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Work Plan- Site Characterization II Page 6 <br /> Former Karlson Trucking Facility <br /> Project No. 191.2 <br /> December 6, 1999 <br /> 2.2 Monitoring Well Construction, Development & Sampling <br /> 2.2.1 Monitoring Well Construction <br /> Groundwater monitoring wells will be constructed in each boring upon their <br /> completion to total depth. The casing for each well will consist of 2 inch <br /> diameter, flush threaded Schedule 40 PVC. Blank casing will extend from <br /> ground surface to 5 feet below grade. The screened interval will be <br /> constructed using 0.010 inch slotted casing and will extend from 5 to 20 feet <br /> below ground surface. A plastic end cap will be screwed onto the bottom of <br /> the screen to cap the bottom of the well. Number 3 sand will be used for <br /> filter pack from total depth to two feet above the top of the screened interval. <br /> Prior to installation of a two foot thick bentonite transition seal, the well will <br /> be surged using a surge block to settle the filter pack material. The <br /> remaining annulus above the bentonite transition seal will be filled to grade <br /> with neat cement grout. The top of each well outside of the building will be <br /> secured in a traffic rated well box and a watertight locking well cap installed <br /> on the top of casing to prevent surface water infiltration into the well. (See <br /> Figure 3 for a generic well construction schematic). <br /> It is also proposed that the existing well, MW-5 be filled by pressure grouting <br /> with cement grout. It is anticipated that approximately 1.75 cu. ft. of neat <br /> cement will be needed to pressure grout the monitoring well. <br /> After the two monitoring wells have been constructed, they will be surveyed <br /> by a licensed land surveyor to ±0.01 foot accuracy in the z direction and ±0.1 <br /> foot accuracy in the x and y directions. The wells will be surveyed relative to <br /> an on site fixed point of reference, usually the corner of a building, or, if <br /> available, a nearby surveyed benchmark. <br /> 2.2.2 Monitoring Well Development <br /> After the well materials have set up (>48 hours) each well will be developed <br /> using a submersible pump. The wells will be pumped at a steady rate until a <br /> clear stream of water is obtained. All development water will be <br /> containerized in appropriate containers on site until appropriate disposal <br /> arrangements can be made. <br /> 2.2.3 Monitoring Well Sampling <br /> Upon arriving on-site all the wells will be opened the depth to water <br /> measured using an electrically actuated sounding tape. The water level <br /> 2937 Veneman Avenue, Suite B240 Geo-Phase Environmental Inc. Phone: (209)569-0293 <br /> Modesto, Ca 95356 Fax: (209)569-0295 <br />