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Home My WebLink About03/12/2002, SS 1 - CITY OF SAN LUIS OBISPO WATER SYSTEM MASTER PLAN council March 12, 2002 j aGEnba Report h=".,ba ss C I T Y OF SAN LUIS OBISPO FROM: John Moss,Utilities DirectR(P- Prepared By: Gary Henderson, Water Division Manager SUBJECT: CITY OF SAN LUIS OBISPO WATER SYSTEM MASTER PLAN CAO RECOMMENDATION Receive and file the report and consider specific projects as they come forward in future financial plans. DISCUSSION Background Several years.ago, in conjunction with the development of the Airport Area Specific Plan, the City of San Luis Obispo initiated the development of a Water System Master Plan (MasterPlan). The Water System Master Plan was prepared by Boyle Engineering Corporation through subcontract with Wallace, Roberts, and Todd (the lead consultant for the Airport Area Specific Plan). The overall purpose of the Master Plan was to evaluate the existing raw water delivery facilities, the water treatment plant, and the water distribution system to identify existing deficiencies and necessary improvements needed to meet both existing water demands as well as full build-out as identified in the City's General Plan. The Master Plan was developed over a number of years and some of the recommended minor improvements have already been completed. The overall evaluation indicates that the water system has been relatively well planned in the past but there are some major capital improvements that will be necessary to correct existing deficiencies and to meet future water demands for new development. Staff will prioritize recommended system improvements and include projects in the City's Financial Plan (CIP). In fact, several projects are included in the 2001-03 Financial Plan. Raw Water Delivery and Water Treatment Plant The raw water delivery systems from Salinas and Whale Rock Reservoirs can provide approximately 8.0 million gallons per day (MGD) and 12.2 MGD respectively. The existing water treatment plant is located approximately one half mile north of Highway 1 on Stenner Creek Road (near Cal Poly). The water treatment plant was upgraded in the early 1990's and has a design capacity of 16.0 MGD. The current design capacity is deemed sufficient to meet future water demands at full build-out as identified in the General Plan. There are a number of capital improvements to increase reliability and improve operations at the treatment plant. The main areas identified for additional study and improvement at the water treatment plant are listed below: /- 1 Council Agenda Report—Water System Master Plan Page 2 1. Seismic evaluation of the existing treated water storage reservoir (clearwell) and Washwater Reservoir No. 1. 2. Evaluate potential for Reservoir No. 2 to provide the Water Treatment Plant fire protection and water supply. 3. Recoat and repair existing 4.0 million gallon treated water reservoir(clearwell). 4. Construct second treated water reservoir to improve operations and reliability. 5. Raise washwater inlet control structure. 6. Construct second sedimentation basin in the future if supplemental water sources are obtained or water demand warrants need for second sedimentation basin. Items 1 through 5 above will be included in a request for proposals for study and design. The first phase of the project will include the seismic evaluation of the existing steel storage tanks, siting and size requirements for the new treated water storage tank, evaluation of the ability to supply water for the treatment plant from Reservoir No. 2 (up Stenner Creek Road at the old treatment plant site), and improvements at the Transfer Pump Station (which are identified in the Water Distribution section of the Master Plan). Following completion of the first phase, the development of the plans and specifications for the recommended improvements will be undertaken. Item 6 above will be deferred until clearly identified as needed in the future. Water Distribution System The analysis of the water distribution system involved the development of a computer model to evaluate system performance under various operation scenarios. The evaluation included all the pump stations, storage facilities, and pressure regulating valves throughout the entire City water system. The model included most of the distribution pipelines to provide the backbone system for evaluation of potential deficiencies. The model was used to evaluate the ability of the system to meet current as well as build-out needs within the community. The fire flow requirements for various areas are typically the most critical factor for determining pipe size and storage tank requirements. AA/MA Distribution System The Airport Area, as well as the Margarita Specific Plan area, were evaluated using the same computer hydraulic model to determine the backbone infrastructure necessary to provide water service to these areas. The analysis identified the need to install a looped water system consisting of 10", 12", and 16"water mains in the area to meet fire flow and customer demands. The study identified the need for approximately 2,250 feet of 10" main, 37,450 feet of 12" main, and 440 feet of 16" main. This will provide the backbone water system for new development in the area. Individual developments will be responsible for installing the 8" mains to serve specific 1z i Council Agenda Report—Water System Master Plan Page 3_ developments within the area. The total cost estimate for the backbone water system is estimated at$4,550,700. Other System Improvements For the most part, the analysis of the existing water distribution system revealed that the system can meet existing as well as future water demands. There are a number of deficiencies that staff was aware of that were confirmed by the hydraulic analysis. The.computer program was then utilized to identify recommended system improvements necessary to meet the fire flow and customer water demands. The main improvements recommended to correct the noted deficiencies are listed below and noted on Attachment 1 to this report: 1. Replace existing 0.1 MG Bishop Tank with a new 1.2 MG storage tank. 2. Various upgrades to existing pump stations . to meet operational and fire flow requirements (mainly installation of high capacity fire pumps). 3. Abandon Highland Tank and serve area from Fetrini Tank through existing pressure regulating valves. In addition, construct new pump station at the appropriate elevation to provide water to the Rosemont Tank. 4. Replace the existing Alrita Pump Station with new facility designed to meet fire flow and water demands in the Alrita area (an alternative would be to construct a 0.2 MG tank on the hillside above Alrita Street). 5. Replace numerous undersized 6" mains with 8" mains throughout the existing distribution system to meet design criteria(fire flows, water velocities, etc.). 6. Construct new 0.2 MG water tank in Prefumo Canyon area to correct low pressure and fire flow deficiencies. Item 1 above is by far the most significant project identified for improving existing deficiencies in the water distribution system.. The existing Bishop Tank is located on the hillside behind General Hospital. The storage tank serves the area east of Johnson Ave from near French Hospital to Orcutt Road and also includes the area east of Augusta from Bishop Street to Laurel Lane. This is a large service area and the tank is significantly undersized to meet the needs of the area. The analysis determined that the tank should be replaced with a storage tank 12 times as large as the existing tank (0.1 MG to 1.2 MG). This project will require significant planning and design efforts. The increased storage capacity in this facility can also provide backup water service to the Terrace Hill zone in the event of an emergency situation. The construction of this new storage facility to serve the Bishop area, as well as the Terrace Hill zone, will greatly improve reliability and service during power outages, wild land fires or other system emergencies. J-3 Council Agenda Report—Water System Master Plan Page 4 The projects identified above will be brought forward as part of future Capital Improvement Project budgets for Council approval. A number of these projects are currently included in the Water Distribution Master Plan Implementation Project in the 2001-03 Financial Plan (pages 124-127). The remainder of the projects identified in the Master Plan will be prioritized by staff and included in future budgets as funding allows. Summary The Water System Master Plan was developed to identify necessary improvements to provide reliable water service to the community. The Master Plan revealed that the system, for the most part, has been properly designed to meet the fire flow and customer demands in the community. There are some areas that require improvements to correct existing deficiencies as well as improvements necessary to meet the needs of new development. The improvements recommended in the Master Plan will be prioritized and brought forward for Council consideration as part of the City's Financial Plan process. CONCURRENCES The Fire Department was involved in the development of the criteria for identifying system improvements. Many of the improvements are necessary to meet fire flow demands in various areas around the City. The Fire Department concurs with the recommendations in the report to increase fire protection throughout the community. FISCAL IMPACT There is no immediate fiscal impact associated with this report and the recommended action. The recommended system improvements which will be funded by water rates will be incorporated into future budgets and the associated impacts will be evaluated during annual water fund rate reviews. The improvements necessary to serve new development will be incorporated into the Water Impact Fees charged to new development and are being provided to Council in separate reports at this study session. ATTACHMENT: 1. Major proposed water system improvements * Full copy of the Water System Master Plan is in the Council reading file. ATTACHMENT 1 f f } � a N G 1�- r ? 6y -.r m Q N O O w z a`