AgdaPkt 2004-03-22 - Laserfiche WebLink

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�. � �5� MEMORANDUM Community Development Department Engineering & Construction To: Chu Chang Date: March 1, 2004 From: Tonia Tabucchi RE: INITIAL WELL WATER INFORMATION In an effort to reduce the City's potable water demand, the Recycled Water Task Force requested that the City research the possibility and cost to drill a well for irrigation use. The County of San Mateo (County) and three well professionals were contacted. Some of the information requested by the Task Force were the possible cost of drilling a well, quality of water, current well usage, and location and availability of water. According to the County, Redwood City's water service area lies in the San Mateo Pl�in Groundwater Basin. The information available is lacking because a study of this basin has not been conducted. Once a study of the basin is conducted, a groundwater management plan can be developed, production of the basin being one of the plan's components. Since 1987, the County has been permitting irrigation wells within the City's water service , boundary. There are nearby agencies that have permitted wells for potable use. A map was provided by the County displaying the location of the permitted non-monitoring wells within the service area. Residents have successfully drilled irrigation welis; however, the information concerning the depth of bore, size of casing, and production and quality of the well is not kept on file in the County. Therefore, this information is not available for study. Based on their experience, both the County and the Well Professionals feel that thesupply and the quality of groundwater for would be sufficient for irrigation use. Red Morton Park was a suggested example. In terms of cost, an Engineer and two well drilling companies were contacted. Red Morton Park was given as a possible well location. To further determine the water quality, depth of water, and composition of the aquifer, a test weli can be drilled. A test well is a smaller bore in which an electroresitivity log can be conducted to find the aquifer, which can be pumped to find out the production. The test well can be reamed out to an 8" (minimum) casing, providing 100 GPM, as suggested by the contacted well orofessionals. The cost of retrofitting the irrigation system and bringing power to the pump is difficult to estimate until the exact location is chosen and reviewed in greater detail; however, a 350 feet deep irrigation well with the above specifications, complete with tests, pump and auto controls, would be approximately $250,000. TT:ss