See more from this Division: Topical Sessions
See more from this Session: Advances in Surface Water–Groundwater Interactions: Investigations of Rivers, Lakes, and Wetlands
Abstract:
Upper Colorado River salinity decreases downstream overall (8,430 to 1,540 mg/L TDS; 3,950 to 411 mg/L Cl; 1,500 to 566 mg/L SO4). Ratios of major ionic species vary systematically along flow and record base flow from sulfate- and carbonate-rich aquifers. Downstream increasing values for SO4/Cl of 0.32 to 1.3 record incremental input of dissolved Permian-evaporite sulfate. Increasing values for HCO3/SO4 of 0.23 to 0.9 through the most downstream reaches record base flow from Permian carbonate aquifers. A highly localized SO4/Cl-trend reversal marks enhanced chloride input near a small oilfield where water wells in the San Angelo aquifer show elevated chloride concentrations that are uncharacteristic of the aquifer elsewhere. Br/Cl and Na/Cl conservative mixing models indicate that stream hydrochemical characteristics in this location can be explained by a mixture of local oilfield brine with 98.6% to 99.5% local groundwater.
See more from this Division: Topical Sessions
See more from this Session: Advances in Surface Water–Groundwater Interactions: Investigations of Rivers, Lakes, and Wetlands