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r r / <br /> San Joaquin County Environmental Health Department 5747.000.000 <br /> Assessor's Parcel Number 191-330-10, San Joaquin County February 9,2011 <br /> PIEZOMETER INSTALLATION WORK PLAN Page 2 <br /> County Health Department guidelines. The minimum annular space around the well casing will <br /> be 2 inches. All piezometers will be finished in flush-mounted Christy boxes. <br /> The levee crown piezometers will consist of a nested piezometer pair. One piezometer casing <br /> will be screened at a sufficient depth to evaluate under-seepage conditions in conjunction with <br /> the levee and berm toe piezometers and the second casing will be screened within the levee fill to <br /> evaluate through-seepage conditions. The nested piezometers will be isolated with bentonite and <br /> grout seals. <br /> We will develop each well approximately 48 hours following construction using a purge pump to <br /> maximize the hydraulic connection between the well and the surrounding aquifer material. We <br /> have assumed that purge water from well development and soil cuttings from drilling activities <br /> can be distributed over the ground surface at each well location. The top of casing and ground <br /> surface at each monitoring well will be surveyed by survey grade GPS to establish horizontal <br /> coordinates and elevation data. <br /> DATA LOGGING EQUIPMENT <br /> We propose to collect groundwater elevation data from each piezometer with electronic HOBO <br /> U20Water Level Loggers. The data loggers greatly reduce the labor involved in collecting <br /> groundwater data from the piezometers and provide high quality data at specified intervals. The <br /> water level data will be translated into an electronic spreadsheet format and the data for each <br /> well will be plotted versus time to illustrate changes in water levels over time. <br /> The data loggers will be set to record a reading once every hour and downloaded quarterly <br /> during non-flood season river stage conditions. <br /> Installation of the piezometers will be scheduled immediately following San Joaquin County <br /> permit issuance. If you have any questions regarding this letter or our piezometer installation <br /> approach,please contact us. <br /> Sincerely, �Ssaw+L G£o� <br /> ENGEO Incorporat <br /> 2525 � <br /> S <br /> Exp. <br /> 7/3I/2012� <br /> ♦ CERTIFIED # <br /> Sj GEO OGIST �P <br /> Zackrawford,CEG 9rF0 CW,��� <br /> zac/jjt/rc <br /> Attachments: Figure I -Piezometer Location Plan <br /> Figure 2 -Piezometer Installation Detail <br /> Figure 3 -Nested Piezometer Installation Detail <br />