Modeling of groundwater flow and surface/groundwater interaction for upper Cienega Creek Basin

Abstract

The modular three-dimensional finite-difference groundwater flow model (MODFLOW) was used to study the hydrology of Upper Cienega Creek. The geological and hydrological characteristics of the basin indicate that the groundwater is contained in an unconfined aquifer. The study focuses on the interaction between groundwater and surface water in Upper Cienega Creek Basin and the surrounding basins (Sonoita and Bobocamari). The steady state analysis simulated the predevelopment conditions of the aquifer, and the transient state analysis, conducted between 1989 and 2002, predicted the response of the aquifer to future stresses. The location of pumpage and the volume of water pumped during the entire transient period resulted in a minimum reduction (1%) of the Cienega Creek stream flow. However, a drawdown of 200 ft located in Sonoita and Elgin area was predicted in the transient simulation. Capture calculations show that the reduction in evapotranspiratiou partially balanced the volume of water lost as result of pumping.