Origin of solutes in saline lakes and springs on the Southern High Plains of Texas and New Mexico

Analysis of hydraulic heads, calculation of pore volume flushing, and analysis of solute and isotopic chemistry strongly suggest that the solutes originate from the concentration by evaporation of runoff and potable shallow ground water that discharges from the High Plains aquifer. Chloride/bromide solute ratios, which are thought to be unaffected by mineral precipitation or sorption, average 160 in saline lakes and springs, close to an average for the High Plains aquifer (140), and are significantly different from the average deep-basin brines (680). Solute ratios of sodium/potassium, chloride/sulfate, and sulfur isotopes, although not conservative, also strongly support the hypothesis that solutes in the lakes were derived from shallow ground water from the High Plains aquifer and from overland runoff rather than from deep-basin brines.