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0 0 Section 2 Proposed Hydrogeologic Investigation requirements,percolation, and canal or reservoir leakage. To achieve quality measuring results it is very important to take into account several factors that may influence the measurement: the surface vegetation,the extent to which the soil has been compacted, the soil moisture content and the soil layers (strata). The best measuring results are obtained at field capacity of the soil. Factors that affect the infiltration rate: soil structure,layering, degree of saturation, chemical and physical properties of the soil and liquid used,head of the applied liquid, and the diameter and depth of embedded rings. This method does not address hydraulic boundary conditions. The results of these short term duration tests form the basis of the infiltration rates which are affected by the long term effects of treated wastewater effluent suspended and dissolved and the expected effects of different land management practices upon infiltration rates. 2.3.4 LIMITED DURATION PUMPING TESTS Assessing the possible fate and transport of wastewater effluent(lateral escape)is an important component of an evaluation of disposal options. Such an assessment requires estimates of the hydraulic conductivity of the soils of the underlying aquifer. This hydrogeologic investigation will include low-rate pumping tests (limited duration-pumping tests)in the new monitoring wells. These data will be used to compute aquifer properties such as hydraulic conductivity and transmissivity. Initial analysis of the drawdown data will be accomplished using the Cooper-Jacob approximation of the Theis equation and these results will provide "seed values"of transmissivity for subsequent detailed analysis of the data using a computer program such as AQTESOLV for Windows,by HydroSOLVE, Inc. A pumping test is a far superior means of measuring the hydraulic conductivity of saturated soils than other methods such as slug testing, and can be easily performed in monitoring wells as small as 2 inches in diameter. The limited duration-pumping tests will be preformed in conjunction with sampling activities. 2.4 GROUNDWATER CHARACTERIZATION AND HYDROGEOLOGIC EVALUATION REPORT Upon completion of four quarters of groundwater and San Joaquin River monitoring, and collection of field hydrogeologic parameters, a Groundwater Characterization and Hydrogeologic Evaluation Report will be. This report will evaluate possible evidence for the interaction between San Joaquin River and adjacent groundwater and summarize seasonal groundwater flow directions and gradients, and initial assessment of"background" concentrations of the constituents monitored. Results of the field and laboratory hydrogeologic investigation will be documented in the report and used in an assessment of the potential suitability of the land for use as storage,percolation disposal, and/or irrigation disposal of effluent. Additionally, a preliminary mounding analysis will be performed using simplified equations developed for modeling a groundwater mound such as those developed by Hantush(1967) for a circular percolation area. The mounding analysis will evaluate the potential interaction between multiple rapid infiltration basins and provide an May 2006 Main Stone Property 24 Effluent Storage and Disposal Site Hydrogeologic Investigation Workplan