from the ground water of Mission Basin. These rights enable this company to pump from this source but they also include restrictions on the amounts pumped and the area within which such water may be used. No material expansion over past use can be expected. The questions relating to this souEce of supply re- late mainly to whether the source can supply the amount of water which the Mutual Company is entitled to take. The legal right to take is considered to be established? the water available to be taken needs tn be considered. The best measure of the extent of this supply is the record of past diversion. The draft on the Mission Basin wells be the Carlsbad Mutual Water Com- pany, as shown from 1930 to 19U? on a diagram prepared by Mr. S. D. Fraser, formerly manager, and from 19U7 to 195U in the February 1955> report of Mr. C. R. Browning, consulting engineer, gives the following results. Mean Annaul Amount of Water Pumped in acre feet 5 years - 1925-29 1,6U6 10 years - 1930-39 1*930 7 years - 19UO-k6 2,232 3 years - 19U7-U9 3,U26 5 years - 1950-51* 2,i|6l 30 years - 1925-5U 2,192 Mr. Fraser's results are stated to be water metered plus 15$. It is understood that this represents deliveries plus 15$ transmission loss. Mr. Browning's results are stated to be water produced which is understood to re~ present water measured at the wells. For 19U8 and 19U9 the results on Mr. Fraser's diagram and Mr. Browning's are in close agreement. These records show a substantial increase in draft in 19U7 to 19U9. The moving out of military population is stated to have been the cause of the reduction in use since 19U9« Aqueduct water was not obtained until 195U and the amount in 195U was insufficient to affect the draft on these wells. The Mutual Company is limited to a draft of 200 miners inches or four seccmd feet. The use of this water is limited to a defined area extending two miles inland from the ocean shore and to Agua Hedionda on the south. The City of Carlsbad includes about 5*000 acres of which from 2,000 to 2,200 acres are stated to be fully urbanized. There are about UOO acres irrigated. Mr. Dennis Wood, Manager of the Mutual Company, estimated that present use Ls 2,200 to 2,500 acre feet per year. Of this use about 350 acre feet is in the North Carlsbad area which is considering annexation to Oceanside. In his June 1955 report, Mr. Short has estimated the present water sup- ply from these wells to be 2,775 acre feet per year based on a 7-year average shown by the records of the Carlsbad Mutual Water Company* This supply would hi represent operation at the rate of draft of four second feet for 97 percent of the time. This yield is considered to be as large as can be obtained by the Carlsbad Mutual Water Company under Its k sec ft limitation* It aay be larger than can be sustained under present conditions of use by the Carlsbad Mutual others Water Company and/without inducing salt water intrusion. The run-off of the upper drainage area of the San Luis Rey River is stored in Lake Henshaw. This reservoir has a capacity of 19h,300 acre feet and has never been completely filled since its completion in 1923. Inflow from lower tributaries provides irregular run-off in the lower portion of the river and is a source of ground water recharge in the Bonsall and Mission Basins, Some investigations of the Mission Basin have been made by the State Division of Water Resources. A report for presentation to the State Water Resources Board on January 19,1953 discussed a proposed experimental surface barrier project at the San Luis Rey River Valley N arrows to prevent salt water intrusion. It was reported that for the three years, 19^9 to 1951, surface inflow was negligible in amount. With a total export of 15,80£E acre feet during these three years, the ground water lowered an average of 17 feet. The effective area of the Mission Basin is 2,800 acres. Using an expected specific yield of 15$ these results indicate a reduction in ground water storage of 7,200 acre feet leaving 8,600 acre feet or 2,800 acre feet per year to be sup- plied from lateral inflow or from movement from the Bonsall Basin, The Divi- sion concouded that the then draft would need to be reduced by 1,200 acre feet to maintain the ground water above sea level. From 19U6-l|.7 through 1950-51 the ground water at a well two miles from the ocean lowered from plus 23 feet to minus 15 feet. In another report dated November 6,1952 the Division found the saline front was then between 3,700 to 7,800 feet from the ocean. The San Luis Rey U8 N arrows are 600 to 1,100 feet wide and extend two miles inland. This report lists about 200 wells of all types in the Mission Basing many of them were no longer in use. Much of the Mission Basin has a mudcap over the main aquifer* The base of this mudcap is at a depth of about 150 feet; it may not be con- tinuous under the Basin, In 1936 the Division of Water Resources reported that a dam creating a reservoir at the Bonsall site having a storage capacity of 162,610 acre feet could be built at an estimated cost of $5,316,000. In its January 9>1953 report the Division estimated that the present cost of such storage would be $13*300,000 with a safe yield of new water of 10,000 acre feet per year. This represents an annual cost of $60 per acre foot of such yield. Based on these results this storage project does not appear to be attractive for use in regulating the available run-off of San Luis Rey River. Such a reservoir would also be usable for storage of Aqueduct watere Hot-rever, it is at a relatively low elevation, is off-center from the areas of major de- mand, and the proposed size and cost appears to be excessive fot the extent of use that could be obtained in regulating an Aqueduct supply. There has been discussion of the formation of a water replenishment district to acquire and spread water in the Mission Basin and pending litigation is understood to have been suspended while such an organization is being con- sidered. An act providing for such water replenishment districts was passed in 19-55 and one such district is now operating in Orange County, Such a dis- trict might include replenishment of both the Bonsall and Mission Basins or be limited to the Mission Basin only. The direct interest of the Carlsbad Muni- cipal Water District would be limited to replenishment in the Mission Basin, U9 Such replenishment in the lower portion of the Mission Basin would main- tain higher ground water elevations and assist in preventing salt water in- trusion. Recharge from San Luis Rey run-off would not be materially changed unless surface storage was available to regulate flood flows to rates which would be absorbed. Recharge water for Carlsbad would need to be delivered in the vicinity of the Carlsbad wells if the recharge is to be available for Carls- bad use. Recharge of the lower Mission Basin with purchased Authority water would be subject to the same present limitations on delivery capacity that affect de- liveries for direct use. Delivery through the Fallbrook-Oceanside branch would be limited to its capacity in excess of direct use demands. Delivery further upstream would be subject to absorption before reaching the Carlsbad wells and to draft by upper users before natural percolation down stream would occur. The absorption that could be secured in the vicinity of the Carlsbad wells may be restricted by the presence of the mudcap overlying the deeper material. Such recharge, to be effective, would require lowering the ground water during periods of deficient supply so that storage space is available when surplus water is available. The depth of guound fluctuation that can be used, without inducing salt water intrusion, is limited. The ground water storage available above sea level is also limited. In view of all of these conditions the ground water replenishment with purchased Authority water in the Mission Basin does not appear to represent a probable solution to the water supply needs of the Carlsbad area. There are problems relating to the use of the naturally available water supply of Mission Basin for whose solution the presently available information is inadequate. The Carlsbad Mutual Water Company and the Carlsbad Municipal Water district should both participate in any cooperative efforts to secure the information 50 needed for an equitable solution of such local problems and be guided in their later actions by the results secured. Litigation among the climants to the use of the ground water of Mission Basin will not make available any more water or reduce the danger of salt water intrusion. The information available regarding the ground water supply of Mission Basin is considered to support the following conclusions. 1 - The present draft on the Basin by all users equals and probably exceeds its safe yield from its natural sources of supply, 2 - There is uncertainty whether the present draft can be sustained without salt water intrusion resulting in deterioation of the water in the lower portion of the valley. 3 - At least until years of large run-off which replenish the Basin may occur draft should be limited to present necessities, k - The Mission Basin does not represent a source from which any increased draft from its natural recharge can be obtained by the Carlsbad Mutual Water Company, $ «• The limited depth of ground water storage, uncertainties regarding the ex- tent to which the mudcap may restrict recharge oS i?he main aquifer, the difficulty of controlling draft from artificial recharge, the high cost of pur- chased recharge water and the complications involved in the creation and opera- tion of a ground water replenishment district, make the Mission Basin unat- tractive as a prospective source of additional water supply for the Carlsbad Municipal Water District, 6 - The Carlsbad Mutual Water Company should preserve its rights in the ground water of Mission Basin and operate its wells to secure its full entitlement from the Basin. 51 7 — The Mutual Water Company and the Municipal District should participate in all investigations and activities relating to Mission Basin and be guided in their later decisions by the then results and conditions. Should a water re- plenishment district be proposed it is recommended on the basis of present in- formation, that the Carlsbad area should oppose a district sufficiently large to include both the Bonsall and Mission Basins. The Carlsbad area should also oppose inclusion in a Mission Basin water replenishment district unless means are found for the Carlsbad area to have a voice in the activities of such a dis- trict proportional to its use of the benefits and the payments of its cost. 8 - In the water supply plane of the Carlsbad Municipal Water District the available supply of the Carlsbad Mutual Water Company from the Mission Basin should not be considered to exceed 2,500 acre feet per year of sustained yield, SUMMARY OF TOTAL WATER SUPPLY OF CARLSBAD MUNICIPAL WATER DISTRICT The several sources of water supply available to the Carlsbad Municipal Water District have been discussed. The results can be summarized as follows; Mean Annual Supply Acre feet Probable More Favorable but Water Supply Results Less probable Results From Mission Basin 2,200 2,500 Wells within the District 300 500 *n 1970 - From Colorado River entitle- ment of the Authority 3,500 U,500 In 1970 - From use of Authority Aque- duct to capacity U^OO 5,600 Totals in 1970 From Colorado River Entitlement 6,000 7,500 From use of Aqueduct Capacity 6,700 8^600 52 This estimated dependable supply from the Aqueduct from the Colorado River entitlement represents about one-sixth of the estimated ultimate requirements of the Carlsbad Municipal Water District. With the present local sources^ the dependabel total supply is about 25$ of the ultimate need. Even for the more favorable but less probable results the available supply represents only from 31 to 36$ of the ultimate District's requirement. Only these percentages of the devlopment of the District can be expected to be permanently served un- less an additional source of water supply is imported into southern California. These results indicate that the Carlsbad Municipal Water District has a water supply from its local sources and the Authority, based on its entitlement from the Colorado River, of from 6,000 acre feet per year to possibly 7,500 acre feet per year. Any increase in these deliveries that might result from the construction of a second aqueduct would be temporary uiftless the Metropoli- tan Water District secures additional water from some other source which is ready for delivery at the time when all of the Metropolitan Water District's entitlement from the Colorado River may be fully used. The time when the Metropolitan Water District's entitlement from the Colorado River may be fully used has generally been estimated as from 1970 to 1975* The time at which a project delivering water from an additional source may be completed and deliver such water is not subject to present determination due to the many complications and uncertainties involved. Such delivery cannot be expected before 1970 and its accomplishment by 1975, in my opinion, repre- sents a more probable date. The Carlsbad Municipal Water District, in my opinion, should not, at this time, undertake development in excess of that which aan be supported by the water supply available to the District from its local sources and that obtainable 53 from the Authority's share of the present Metropolitan Water District's Colosrado entitlement. Such sources represent from one-fourth to one-third of the esti- mated ultimate water requirements of the Carlsbad Municipal Water District. This condition should be recognized and District plans should be based on the avail- ability of such a limited supply. The only source from which a permanent additional supply may be obtained is by additional importation of water from new sources. Such importation of water from new sources can be expected at sometime in the future but cannot be relied upon in time to justify undertaking present development whose maintenance will depend on close timing between the exhaustion of the supplies now available and the arrival of some new source of supply. Development in excess of that which can be supported by local sources and the Authority's Colorado River en- titlement, in my opinion, should not be undertaken until a project for bringing in additional water is a reality with a time schedule on which reliance can be placed. It is my opinion, that no project now being discussed for supplying additional water, including the Feather River Project, meets the above requirement* WATER REQUIREMENTS The Carlsbad Municipal Water District includes a gross area of 21,000 acres. Of this area about 5,000 acres are in the City of Carlsbad of which about 2,000 acres now use water. In the June 1955 report to the District of the Boyle Engineering, Mr. Short estimated the ultimate water requirement of the District would be 2U,000 acre feet per year and that this use would be reached by the year 2000» The demand (Plate VIII) in 1955 was shown as about 3,300 acre feet increasing to 7,000 acre feet in I960 and 12,500 acre feet in 1970, By 1975, when past forecasts h ave generally predicted that all of the Colorado River supply of the Metro- politan Water District will be in use, the estimated demand of the Carlsbad Municipal Water District would be 15*000 acre feet. In Table Ictf Holmgren's report of June 1955 the gross area of the Carls- bad Municipal Water District is listed as 20,000 acres and its ultimate water requirement as 26,,000 acre feet. The local safe yield was estimated as 1,700 acre feet per year. The annual requirement from local and Colorado River sources was shown as 3*200 acre feet in 1955, 8,200 acre feet in I960 and 16,700 in 1970, These two estimates of ultimate requirements are in agreement within the ran&e of variation that is inherent in efforts to predict future use of water. H olmgren forecasts a use by 1970 that is one-third greater than that of Short. It is probable that the rate of increasein use in the Carlsbad Munici- pal Water District will be governed more largely by the availability of water than by the growth that might occur with an unrestricted water supply. In my opinion, use by the Carlsbad Municipal Water District in 1970 will be controlled by the amount of water then obtainable from the Authority. Mr. Short'e estimate of ultimate water requirements consists of 9>000 acre feet of urban and industrial use and 15*000 acre feet of irrigation. If the supply required for both of these uses should not be available to meet the expected rate of growth in demand, the irrigation use will be restricted before the urtoan use is limited. The Municipal Water District Act provides for a prefer- ance to domestic use at times of shortage. Mr. Short'B estimate included 11,050 acre feet per year for citrus and avocados and 3,950 acre feet for annual crops. CONNECTION TO KiLLBROOK*OCEANSIDE BRANCH The San Diego County Water Authority constructed a branch line to serve Fallbrook and Oceanside at the time the first barrel of the Aqueduct was built. This branch was constructed with Authority funds secured from the original bond issue. It has been used by Fallbrook and Oceanside for delivery adjacent to their areas. Since the Carlsbad Municipal Hater District was annexed to the Authority, it has conveyed the water supply it has received from the Authority through this branch by using the pipe line of Oceanside for conveyance from the branch to the Carlsbad Mutual Water Company system. Such conveyance has been made under agreement with the City of Oceanside and has been limited to the use of the part of the capacity of the Oceanside line not in use by Oceanside, As the use by Oceanside has been increasing, it has been unwilling to make long time agreements for joint use. The Carlsbad Municipal Water District is now operating under an agreement which will expire on June 30, 1956. Oceanside has offered to extend this joint use agreement to December 31» 3L956 subject to specified conditions. An agreement for such an extension is now being completed. For the purposes of this report it has been assumed that the Carlsbad Municipal Water District will have partial use of the Oceanside line until December 31* 1956 and that such use will enable the District to meet its present necessities until that time. This extension in time is a vital factor in any plans of the Carlsbad Municipal Mater District as it enables the procedure for financing and the construction of an ultimate connection to the Aqueduct to be completed before the agreement for joint use of the Oceanside line expires. The surplus capacity in the Oceanside line is not sufficient to enable the Carlsbad Municipal Water District to secure its full preferential supply from the Aqueduct at times of peak demand by Oceanside. Some other solution for conveyance of Carlsbad Aqueduct supply is urgently needed. It is the policy of the San Diego County Water Authority that each member unit taking water from an Authority branch line is entitled to use the same proportion of the capacity of that branch that its preferential right bears to the total preferential rights of all users of that branch. Fallbrook, 56 Oceanside, and Garlsbad would be entitled to use the Fallbrook-Oceanside branch on the following basis. Percent of Preferential Right in 195U Fallbrook Oceans ide Carlsbad 0.7U 2*23 1.21 Percent of Total Capacity 17.7 53.U 28.9 Percent of Capacity below Fallbrook 65 35 100 Based on 1955-56 assessed values, Carlsbad would be entitled to use of the capacity below Fallbrook* The capacity of the Fallbrook-Oceanside branch is reported to be 11 sec ft in its upper portions and 6 sec ft below the Fallbrook takeout. On the basis of the 195U preferential rights, Carlsbad is entitled to the use of 3,2 sec ft of the upper capacity and 2*1 sec ft of the capacity below the Fall- brook takeout. The capacity of the present two barrels of the Aqueduct is generally stated to be 195 sec ft. For this capacity the 195U preferential right of Carls- bad of 1.21$ in the present Aqueduct would be equivalent to 2.36 sec ft. Carls- bad's entitlement in the use of the lower part of the Fallbrook-Oceanside branch would enable it to convey about 905? of its 195U Aqueduct entitlement through the branch. As the assessed value of the Carlsbad Municipal Water District is in- creasing at a more rapid rate than that of Oceanside, Carlsbad's share in the rapacity of the Fallbrook-Oceanside branch will tend to increase in the coming years. The above results would be applicable when both Oceanside and Carlsbad were seeking to take their full preferential right through the lallbrook- Oceanside branch. At times when Oceanside's demand might be less than its 57 preferential right, Carlsbad could use the Fallbrook-Oceanside branch to convey additional water which might be obtainable from the Aqueduct, The attorney for the Sam Diego City Water Authority advised it that any member unit was entitled to have a connection to any Authority conduit. Acting on the request of the Carlsbad Municipal Water District, the Board of the Author- ity has approved a turnout from the Fallbrook»0ceanside branch for use by the Carlsbad Municipal Water District. It is the policy of the Authority to meet the cost of approved turnouts from their conduits- As a result of this action the Carlsbad Municipal Water District can connect to the Fallbrook-Oceanside branch. This makes available this method of securing Aqueduct water if it should be found that the use of such a connection represents the best method of secur- ing such water. A pipe line from the end of the Fallbrook-Oceanside branch to Reservoir No. 1 of the Carlsbad Mutual Wa-,er Company would enable Aqueduct water to be delivered to the Carlsbad Municipal Water District from Authority conduits without using the pipe line of Ooeanside. If built by the Carlsbad Municipal Water District, such a connection to the Fallbrook-Oceanside branch would meet the immediate needs of the developed areas in the Carlsbad Municipal Water Dis- trict but would not provide water for expansion in use. Such a line can be built in a relatively short time and its cost would be within the possible borrowing capacity of the District for short time loaB»» If no other plan for delivering the Aqueduct supply which may be avail- able to the Carlsbad Municipal Water District can be agreed upon and constructed within the remaining time that present use of the Oceanside line can be continued, a direct connection to the Fallbrook-Oceanside branch represent a possible means for meeting present needs. Such a connection would only be a temporary solution for Carlsbad's needs. The supply obtainable by this means would enable present development to be sustained but would provide for little if any increase in use. It should be retained as such a possibility in the District's planning but should be regarded as a "stop Gap" remedy to be used only if other programs should be found to be unavailable, ALTERNATE ROUTES FOR CONDUITS TO AQUEDUCT The present two barrels of the San Diego Aqueduct are about nine miles from the nearest point of distribution within the Carlsbad Municipal Water Dis- trict by the shortest route. Nc direct service from the Aqueduct can be secured with any shorter route except the limited service obtainable by a connection to the Fallbrook-Oceanside Branch. Mr. Short has investigated and made capacity and cost estimates for three routes from the Aqueduct to the District, For these routes local discussions to date have used the terms Red, Graen and Black. These names are taken from the colors ased for these lines on the maps showing their location. The Red line is the most southerly and follows generally the route of the San Marcos Branch dis- cussed in Mr. Holmgren's June 15^55 report, The Green line would leave the Aque- duct about seven miles north of the takeout of the Red line, pass through the hills and enter the northern boundary of the Carlsbad Municipal Water District. The Black line would divert somewhat north of the Green line, pass through local valleys to the valley of San Luis Rey and then turn soutwest along the alinement of the Green line to enter the Carlsbad Municipal Wayer District at the same location as the Green line. In any comparison of these three lines it is necessary to reduce them to common results. Some point within the District needs to be selected t:> which the delivery by each line would give equal service. Two such points have been 59 used in past comparisons. One is the so-called Point D from which branches would convey water to the northern and southern parts of the District, point D is located east of Terramar at an elevation which would provide grade for such dis- tribution t© the coastal portion of the District. The second point is Mt, Kelly located easterly of Carlsbad at a similar elevation. Roughly one-half of the District lies easterly from these two distribution points. If Point D (also known as Corillo's Corner) is used for comparison of the three' lines, then the Green and Black lines would need to be extended from Mt. Kelly to Point D. Similarly if Mt. Kelly is selected for comparison, the Red line would need to extend from Point D to Mt. Kelly,, Mr. Short has segregated his estimates so that any of these comparisons can be made. Mr. Short has also prepared estimates for each of the three lines for five capacities varying from 900 to 17,000 acre feet per year. In these cost estimates Mr* Short increased his unit prices for pipe approximately 10% over those used in his report of J une 1955. The results of these cos^ comparisons can best be shown by the summary prepared by Mr. Short. 6o Summary of Alternate Routes for Delivery of Water to Carlsbad Municipal Water District Water MMn Capacity cfs U7.0 33,1 23.8 5.0 2.5 Water Demand ac ft - 1 yr 17 ,000 12,000 8,600 1,800 900 Total Estimated Cost of Alternate Routes to Mt. Kelly Red $l,82lij,700 : 1,568,900 1,336,000 701,500 583,800 Green &l»9l4.9, 50O 1,711,600 1,5U3»100 931,600 821,200 Black 02,108,600 1,750^00 1,617,800 878,600 72U,800 Total Estimated Cost of Pipelines Between Mt. Kelly and Point D 17,000 § 286,700 $ 505,600 $ 505,600 12,000 238,900 105,200 1*35,200 8,600 22U,200 39U,700 39U,700 1,800 160,700 153,600 153,600 900 1U1,600 137,600 137,600 Delivery to Mt. Kelly is the most unfavorable comparison for the Red line, Mr. Short's estimates how the Red line has the lowest cost for all capacities for this delivery. For delivery to Point D the cost of the pipe line from Kt* -felly to Toint D should be added to the costs to Mt. Kelly for the Green line and Black line to get comparable results for delivery to Point D» The Red line delivers to Point D on its route to Mt. Kelly* These results show that the Red line has the lowest estimated cost. Its location is also the most favorable for joint use with other units along its route and for delivery to and draft from Meadowlark Reservoir if it should be built* The writer was requested to review the District's engineering with ad- ditional local work, if needed, to be done by the District's engineer. In accordance with this program, Mr. Short amplified the estimates he had made for 61•«., his J une 195>5 report at the writer's request. The writer was taken over these alternate routes by Mr. Bond and secured a general idea of the relative cond- tions to be encountered. Mr. Short states in his letter to the writer of January 16, 19^6 that - "In making tip the estimates for the respective pipe lines due consideration was given to the probable difficulty of construction. The Green Line Location would encounter some five miles of extremely difficult construction and the estimates reflect that condition," The detail cost estimates furnished by Mr. Short for each line furnish the following additional results. Red Green Black For Delivery of 17,000 ac ft, year Diameter of Main Line - inches 30 and 32 28 and 30 30 and 32 Length of Main Lina to Mt. Kelly - ft 62,300 86,000 102,000 Total Estimated Direct Cost of Main Line 1560^200 01,1106,100 $1,61*8,2.00 Estimated Average Cost of Main Line . . per lin»ft. &l£4i5 &E6..30 816.15 The increase in estimated cost per lin.ft for the Green line over the Red liae is about 6% and, in my opinion,, is fully justified by the conditions along this* route. The main difference in the estimated cost of the three lines is the re- sult of their differences in length. The above costs are exclusive of the costs of valves and structures, rights of way, and 20$ for contingencies. The esti- mate for the Red line includes $90,000 for a 3,000,000 gallon reseroir; a simi- lar item was not included for the Green and Black lines. The estimates for these three lines which Mr. Short has prepared are considered to be adequate to enable conclusions to be drawn and to fairly present the conditions for each line. Some suggestions could be made that the estimate for the Red line is unfavorable to that line. As all lines will need to provide 62 service to both Mt. Kelly and point D or their equivalents, the comparison of costs is even more favorable to the Red line than the results in the upper por- tion of the preceding table. Based on the preceding results and discussion it is concluded that any line from the Aqueduct for use by the Carlsbad Municipal Water District should follow the location of the Red line. While the estimates which have been made are adequate for use in selecting the location of such a line, final estimates should be based on field surveys and sufficient borings to reveal the conditions to be encountered in construction, Mr. Short has also considered the use of a conduit on the Red line to deliver water into the San Marcos Reseroir site, with a pipe line from the dam into the southern end of the Carlsbad Municipal Water District. He used 18, 16, and li; inch diameter pipe to convey water to the coastal strip south of Agua Hedionda. The 18 inch line had a capacity of 9«3 sec ft. If Meadowlark Reser- voir should be constructed such a line could provide well regulated service to this area. Pumping would be required from such a line to serve other District areas. Pumping to the Red line as located to reach Point D appears to be preferable to the use of a gravity line from the Meadowlark Reservoir into the District. Such a gravity line may be an econoirr.oal means of serving the area it can supply after Meadowlark Reservoir may be in use. It does not appear to be a desirable replacement for the Red line to Point D and on to Mt. Kelly. CAPACITY OF AN INITIAL CONDUIT TO THE AQUEDUCT As the comparison of the Red, Green and Black routes shows results favoring the Red line for all capacities for which Mr, Short has prepared cost estimates, the dHacuesion of the size of line which may be built at this time has been limited to the Red line. 63 Hr. Short's estimates cover five sizes of lines having annual flow capacities varying from 900 to 17*000 acre feet. The range covered is adequate for present purposes. However, there is a relatively wide jump from 1,800 to 8,600 acre feet in the sizes used by Mr. Short. To enable intermediate capaci- ties to be considered, the estimates of Mr. Short were plotted and estimates for intermediate sizes secured from the results. The results for eight sizes of line are shown in the following table. The estimated costs are for delivery to Mt. Kelly which, for the Red line, includes delivery to Point D. Estimated Costs of Pipe Lines of Different Capacities Red Line location extending to Point D and Mt, Kelly Water Line Capacity second feet Direct Flow Diameter Capacity acre feet per year of Line in Inches From Results of U7.0 33.0 23,8 5*0 2*5 8 ll.li 316.7 17,OCO 12,000 8,600 1,800 900 2,800 U,ooo 6,000 30-32 26-28 22-2U 12-ali! 10 Interpolated 16 18 20 Estimated Cost of Line to Mt. Kelly Mr. Short 8l,82U,700 1,568,900 1,336,000 701,500 583^800 Results | 83Q),000 970,000 r,350,000 Estimated GTost of Line per acre feet of Annual capacity 0107 130 155 390 650 320 265 200 As is to be expected, these estimated costs per acre foot of annual Delivery increase rapidly for the smaller pipe sizes. There would be economy in building a pipe line large enough to deliver the expected demands for the en- suing 15 to 20 years, if the Carlsbad Municipal Water District would have an available supply from the Aqueduct equal to such excess pipe capacity at the time when it is required to meet increased use in the District, As such an Aqueduct 6k supply is not assured for delivery within 20 years, present pipe line capacities should be based on the water which will be available from the present water supplies. Mr. Short's results for the capacity in seconfl and the annual de- livery in acre feet for the different sizes of pipe show an annual delivery of about 360 acre feet per second foot of capacity. As a second foot flowing con- tinously for a year will deliver J2h acre feet, these results represent operation at an average of one-half of the pipe line capacity. Flow in the Authority Aqueduct is or can be relatively constant as there are storage reservoirs on its lower end. When the demand equals the Aqueduct capacity, the preferential right of the Carlsbad Municipal Water District should be available continuously at the turnout of the District. However, the demand of the District for water deliveries to its users varies during the year. The Carlsbad Municipal Water District cannot use its pipe line continuously at capacity unless it has terminal storage in which the supply can be regulated to meet the demand. Mr. Short has given consideration to this condition in his report and results. His estimated deliveries represent a peak demand equal to twice the average for the year as his results are for direct diversion only with- out terminal storage by Carlsbad,, In his June 1955 report, Mr Holmgren has included the monthly distribution of demand for four units in the Authority (Plate 6). For the Vista Irrigation District and the Fallbrook P. Utility District the use in the maximum month is nearly double the mean. For San Diego the ratio of maximum to mean month is 1»26 and for the La Mesa, Lemon Grove, and Spring Valley Irrigation District it is 1,66. Conditions in the Vista and Fallbrook areas are more nearly similar to those in the Carlsbad Municipal Water District than are those in the other two areas. Mr, Short's assumption that the annual delivery will be one-half of the continouous diversion at capacity appears 65 to be within the range of local practice. Differences that may occur in the future will probably be on the side of increased annual deliveries in relation to rate of flow rather than a decrease. The various sizes of pipe shown by Mr. Short may be able to deliver somewhat larger annual supplies without terminal storage than he has estimated. The Carlsbad Municipal Water District can secure the equivalent of the use of terminal storage by exchange through the use of storage in San Vicente Reservoir. Consequently the size of pipe line should be selected to meet the peak rate of demand for the seasonal use represented by the total acre feet per year to be secured. The aqueduct supply on which the Carlsbad Municipal Water District can rely with sufficient assurance to justify construction of a pipe line for its conveyance at this time has been extensively discussed in earlier portions of this report. It has been concluded that the aqueduct supply available to the Carlsbad Municipal Water District in 1970 may vary from 3*500 acre feet to pos- sibly 5,600 acre feet. It is considered that the Carlsbad Municipal Water District is justified in constructing a pipe line at this time having a delivery capacity from direct flow of 5*000 acre feet per year. Any pipe line that may be built will have a diameter represented by the present commercial sizes of pipe, These vary by increments of two inches. The present construction should be based on the next larger size of pipe which will deliver 5*000 acre feet per year from direct flow. The preceding table shows that this delivery can be secured from a 20-inch line having a capacity of 16.7 sec ft with direct flow delivery of 6,000 acre feet per year and an estimated cost of j>l,150,000. This line is recommended for present construction by the District. It should follow the Red line or San Marcos route and extend to Point D and Mt. Kelly without branches. , 66 WORKS CONSTRUCTED JOINTLY WITH OTHER UNITS There are adjacent units to the Carlsbad Municipal Water District and along the route of the Red line which have need for additional capacity to convey water to their areas from the Aqueduct, It has been proposed that pipe lines for joint use should be built. Mr. Holmgren's plans for the San Marcos Branch in his June 1955 report were based on such joint use. Plate 7 of Mr. Holmgren's report shows a San Marcos Branch from the existing aqueduct to the proposed location of the second aqueduct with a capacity of 90 sec ft. This would be used as a cross connection between the two aqueducts. The branch below the second aqueduct would have a capacity of 129 sec ft for joint use by Oceanside, Carls- bad, San Dieguito, Santa Fe, and areas 2k and 25. This proposed capacity for this branch exceeds that of either of the present two barrels of the Aqueduct. Its estimated cost with extensions as shown on Plate 9 into the areas of the units to be served is stated to be ^,950,000 (p 27). H owever, the estimated cost to be incurred in the district's tentative construction program is only OnL,920,000» This is understood to be based on construction by the Authority of the cross connection with the costs of the remainder of the branch met by the units to be served. It has been suggested that the Carlsbad Municipal Water District can join with other prospective users of the San Marcos Branch to advantage in its cost and operation. Such advantages could result from such joint use, However, to date the writer has not been informed that any adjacent unit is prepared to par- ticipate at this time and has committed itself to any such construction although there have been general discussions. It is concluded that the Carlsbad Munici- pal Water District should encourage any such joint use but it cannot afford to defer its own decision regarding its program waiting for other units to be pre- pared to participate. 67 The problems relating to joint, construction and use of branches by ad- jacent units are closely related to the Authority policy regarding its participa- tion in such branches. This subject has been discussed elsewhere in this report and this subject does not need to be rediscussed here. The present Authority policy on branches works particular hardships on units which have been required to take in large areas of undeveloped lands and are expected to finance all of their branch and distribution costs on their own limited resources. It has also been suggested that if the Carlsbad Municipal Water District should build a pipe line having a capacity in excess of the District's present needs, the District can secure revenue by rental of the use of such capacity to other units. This may represent a source of available income under the conditions stated. However, it is my opinion that the Carlsbad Municipal Water District cannot afford to build extra conduit capacity beyond its own needs in the near future on a hope of such returns. The Carlsbad Municipal Water District will have its OTTO problems in finding sufficient bonding capacity for its own needs without attempting to assist in the financing of other units. If the Carlsbad Municipal Water District should build a pipe line to the Aqueduct for the diversion of direct flow for its use, such a line will neces» sarily not be usable at capacity throughout the year. As previously discussed, Mr. Short estimates an average use of only $0%, by Carlsbad. If there are oppor- tunities to rent the use of any off peak capacity they should be accepted. Such off peak use would be useful to another unit, in general, only to the extent to which it had storage facilities for its regulation. The Carlsbad Municipal Water District is having experience with the use of off peak capacity in its joint use with Oceanside of their pipe line to the Fallnrook-Oceanside Branch. It is not considered that rental of off peak capacity in a Carlsbad Municipal Water District line to the aqueduct represents a dependable source of income of material amount. 68 LOCAL STORAGE Local storage is an essential part of any urban water system. Such storage is required for protection against interruptions in the supply conduits. It is also valuable in enabling larger amounts of water to be taken when avail- able and stored for use in times of deficiency. Local storage would be particularly useful to a unit of the San Diego County Water Authority having a. small preferential right. The water available to such a unit at times when the demand equals the supply may be limited by its preferential right. At other times of the year there may surplus water in the Aqueduct available to be taken if pipe line capacities are large enough. If a constant flow is secured throughout the year, local storage is needed to adjust the supply to the variable demand. In his June 1955 report Mr. Holmgren (Plate 6) has shown the monthly distribution of use for four units in the Authority and also an adopted schedule to determine storage needs for Aqueduct water only. He concludes that storage capacity equal to 2%% of the annual use is needed to convert a uniform monthly Aqueduct supply to the variable monthly use. The storage requirements for this purpose for the four areas shown vary from 8 to 31*8$, The smallest requirement is for the relatively uniform demand of San Diego and the largest for the Vista Irrigation District. The conditions in the Carlsbad Municipal Water District are intermediate between these two areas and the schedule of Mr. Holmgren should fit its needs. To regulate a uniform Aqueduct supply of 1|,000 acre feet per year, local storage of 1,000 acre feet should be available. By varying its draft on the Mission Basin wells the equivalent of some storage may be secured. The Carlsbad Mutual Water Company now has 750 acre feet of storage at Calavera. 69 Mr. Short investigated seven reservoir sites during the preparation of his June 1955 report. He concluded that the best of these sites were the ones known as Mount Hinton and Meadowlark, Mr. ^» B. Bond has also made a report on two sites, the Mount Hinton and San Monas Canyon, Recently Mr. Short has given further consideration to the Mt. Hinton, Meadowlark and Calavera Lake sites. Mr. Short reports that the maximum practical capacity of the Calavera site is about 1,000 acre feet. The present capacity is 750 acre feet. An estimate pre- pared in 195U is stated to have been 070,000 for the filtration system, 050,000 for repairs to the pipe line and $100,000 to raise Calavera dam (Minutes , meeting Board, January 5, 1956, jp,U)» To raise Calavera Reservoir to a capacity of 1,000 acre feet may cost 0250,000. This is a relatively high cost per acre foot for this limited capacity. Present information indicates that Calavera Reservoir should continue to be used to store off peak flows available through the Oceanside system as long as the present agreement with Oceanside is in opera- tion but that the Calavera site should not be enlarged or improved beyond the needs for its use after the Carlsbad Municipal Water District may have secured its own eonnectior to the Aqueduct. If the Carlsbad Municipal Water District should construct a line to the Fallbrook-Oceanside lateral, Calavera Reservoir would have usefulness in the regulation of the water obtained through this line. Present expenditures on Calavera Reservoir for euch use should be limited to its improvement of its present operation. Mr. Short has prepared preliminary cost estimates which show small dif- ferences in the cost per acre foot of capacity for the Meadowlark and Mount Hinton sites. For capacities of less than 20,000 acre feet the estimated costs at the Meadowlark site are somewhat lower than those for the Mount Hinton site. Even at equal cost the Meadowlark site has advantages in location for possible joint use with other Authority units. 70 The Meadowbrook reservoir was included in Mr. Holmgren's June 1955 re- port in the Authority's construction program which also included the second Aqueduct» He used a capacity of 16,000 acre feet with an estimated cost of 01^76^000. This is in agreement with Mr. Short's estimates for various capaci- ties. It is understood that the Authority has secured a three year option to purchase the Meadowlark reservoir site for 0300,000. Mr. Holmgren proposed that the reservoir should be used jointly for areas 2, 13* lk> 2l*> and 25 as shown on Plate 1 of his report. Such joinjy use would result in reduced costs of storage to all participating units compared to separate reservoirs. Additional water may be obtainable at times if the Carlsbad Municipal Water District had pipe capacity for its conveyance and storage for its regula- tion. Some storage in addition to Calavera is desirable if sites can be found at reasonable costs. For the water which the Carlsbad Municipal Mater District can expect to receive from the present Aqueduct and the Colorado River supply of the Metropoli- tan Water District, not over U,QOO acre feet of storage capacity can be justified. Mr. Short's estimates indicate that this may be obtainable at either the Meadowlark or Mount Hint on sites at probable costs of from 0^0,000 to 0550,000. It is probable that the next construction by the Carlsbad Municipal Water District after it has built a line to the aqueduct will be providing local stor- age. Such construction can be deferred until use approaches the supply obtain- able from direct flow plus the available use of storage in San Vicente reser- voir. This period of deferment can be used for further search for available sites. Present information favors the Meadowlark site for storage for the Carls- bad Municipal Water District, It would be undesirable to construct 3,000 to 71 acre feet of storage at this site if this interfered with its later use at larger capacities for joint storage with other units. Raising dams usually materially increases final costs. It may be that by the time Carlsbad requires local storage, other adjacent units will be prepared to proceed with a jointly used reservoir, CONDITIONS WITHIN THE CARLSBAD MUNICIPAL WATER DISTRICT In his June 1955 report Mr. Short has shown the assessed values within the Carlsbad Municipal Water District for four aones. These are Zone I, the Carlsbad area, Zone II the south coastal strip and two divisions of the higher undeveloped lands. The results shown on Mr. Short's Chart 3 are as follows; Estimated Valuations in Percent of Total for the years Zone 1955 1970 2000 n III 3V 19,5 2.U 1.1 62 6 6 fbtal Valuation J IKP 26 2? 5U 8.6 10.U The valuation of Zone II includes the Encina steam plant. This segregation of values has usefulness in relation to the ability to pay for distribution systems and to purchase water. Zones III and IV have only limited present values on which to support costs for their water supply. They have no existing supplies and will need to secure their entire needs from Dis- trict sources. Zone I includes the area served by the Carlsbad Mutual Water Company and will need supplemental water to complete its use. Its present assessed value is sufficient to provide security for the costs of such supple- mental water for Zone I. Zone II includes the service of the Terramar Water 72 Company and the assessed value of the Encina steam plant. This steam plant represents nearly all of the present assessed value of Zone II and will continue to represent a major portion of its value under increased development. Zones III and IV are estimated to increase their assessed values about 7*5 and 16 times respectively by 1970 but would still represent only a small part of the total. The Carlsbad Municipal Water District has an equal responsibility for securing and making available a water supply for all lands in the District, If a partial supply should be secured, each landowner would be entitled to his • share of the available supply. At times of shortage preference would be given to domestic use. Should a partial supply be secured by the Carlsbad Municipal Water District it would be used mainly in Zones I and II due to their larger population and domestic needs. fhese conditions will make it difficult for Zones III and IV to finance local distribution systems even if the main conduits are financed by the Dis- trict as a whole. Until an assured water supply is in sight which can meet the increasing needs of Zones III and IV as they develop, it is my opinion^, that their development should not be undertaken. If a partial supply should be obtained by the Carlsbad Municipal Water District and used in Zones I and II, the lands in Zones III and IV would be taxed for the costs of works from which they would not be benefitted. Their legal right to call for their share of such a supply would have little value if the share they would obtain would not meet an essential past of their needs* Regardless of legal entitlement, the existing conditions will result in the use of any amount of water the Carlsbad Municipal Water District can expect to ob- tain from the present supply of the Authority in Zones I and II. This condi- tion should be recognized and accepted. 73 The inequity of including Zones III and I\T in the District without hav- ing an available present source of water supply for their use can be reduced by continuing the relative low assessed value on these lands and by meeting the costs for conveyance of the Authority supply by taxes or tolls on the areas using the water so secured. This could be accomplished through the use of local improvement districts or by a general district bond issue supported by the assessed value of the entire district with its costs met mainly by tolls on the water delivered. These problems fall mainly in the legal and policy field rather than in engineering. In my opinion, the preferable procedure would be the issuance of general obligation bonds by the Carlsbad Municipal Water District under a com- mittment to us^e tolls, insofar as practicable, to meet bond costs. This would place the cost of such district works on those using the water to be secured but would have the advantage of general obligation bonds over revenue bonds in the cost of financing. As the Carlsbad Municipal Ttfater District does not have at this time a water supply adequate to meet the demandsof all of its area, it is considered that the District should construct only the main supply line to Point D and Mt» Kelly. The locally benefitted areas should meet the cost of local distribu- tion systems. The presently developed areas in Mr. Short*s Zones I and II have existing values which can be used to meet such local costs. This can be done whether through local improvement districts or other forms of suitable local agencies. Before construction of works to convey water to the area of the Carlsbad Mutual Water Company from the District's pipe line is undertaken, a decision should be reached on the form of organization preferred by the owners in this area. The new works should be built by the succeeding organization if the Mutual TJater Company is to be replaced. 7k BECOMMENIED PROGRAM As a result of the numeztoua matters discussed and the conclusions reached in the preceding report a program is proposed which it is recommended the Carlsbad Municipal Water District should adopt and follow. This program has been included in the concluding portion of the Conclusions and Recommenda- tions and is not repeated here.