Regional groundwater flow at the Nevada Test Site using stable isotopes and trace element chemistry

A deuterium-calibrated, discrete-state compartment (DSC) model was used to delineate regional groundwater flow at the Nevada Test Site (NTS) and vicinity. The DSC model compared well with the UGTA numerical groundwater flow model with a few exceptions. Underflow from Pahranagat Valley is not required to produce observed groundwater discharge at Ash Meadows. Half of the groundwater from Pahute Mesa flows southwest towards Oasis Valley and half flows south through Forty Mile Wash. Trace elements were unsuitable for DSC modeling because they are not chemically conservative.;Laboratory leaching experiments showed significant differences in trace element concentrations between carbonate and volcanic leachates. However, groundwater trace element concentrations were similar for samples throughout the regional NTS flow system regardless of aquifer rock type. The carbonate leachates compared well with groundwater from the carbonate and volcanic aquifers and the volcanic leachates compared well with local perched springs flowing through altered volcanic rock.