Effect of Groundwater Age and Recharge Source on Nitrate Concentrations in Domestic Wells in the San Joaquin Valley

Nitrate is one of the most abundant contaminants in groundwater globally, United States, and California (CA). We studied well construction information, water chemistry, stable isotopes, noble gases to understand how travel time recharge source mechanism control nitrate concentrations domestic wells San Joaquin Valley (SJV), CA, a large semiarid, irrigated agricultural region. Using nonparametric statistics, we find decreasing trend nitrates with depth. Samples collected from that are closer rivers show indications river recharge, either low temperature or δ18O signature, have lower than samples isotopic signatures indicating mixed local precipitation recharge. The curbing effect on similar for direct applied as irrigation. This suggests irrigation also has diluting reduces concentration found groundwater. conclusion supports idea flood-managed aquifer may be considered remediation when designing replenishment aquifers.