Stream Depletion by Groundwater Pumping in Leaky Aquifers

Abstract

We present a simple approach to assess stream depletion by groundwater pumping in aquifers with leakage from an underlying source bed. The hydrogeological setting consists of a leaky aquifer that is hydraulically connected to a stream of shallow penetration. Under such conditions, the pumping rate is partially supported by the depletion of an adjacent stream. We quantify this phenomenon by deriving explicit analytical solutions that elucidate the interplay among the streambed, aquifer, aquitard, and well parameters. In particular, our solutions demonstrate how both hydraulic stream-aquifer connection and hydrostratigraphic conditions determine the possible fraction of the pumping rate supplied by the stream depletion. In leaky aquifers, this fraction decreases exponentially with the distance between a stream and a pumping well and is attenuated by a factor that depends on the streambed, aquifer, and aquitard parameters. The balance of pumping rate is supplied from recharge zone of the source bed.