WORK PLANS - Laserfiche WebLink

Home Browse Search

approximately ten to twenty feet in length and will be constructed out of 0.010-inch machine slotted screen. Well caps will consist of"j" plugs. Sand pack consisting of 10- 20 silica sand, or size appropriately for the screen slot size, will be placed opposite the well screen extending at least two feet above the well screen. At least three feet of bentonite chips will be used for well seals between the sand pack and the grout. A neat cement grout will be installed in the borehole from above the bentonite seal to ground surface. Once the neat cement is allowed to settle, more will be added until it is brought to the surface. All downhole material, with the exception of the neat cement, will be installed through the augers. As the annular material is installed, the augers will be pulled out of the borehole enough to allow the material to be placed,but not enough for the borehole to collapse. The neat cement grout will be installed using a tremmie pipe (if necessary) to ensure placement of the cement grout from the top of the bentonite seal to surface. A transitional seal consisting of 30 mesh sand may be placed between the sand pack and bentonite seal if necessary. Above ground surface monuments with lockable lids will be installed around each well for protection. Protective bollards will be installed around the well. San Joaquin County Division of Environmental Health will be notified prior to well completion for onsite inspection of the neat cement surface seal. The designs will meet the San Joaquin County and RWCQB requirements for monitoring well design and allow for long-term ground water monitoring use. A typical well diagram for the site is provided as Figure 6. Based upon expected ground water at 30 to 40 feet bgs and continuous sand layers within 60 feet of the surface, well depths are anticipated to range from 40 to 65 feet. Final depths will be determined based on field conditions encountered. In each case, the well screen will be placed in the first continuously monitorable zone encountered. The top of the well screen will be placed near the first encountered water table. Historical, seasonal and pumping water level fluctuations will be considered for screen placement. The drilling locations should all be in non-waste areas. Therefore, drill cuttings will not be containerized for disposal. Cuttings will be spread on the ground surface near each drill site. Woods Dairy March 1,2010 103-27 Monitoring Well Installation Plan 14 Revision 1