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KLEINFELDER 1 The well borings will be advanced using a truck-mounted drill rig equipped with 8-inch hollow stem augers. During the advancement of the well borings, soil samples will be collected at 10 foot intervals and at each significant lithologic unit for lithologic classification only. Discrete samples will not be collected in coarse gravel and cobble zones. Lithologic classification will be based on the Unified Soil Classification System. Currently, based on our experience, we do not a anticipate encountering groundwater during advancement/installation of these two monitoring wells. s Two 2-inch.PVC monitoring wells will be installed in each of the two borings. Based upon the reported elevation and depth of the Delta Mendota Canal invert (approximate elevation 170 feet above mean sea level and a depth of 20 feet), the shallow monitoring wells will be screened from approximately '15 to 35 feet below ground surface (bgs)'. The proposed screened interval is estimated to span a depth of approximately 5 feet above and 15 feet below the Delta Mendota Canal invert. The monitoring wells will be generally constructed as described for monitoring wells in Attachment B. The monitoring well locations and elevations will be surveyed either by a DSS or KIeinfelder subcontractor, so that subsequent water level sounding data can be utilized in determining groundwater flow directions and gradient as described in Attachment B. Task E03 —Monitoring Well Development and Well Survey (Optional Task r A°minimum of forty-eight Hours after installation? the two new monitoring wells may be developed ' to remove sediment from the bottom of each monitoring well, remove sediment laden water, and to increase the hydraulic radius of the monitoring wells. KIeinfelder anticipates the two shallow wells 7 will be diy'and therefore will not need to be developed. However, if water is present, the wells will be developed based upon approval of Task E03. Development will be performed using a pump and/or bailer as generally described in Attachment B. Kleinfelder understands the top of casing of each of the two new wells and three existing production/irrigation wells will be surveyed by DSS personnel for location and elevations. Elevations will be surveyed to the nearest 1/100"' of afoot. Task E04—Well Sampling and Monitoring DEEP IRRIGATION/PRODUCTION WELLS Water level measurements will be made in three existing irrigation/production wells (Plate 1) at the beginning of the sampling round prior to purging and sampling the wells. The depth to groundwater will be measured in each well according to the protocol described in Attachinent B. The depth to water measurements will be converted to relative groundwater elevations with respect to mean sea level or a local benchmark by subtracting them from the surveyed casing elevations. '1 1 r 20-YPO-212/2000P2561200OW022 Page 3 of 7 OO 2000 IUeinfelder, Inc. July 25,2000