HYBRID: a wellhead protection delineation method for aquifers of limited extent

Abstract

Delineating wellhead protection areas around existing wells can be difficult due to the complexity of the architecture and material that constitutes the aquifer. For example, the unconsolidated aquifers of the St. Lawrence Lowland often have a stripped shape, and simple analytical methods alone are usually inappropriate to define the wellhead protection areas. In this context, a HYBRID method was developed. This proposed method uses field observations and/or simple analytical methods to delineate the upgradient and downgradient boundaries of the wellhead protection areas.Asimple water balance between the aquifer recharge rate and the pumping well discharge rate serve to constrain the size of the elliptic wellhead protection areas. Not only is the method useful for the delineation of the zone of contribution, but also for the zone of travel.