Impact of hydrological alterations on river-groundwater exchange and water quality in a semi-arid area: Nueces River, Texas

摘要: There is a lack of understanding and methods for assessing the effects anthropogenic disruptions, (i.e. river fragmentation due to dam construction) on extent degree groundwater-surface water interaction geochemical processes affecting quality in semi-arid, coastal catchments. This study applied novel combination electrical resistivity tomography (ERT) elemental isotope geochemistry disturbed by extended drought periodic flooding operation multiple dams. Geochemical analyses show that saltwater barrier causes an increase salinity surface downstream as result limited freshwater inflows, strong evaporation shallow groundwater mostly stagnant water, not intrusion tidal flooding. Discharge from bank storage dominant (~84%) fragment its contribution could levels within hyporheic zone water. When go up upstream releases temporarily displaces high trapped underlying aquifer. modeling shows higher distant deeper (~40%) lower discharge (~13%) through zone. Recharge source salt both portions but below dam. Continuous ERT imaging bed complements findings indicate while lithologically similar, dam, aquifer affected salinization fresher saturates fragment. The relative flows or discharge) related control changes streamwater chemistry likely impact interpretation seasonal trends.