A Recharge Analysis of the Indian Wells Basin, California Using Geochemical Analysis of Tritium and Radiocarbon

Abstract

Quantifying recharge in arid watersheds, such as the Indian Wells Valley, CA, is critical for a reliable assessment of groundwater availability. In this study, lumped parameter models were coupled with tritium, radiocarbon, and helium data to generate groundwater ages. These ages were paired with (1) noble gas temperatures (NGTs) data to evaluate paleotemperature trends, and (2) well and aquifer parameters to calculate groundwater recharge rates. Age trends of NGTs reveal a complex climatic evolution within the Indian Wells Valley. Exponential trends between the point scale groundwater recharge rates and distance between the well and the mountain fronts of the basin translate to a mean mountain front recharge rate of 9.92 millimeters per year. These trends may be applicable in other arid settings where a lack of point scale data prevents a reliable estimation of recharge.