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Home My WebLink About1999-04-13; Municipal Water District; 439; Report on Carlsbad Water Resources PlanCARLSBAO MUNICIPAL WATER DISTRICT -AGENDA BILuw / AB# ‘$37 TITLE: “?ak DEPT. HD. MTG. 4/l 3199 REPORT ON CARLSBAD WATER RESOURCES PLAN CITY ATTY. cE3 DEPT. CMWD . RECOMMENDED ACTION: Receive and file the Carlsbad Municipal Water District Local Water Resources Plan. ITEM EXPLANATION: The Carlsbad Water Resources Plan was authorized by the Board on June 18,1996, by Resolution No. 944. It was jointly funded by the Carlsbad Municipal Water District (CMWD) and the San Diego County Water Authority (SDCWA). The CMWD contracted with Carollo Engineers to prepare the Master Plan. The purpose of the plan was to determine the appropriate mix of alternative water supplies that would increase water supply reliability and reduce CMWD’s dependence on imported water. The plan discuses current programs that might affect the reliability and cost of imported water, the only source of potable water available to CMWD. In addition, the potential local resources are discussed and the recommended water resources are presented. The study area covers the entire area of the City of Carlsbad, approximately 40 square miles. The City’s different land use designations were identified from the 1994 General Land Use Plan, and this information was used in projecting the ultimate water demand. Within CMWD’s service area of 32.11 square miles the ultimate average day water demand at build-out was estimated at 23.58 million gallons per day (mgd). However, in addition to this demand an estimate was made of the potential recycled water demand that would occur within the entire City limits. The combined water demand of CMWD plus recycled water demand within the entire City increases the overall water demand to 2‘5.4 mgd. This water demand would need to be met by the available water resources. Recent studies by the SDCWA, and the Metropolitan Water District of Southern California (MWD), indicate that imported water supplies to CMWD could be reduced to a 75 percent level of reliability. This reliability level implies that there would be a 25 percent reduction of the imported water supplies normally available to the CMWD during drought conditions. This level was noted in MWD’s recent “Drought Management Plan”, and the SDCWA’s “Water Resources Plan of 1997”. To increase the reliability level for CMWD requires developing local water resources. Local water resource development is encouraged by both SDCWA and MWD to meet the overall Southern California water supply needs in the next 20 years. Page 2 of Agenda Bib UIO. .sL The water resources available to the CMWD include recycled water, groundwater, surface water, seawater desalination, conservation, and joint projects with adjacent agencies. These water resource opportunities were analyzed with respect to cost, potential resource size, water quality with respect to total dissolved solids (TDS), environmental impacts, and reliability. It was concluded that, in addition to imported water through the SDCWA, five other candidate resources could be developed including: 1. Recycled Water 2. Groundwater from Mission Basin in Oceanside 3. Seawater desalination 4. Increased Conservation 5. Imported water from the Mount Israel Project Item 5 above assumes that CMWD would participate with the Olivenhain Municipal Water District in developing an advanced microfiltration treatment process at the proposed Mount Israel Reservoir now in design by the SDCWA. This project has several advantages including improved water quality. However, it was subsequently removed from further consideration due to its relatively high cost and with little or no increase in reliability to the CMWD. Following is a discussion on the final recommended resources: Recvcled Water Phase I of the recycled water program is complete and in operation and supplies a maximum flow of 2.75 million gallons per day (mgd) in Carlsbad. An analysis shows that a maximum day demand of 20 mgd could be the potential recycled water demand within the City of Carlsbad with 18 mgd being the most practical to develop. The increase in supply over the current 2.75 mgd system could be accomplished by developing four more phases. It is recommended that Phase II now be developed to increase production to 8 mgd consisting of the following: 1. Construction of a new 4.25 million gallons per day (mgd) water reclamation plant on the parcel south of the Encina Water Pollution Control Facility. 2. Expansion of the Meadowlark Water Reclamation Plant by an additional 1 .O mgd. 3. Conversion of the existing Mahr and Lake Calavera Reservoirs for seasonal storage. 4. Developing 74,000 feet of transmission and distribution pipelines. 5. Construction of booster pumping stations. Mission Groundwater Basin The Mission groundwater basin is located along Highway 76 in Oceanside. The project calls for developing existing appropriate groundwater rights of 5 cfs, and additional permitted rights of 5 cfs. The groundwater has a relatively high TDS of 1500 mg/L and requires desalination to lower the TDS to recommended State Health standards. Page 3 of Agenda Bilr ldo. 437 At this time the SDCWA in association with CMWD, Oceanside, Camp Pendleton and Rainbow Municipal Water District are actively investigating the possibility of storing imported water in the basin during the winter months and withdrawing the water at peak demand periods. The imported water, having a lower TDS, would displace the higher TDS water and eliminate the need for desalination. This is referred to as aquifer storage and recovery. To use this groundwater source, it is not practical for the CMWD to construct new wells and pipelines from the basin to Carlsbad, nor construct and operate a separate desalting facility. The groundwater would probably best be developed through a cooperative agreement with the City of Oceanside. The CMWD would obtain a quantity of water from Oceanside relative to the water rights of each agency. The water could be delivered through Oceanside’s pipeline distribution system to CMWD under a wheeling arrangement. Seawater Desalination Seawater desalination is not presently as cost effective as some other sources, but could become an important element to maintain reliability. The cost to desalinate seawater was estimated at $1200/acre-foot. However, the cost for this water has been decreasing substantially over the last few years because of improved reverse osmosis membranes, lower capital cost, and higher efficiency pumps. As an example, the City of Tampa Bay in Florida is near a decision to construct a 20 to 25 mgd facility that would deliver desalinated seawater for approximately $700/acre-foot. By comparison the cost for imported water from the SDCWA is $516/acre-foot. For Carlsbad it is proposed that a portion of the site south of the Encina Water Pollution Control Facility be set aside for a desalination plant. In the near term, preliminary investigations would be made into methods to supply seawater to the plant, determine the best method for brine disposal, research the latest desalination technologies, perform environmental reviews, and research grant funding. Conservation Approximately, 5 percent additional reduction in water demand is possible through installation of new equipment technologies such as horizontal-axis clothes washing machines and advanced dishwashers, and utilizing more low water demand plant schemes and innovative irrigation systems. SUMMARY Exhibit 2 summarizes the recommended water resources by water production. Figure 1 shows the combined water resources compared to water demand. If the local resource projects are implemented the reliability level could increase to 87 percent. The capital cost and annual cost are shown in Exhibit 3. The annual cost includes operation and maintenance costs plus annualized capital cost. The Mount Israel project is shown for comparison purposes, but is not recommended for further consideration. 0 ‘3 Page 4 of Agenda Bilr ldo. 435 FISCAL IMPACT: There is no fiscal impact as a result of this recommendation. EXHIBITS: 1. Table 1 titled, “Selected Resources Capital Cost Summary.” 2. Figure 1 titled, “Carlsbad Municipal Water District, Water Resource Mix with Maximum Recycling, Local Supply and Imported Water.” R.\CMWD\Word\Word - 99\Agenda BIII -WRP.doc E 0 rs E .m 2 m E 0 .rl 2 .rl E h E 7 0 E \ 0 K (ami) uwmmmd 2431VM 1WlNNV 39W3AV