WORK PLANS - Laserfiche WebLink

Home Browse Search

• w slowly dropping the material through a tremie pipe from the surface. Frequent measurements will be made to reduce unrecognized bridging of the sand pack. The hollow stem auger will be gradually removed from the borehole as the sand packing progresses. The sand pack material will extend along the length of the perforated section to no more than 2 feet above the top of the screen. A minimum two-foot thick seal of bentonite pellets will then be placed on top of the filter pack and allowed to hydrate.The pellets will be hydrated by pouring deionized water into the annular space. The grout seal will then be mixed and pumped through a tremie pipe into the annular space. The hollow auger will be gradually removed from the borehole as the grouting operation progresses. MW-5R will be completed at the surface using a traffic-rated well cover. The well cover will be installed approximately'/4-inch above grade to reduce the entry of surface waters and fixed in place with concrete. Task 4-Monitoring Well Development The well will be developed to reduce the effects of drilling on the formation and to increase the effective hydraulic radius of the well. Monitoring wells are generally developed 24 to 48 hours after installation to allow the grout to set. The well will be developed by surging,pumping,or bailing. Surging along the screened interval of the well is performed to draw the sediment from the formation into the filter pack and the well and to set the sand pack.The sediment-laden water will be purged from the well at a rate of between 0.75 to 10 gallons per minute(gpm)depending on recharge rate.Development will continue until the discharge runs relatively clear of fines.Approximately 5 to 10 well volumes will be removed from the monitoring well.Because MW-5R is an upgradient well and not affected by site activities,the development water will be discharged directly to the ground. Task 5-Well Survey The elevation of the top of the PVC casings will be surveyed and tied into permanent markers, if readily available. Survey accuracy will .01 foot Task 6—Well Installation Report CKG will prepare a brief Groundwater Well Installation Report. This report will document the well drilling activities, boring log, well construction details and well development. CKG will also prepare and submit the California Department of Water Resources Well Construction Report. After the well installation is completed the well will be incorporated into the existing groundwater monitoring program. CKG Environmental,Inc. Page 3 November 3,2017 Well Installation Work Plan Owens-Brockway Tracy CA