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3.02.3 Water Source <br /> A. Water used for well construction and development shall be obtained from <br /> the onsite water supply well. Drill and development rigs holding tanks <br /> shall be flushed with onsite water to remove residual water in the tanks. <br /> 3.03 INSTALLATION <br /> 3.03.1 Drilling Method <br /> A. The drilling method shall prevent the collapse of formation material <br /> against the well screen and casing during installation of the well. The <br /> inside diameter of any temporary casing used shall be sufficient to allow <br /> accurate placement of the screen,riser,centralizer(s),filter pack, seal and <br /> grout. The use of drilling aids such as bentonite, other clay-based agents, <br /> or any other foreign matter capable of affecting the characteristics of the <br /> ground water is prohibited. Any drilling fluid additive must be pre- <br /> approved by the Owner before use. Grease or oil on drill rods,casing, or <br /> auger joints are not permitted;however,PTFE tape or vegetable oil (in <br /> solid phase form)are acceptable. The drill rig shall be free from leaks of <br /> fuel, hydraulic fluid, and oil which may contaminate the borehole, ground <br /> surface or drill tools. During construction of the wells, precautions shall <br /> be used to prevent tampering with the well or entrance of foreign material. <br /> Runoff shall be prevented from entering the well during construction. If <br /> there is an interruption in work, such as overnight shutdown or inclement <br /> weather, the well opening shall be closed with a watertight <br /> uncontaminated cover. The cover shall be secured in place or weighted <br /> down so that it cannot be removed except with the aid of the drilling <br /> equipment or through the use of drill tools. <br /> 3.03.2 Sampling <br /> A. Samples shall be taken of all materials penetrated by each drilled well/test <br /> hole. Soil sampling shall be done with a stainless steel split tube sampler <br /> using standard sampling techniques in accordance with ASTM D 1586. <br /> Samples shall be extracted from their in-situ environment in as near an <br /> intact, minimally disturbed condition as technically practical. Samples <br /> shall be retrieved according to ASTM D 1586 at least every 10 feet from <br /> each boring. Drive-sampled materials shall be placed in airtight <br /> containers and labeled. Description and identification of soils shall be <br /> done in accordance with ASTM D 2488. Sampling shall be performed to <br /> allow completion of the documents described in paragraph Borehole Logs. <br /> Foothill Landfill Site Improvement Project 5 GROUNDWATER MONITORING WELLS <br /> San Joaquin County Public Works Section 02522 <br />