Beginning in the Spring of 1998, the basement of Orradre Library on the Santa Clara University campus was flooded by groundwater seeping in through cracks in the floors and lower walls.  An initial feasibility study found that regional shallow groundwater levels had risen 30 feet in the past ten years.
Seepage into the building basement occurred from upward movement of groundwater from an underlying aquifer between 35 and 45 feet below ground surface. Continuous pumping of wells completed in the shallow aquifer was proposed to lower the water table and drain the soils beneath the basement of the building.
Initially, clustered observation wells were installed at the four corners of the 200-foot square building.  Observation wells were completed in clayey soils at the water table depth of 15 feet and in the shallow aquifer at a depth of 35 feet.  In addition, a test well was installed in the shallow aquifer.
Static water levels were monitored for a period of time and then the test well was pumped for one week.  Water level responses in the observation wells confirmed that dewatering was feasible and three production dewatering wells were proposed.
		A production well assembly is shown partially assembled on pipe stands next to the drilling rig. Due to potentially corrosive and encrusting groundwater, production wells were constructed of Type 316 stainless steel continuous-slot well screen coupled to PVC blank well casing.
A well assembly is raised up the drilling rig mast prior to installation in the borehole.
	Once the well assembly is placed in the borehole, a sand filter pack is poured into the borehole around the well screen.  The well screen slot openings are sized to keep out most of the sand filter pack.  The filter pack is in turn sized to filter out most of the aquifer formation. Following the addition of the sand filter pack, the remainder of the borehole up to the ground surface will be filled with a cement grout seal to prevent surface water from draining into the well.
The completed wells were developed by swabbing and bailing.  Development cleans out residual drilling muds and formation fines in the sand filter pack and near the borehole wall, improving the yield. Within three days of the start of pumping, the library basement dried out and has remained dry since.  Total discharge from the three wells is about 110 gallons per minute.
		Variable speed well pumps are operated by a programmable logic controller so that a constant water level is maintained in each well.  An electronic monitoring system logs critical data for remote or local retrieval and automatically calls system administrators in the event of a failure or abnormal condition.