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• Taj Bahadori Page 3 of 5 December 8, 2017 additional funds during this current fiscal year without having to submit a special petition for additional funds to the County Board of Supervisors (BOS). Due to the length of time required to submit this special petition and have this special petition approved by the BOS, the drilling and installation schedule would not be expedited. Therefore, the County proposes to install replacement well G -3E during this fiscal year, likely by March 2018. Well G -3E is selected to be the first new well, because it is nearly mid center along the western boundary of the landfill cells M 1 and M3. Well G-31) generally has one of the lowest water level elevations of the other wells along the western boundary of the landfill. The drilling and installation of each well may take a minimum of five working days due to their considerable depth. The March 2018 time frame for completion of G -3E will allow for EHD well permitting and contracting with a drilling contractor. The County will inform the RWQCB of a more definitive start date at least two weeks prior to the commencement of well drilling. Well Installation - The wells will be drilled and developed by a licensed C-57 Contractor. A mud rotary or air rotary drill rig is anticipated to be used to drill the wells. If the drilling becomes difficult, then a different type of drill rig will be brought in. The bore hole will be logged following visual -manual methods described in ASTM D2488 and under the supervision of a California -registered professional geologist or civil engineer. Drilling spoils will be stockpiled near the boring and dispersed near the vicinity of the boring after well installation. The well casing will be 2 -inch diameter schedule 80, flush -threaded polyvinylchloride (PVC). The well screen will be 2 -inch diameter PVC schedule 80, flush -threaded with 0.02 inch factory cut slots. Centralizers will be used to center the well casing in the bore hole and will be composed of plastic or stainless steel. The sand pack will be #2/12 size, placed in the annulus between the well screen and the boring, and brought to at least two feet above the top of the well screen. A bentonite seal will consist of sodium montmorillonite clay. The bentonite seal will be at least two feet in vertical thickness and will be placed above the sand pack prior to grouting the remaining well annulus. The neat cement well seal above the bentonite seal will consist of Portland Type II cement and have a bentonite mixture of 5 percent by weight. The concrete surface completion will have minimum of 28 -day compressive strength of 2,500 psi. Well casing plug will be an expansion type, which provides a water tight seal, and have connections for the discharge tubing and the lead wire. The well enclosure will be a minimum 8"x 8" square, made of galvanized steel and have a lockable cover with a padlock. Well Development - The drilling contractor will allow a minimum 48 hours for the neat cement seal to set. The contractor will develop the well within 7 days of completion of the well. The contractor will develop the well using mechanical surging or over pumping or a combination thereof. Development of the well will continue until: • Well water is clear to the unaided eye • Sediment in the well casing is less than 0.1 foot thick North County 2017 NOV Final 120817.docx