Storage Basin Volume and Drainage Basin Dynamics: Camas Prairie, South‐Central Idaho

Abstract

ABSTRACTA recent tectonic model and subsequent gravity survey and basement modeling have raised questions concerning the size of the Camas Prairie ground‐water storage basin and the hydrodynamic properties of the Camas Creek drainage basin. This paper addresses storage basin dimensions using an anomalous mass determination from a plot of residual gravity, and presents estimates of recharge and underflow from a mass‐balance study. Underflow may transport much of the water [2·73 (105) acre‐feet/yr] (ac‐ft/yr) calculated as residual in the mass‐balance study, and transport is from the Camas Prairie storage basin south to the Snake Plain Aquifer via permeable strata in the Mount Bennett Hills surface drainage divide. Results of the anomalous mass study suggest that the volume of ground water stored in the Camas Prairie basin is 39 (106) ac‐ft, considerably greater than previously estimated. Similarly, recharge to the Camas Prairie basin is estimated at over 7(105) ac‐ft/yr, one order of magnitude greater than earlier estimates.