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1 DER <br /> Task <br /> a'roae veaM..aiyn,xwmk. <br /> Task 2 — Piezometer Installation <br /> Six soil borings will be advanced in an area between the H & H Marina and a proposed <br /> recharge trench using an all-terrain, truck-mounted drill rig equipped with 8-inch hollow <br /> stem augers (See attached Figure 1). <br /> Kleinfelder assumes a relatively shallow groundwater depth of about 5 feet below <br /> ground surface (bgs) and a groundwater flow direction to the east. Actual well locations <br /> may be dependent upon utilities and overhead obstructions. <br /> Three shallow borings will be advanced to an approximate depth of 15 feet bgs, and <br /> three deep borings will be advance to an approximate depth of 60 feet bgs. Each <br /> shallow boring will be paired with a deep boring located within approximately 5 feet of <br /> the shallow borings. A 2-inch diameter PVC piezometer will be constructed in each of <br /> the six borings. A 10-foot 0.020 slot screened interval will be used during construction <br /> of each of the piezometers. A PVC screw cap or slip cap (with stainless steel screws) <br /> will be fitted on the bottom of each of the piezometers. <br /> The screened interval for the three shallow wells is anticipated to be installed within the <br /> first 10 feet of first encountered water (estimated from 5 to 15 feet bgs), but not deeper <br /> than 25 feet bgs. The 10-foot screen interval for the deeper well will be installed at an <br /> estimated depth of 50 to 60 feet bgs. The screen depth interval, however, may be <br /> modified based on field conditions, but the 10-foot screen interval will otherwise be <br /> installed between 30 to 60 feet bgs. A clean 2/12 engineered sand will be placed in the <br /> annulus between the boring and casing from the total depth of the piezometer to 1 foot <br /> above screen (shallow wells) to 2 feet above the screen (deep wells). The screen <br /> interval will then be surged using a rigid surge block to settle the sand pack. Extra sand <br /> will be added as needed. A 1- and 2-foot bentonite seal will be placed above the sand <br /> interval for the shallow and deep wells, respectively. After hydration of the bentonite, a <br /> Portland Type II Cement slurry with 1 to 3 percent bentonite powder will be placed <br /> above the bentonite seal to ground surface. The wells will be finished with a locking <br /> pressure cap situated within a monument style (above ground) well vault. <br /> During the advancement of the borings, soil samples will be continuously collected from <br /> the three deeper well borings. No soil samples will be collected in the shallow borings. <br /> Samples from the deeper borings will be collected for lithologic classification and <br /> qualitative field screening, with an organic vapor analyzer (OVA). The OVA measures <br /> ionizable compounds in air in parts per million by volume (ppmv). Lithologic <br /> classification will be based on the Unified Soil Classification System (USCS). <br /> Upon completion of the field activities, Kleinfelder will prepare and submit well <br /> completion reports per the requirements of the Department of Water Resources (DWR) <br /> and will provide a well abandonment permit and report to satisfy EHD requirements <br /> when that process starts. <br /> 87057.E01/ST010L063 Page 2 of 4 June 11, 2010 <br /> Copyright 2010 Kleinfelder <br />