SITE INFORMATION AND CORRESPONDENCE

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cement-bentonite grout. The wells will be completed below grade and covered with a Rush- mounted,traffic-rated Christy box. A concrete surface seal will be placed around the Christy box. Monitoring well construction will be implemented in accordance with SJC-EHD well standards and permit requirements. An example of a monitoring well construction detail is provided in Appendix A. 4.5 Well Development Each monitoring well will be developed (1) to remove fine-grained materials inside the filter pack and well casing and (2) to stabilize the filter pack around the well screen in order to produce representative groundwater samples. The monitoring wells will be developed using either a submersible pump or by surging/bailing. Well development will take place after the well seal has bonded to the well casing. A minimum of three to five volumes of standing water inside the wells will be removed during development. Well development will continue until the field water quality parameters and the clarity of the water have stabilized. Well development logs will also be prepared. An example of a well development log is provided in Appendix A. 4.6 Wellhead Suryffin Wellhead elevations (determined by the top of PVC well casing and the Christy box rims) and their respective locations will be measured by a licensed surveyor. Wellhead elevations and groundwater elevations will be measured from a common reference point at each wellhead. The reference point will be a small V-notch cut into the top of the north side of each casing after the well has been installed. The wells will be surveyed relative to a nearby benchmark and/or a U.S. Geological Survey benchmark having a vertical datum point referenced to Mean Sea Level (MSL). Planar coordinates for the monitoring wells will be generated to establish accurate horizontal control. Preliminary Site Investigation Work Plan-Final July 9, 1998 Roberts Property(Former Vemalis Pump Station) Vernalis,California 12