Monitoring Well Installation and Development
A permanent, Type II monitoring well is installed in each boring (Monitoring Well Construction Diagrams are available upon request). The Type II monitoring well is constructed using two-inch diameter, schedule 40, PVC casing with flush threaded couplings. The well screens may consist of PVC pipe with factory installed slots, which extends above and below the water table except in the case of deep wells. After the casing is installed, the annulus around the well screen is filled with clean graded sand to above the top of the screen.
Bentonite pellets are then placed on top of the sand and hydrated to form a seal. A cement-grout seal is then placed in the annulus from the bentonite seal up to the surface. The top of the PVC well heads are set in either a flush mounted traffic rated box a grade with an internal metal locking cover to provide security or a stand up steel casing with a water tight locking cover.
Following completion, the well is developed by hand bailing or pumping to remove fine-grained material and to improve the hydraulic connection with the formation. Ground water is allowed to stabilize for a day or more prior to purging the well of three casing volumes and collecting groundwater samples.