Monitoring Changes in Near-Well Hydraulic Conditions as a Means to Assess Aquifer Clogging

Abstract

To better understand and monitor the hydraulic effects caused by clogging near groundwater production wells, a study was conducted in the unconfined sand aquifer used by the City of North Battleford, Saskatchewan, Canada. Detailed investigations were carried out near one production well between the spring of 2007 and the fall of 2008. Results from four pumping tests conducted over this time period indicated no significant temporal changes in hydraulic conductivity within approximately 2 m of the pumping well. In contrast, long-term monitoring of hydraulic head differentials did reveal increases with time, and suggested that clogging began to accelerate within a radius of 1 m of the well after about one year of continuous pumping. Continuous monitoring of hydraulic head in pumping wells and nearby piezometers, combined with breakpoint analyses of head differentials and specific capacity tests, will be more effective than standard pumping tests for detecting temporal and spatial trends in aquifer and well screen clogging.