Drawdown, Velocity, Storage, and Capture Response Functions for Multiaquifer Systems

Response functions for drawdown, velocity, storage losses, and capture describe the spatial and temporal reaction of an aquifer to a unit pumping stress. This paper extends the use of response functions to the notion of capture for multilayered aquifer systems. Capture describes the pumping‐induced quantity of water gained by the aquifer from internal or boundary sources. Internal sources include rivers and hydraulically connected aquifers. Boundary sources include constant head and head‐dependent boundaries. Although response functions are defined only for linear systems, a methodology is demonstrated for implementing response functions in cases of nonlinear capture. The value of response functions lies in their utility as hydrologic constraints in management optimization models. An example demonstrates the use of separable programming to determine the nonlinear effects of drawdown below the bottom of a streambed.