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v 0 11. Contractor shall add sand shall until the sand pack is above the top of the screened interval as shown on the groundwater well figure. 12. Once the placement of the sand packed interval is completed, the contractor shall measure and record the depth to the top of the pack in the presence of the Engineer. 13. Contractor shall install bentonite seal in the annular space above the sand pack. Add bentonite gradually to avoid bridging. Contractor shall measure the depth of the bentonite plug using a weighted tape. 14. Contractor shall hydrate the bentonite seal after placement with five (5) gallons of distilled or Engineer -approved water for each 2.5 vertical feet of seal. 15. Contractor shall allow the bentonite to hydrate according to manufacturer's specification or according to a field test demonstrating the time required for bentonite to hydrate. 16. Contractor shall pump neat cement through a tremie pipe filling the annular space from the top of the bentonite seal upward. The bottom of the tremie pipe shall be maintained below the top of the cement to prevent free fall and bridging. 17.Contractor shall try not to disturb the bentonite seal. 18. Contractor shall place neat cement in a single pour for wells up to 100 feet deep. For wells deeper than 100 feet, the Contractor shall pour neat cement in two pours, the second pour being at least 12 hours after the first pour. 19. Contractor shall pump neat cement with trimie pipe and continuously pull pipe to maintain 5 ft off set from the grout. 20. Contractor shall place neat cement in the boring up to the existing grade. Contractor shall allow neat cement to settle overnight. After neat cement settlement, Contractor shall place additional neat cement to a level as indicated in the construction figures. 21.Contractor shall install the well enclosure and do the surface completion only after the neat cement has hardened. E. Contractor shall record the following information on the Driller's Log: 1. Depth to water -bearing zones 2. Total depth of bore hole 3. Depth from ground surface to top and bottom of the well screen interval 4. Depth from ground surface to top of the sand pack interval 5. Depth from ground surface to top of the bentonite plug 6. Height above the ground surface of the top of the well casing 7. Height above the ground surface of the top of the steel protective casing. NC -Groundwater Monitoring Well Specifications 12/08/17 Page 7 of 13 San Joaquin County Public Works Dept Solid Waste Division