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1 3.0 MONITORING WELL DESIGN As stated in the WDRs, groundwater monitoring wells are to be designed and sited to ensure that water quality at storage pond sites and land application areas is adequately characterized and any potential water quality impacts from the ' discharge are detected. The wells shall yield samples representative of the uppermost portion of the first aquifer underlying the pond sites and land application areas. ' General monitoring well design is illustrated in Figure 2a (above ground ' completion) and Figure 2b (below ground completion). These designs are consistent with SJCEHD and State of California Monitoring Well Standards. A description of these monitoring well designs includes: (1) the well casing, ' perforated over the targeted depth interval for monitoring; (2) the annular spacing between the perforated well screen and borehole, filled with a filter pack; (3) a transition seal placed on top of the filter pack; and, (4) a sanitary seal which ' extends upwards from the top of the transition seal to land surface. Additional details on monitoring well casing, filter pack, seals, and completions are described below. ' 3.1 Well Casing ' The well casing shall be ASTM, API and/or AWWA approved. Its perforated length (well screen) and diameter shall be selected to provide samples representative of the uppermost portion of the first aquifer, provide adequate clearance for water-level and water sampling devices, and produce sufficient yield for adequate purging and sampling$. All well-casing joints shall be flush- threaded and watertight. The bottom of the well shall include a minimum 1-foot solid casing sump, sealed with either a flush-threaded or slip cap (if a slip-cap is utilized it shall be secured with threaded stainless steel screws). ' 3.2 Filter Pack The annular spacing between the well casing and formation shall be filled with ' clean filter pack material matched to the slot size of the well screen. The objective for the filter pack material is to exclude the entrance of fine silts, sands, and clays into the monitoring well yet provide sufficient well-yield for effective well ' purging and sampling. Filter pack material shall be nonreactive, not degrade or consolidate after placement, and obtained from clean sources and properly packaged for handling, delivery, and storage. Filter pack material shall be placed in the well boring to a depth of 1-foot above the top of the well screen using a tremie pipe or equivalent. The filter pack depth shall be checked, and the volume of filter pack material considered for verifying 8 Water-level and water sampling equipment and procedures are described in the Sampling and Analysis Plan provided as Appendix D.