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Central Valley Regional Water Quality Control Board 6375.4.002.01 Yosemite Avenue Properties December 6, 2004 WORK PLAN FOR GROUNDWATER STUDIES Page 2 Drilling will be accomplished using the hollow stem auger flight drilling method. Soil samples will be collected at various depths using a California Split Spoon Sampler containing three 2rhinch-diameter by 6-inch-long brass tubes. Select samples will be retained for potential laboratory analysis. We will seal each end of the brass tubes using tight-fitting plastic caps. Well casings will be installed so that the manufactured well screens are between 5 and 20 feet below the ground surface (bgs). The well screens will be appropriate for the graded granular filter pack material that will be sized according to the aquifer material grain size distribution encountered during our geotechnical explorations at the site. Granular material will be placed between 3 feet bgs and the total depth drilled at each location. The upper 3 feet of annular space will be filled with a thin separating layer of bentonite and then a cement grout to minimize the intrusion of surface water into the well. We will extend the well casing between 2 to 3 feet above the ground surface and install a steel standpipe to protect the well casings and the data logging equipment that will later be installed. Each well will be developed immediately following construction using surge blocks and bailers to maximize the hydraulic connection between the well and the surrounding aquifer material. We have assumed that purge water from well development and soil cuttings from drilling activities can be distributed over the ground surface at each well location. To provide a preliminary characterization of the subsurface conditions, the data from the monitoring wells will be reviewed for evidence of lateral changes in soil, both above and below the groundwater surface, which may influence flow in the shallow aquifer explored. LaboratoryTg Representative soil samples from our exploratory locations will be tested in our laboratory to determine some of their pertinent properties. We currently plan to perform moisture contents, density, sieve analysis, and hydrometer testing for this project. Survevine We will retain the services of a licensed land surveyor to establish horizontal coordinates and elevation data for each of the five wells. Elevation data provided by the surveyor will include the top of well casing,the top of the concrete monument for the well, and the ground surface at the well. We will request the surveyor tie the survey of the wells to the nearest documented benchmark to establish elevation control. Water Level Data Collection Each shallow monitoring well will be equipped with a pressure transducer that will allow for automated data collection and efficient data retrieval. We propose to use the Global Water