Well‐Field Drawdowns Using Coupled Aquifer Model

Abstract

ABSTRACTWell‐field drawdowns in the Jay B. Starkey Wilderness Park in southwestern Pasco County, Florida were investigated using a coupled aquifer model developed by Motz (1978). In the model, water pumped from an underlying artesian aquifer is derived from leakage through an overlying confining bed. It is assumed that the leakage is derived from a reduction in evapotranspiration from the overlying water‐table aquifer. This process is represented by a coefficient (e) that is a linear representation of the rate at which evapotranspiration is reduced per unit of water‐table drawdown. This investigation in the Jay B. Starkey Wilderness Park provides an example of how the hydrologic coefficients in the coupled aquifer model can be calibrated from observed pumping and water‐level data and how water‐table and artesian aquifer drawdowns resulting from an increase in the pumping rate subsequently can be estimated. A value of e = 1.12 × 10−3 gpd/ft3 (1.76 × 10−9 sec−1) was obtained by matching calculated water‐table drawdowns to water‐table drawdowns attributed to the pumping effects of five production wells in the western part of the park. Five alternative plans for expanding the well field were examined, and it was recommended that the central and eastern parts of the park be developed as a well field.