Upper Colorado River Basin: Monitoring sites and water chemistry data used to develop a specific conductance - salinity proxy model

Salinity levels in streams and tributaries of the Colorado River Basin have been a major concern for years. Recently, the United States Geological Survey’s (USGS) Next Generation Water Observing System (NGWOS) program expanded stream monitoring networks including the number of sites where continuous (15-minute) specific conductance is measured in the Colorado River Headwaters and Gunnison River subbasins located east of the Colorado-Utah state line (hereafter, UCOL). Salinity and total dissolved solids (TDS) can be estimated using specific conductance and water type as a proxy (McCleskey et al., 2023); thus, the UCOL is an ideal basin to apply the proxy. The data presented in this data release, including monitoring site information and water chemistry data, were used to develop a specific conductance and water type proxy model for salinity and TDS for sixty-six USGS monitoring sites in the UCOL. The monitoring site information and water-quality data for the sample sites in the UCOL were retrieved from the Water Quality Portal (Read et al., 2017) using the USGS dataRetrieval R package (De Cicco et al., 2018). The dataset contains 80,206 discrete water analyses collected between 1990 and 2023. The water chemistry data includes the concentrations of calcium, magnesium, sodium, potassium, chloride, sulfate, fluoride, nitrate, iron, boron, aluminum, alkalinity, and silica. A subset of this data includes 4,588 samples all of which have at least the concentrations of calcium, magnesium, sodium, potassium, chloride, and sulfate reported, a charge balance < ±10%, and a specific conductance imbalance < ±15%, unless the specific conductance was less than 100 µS/cm in which case the specific conductance difference was < ± 10 µS/cm. Finally, salinity and TDS were calculated for the discrete samples in the subset (McCleskey et al., 2023).

References

De Cicco, L.A., Hirsch, R.M., Lorenz, D. and Watkins, W.D., 2018. dataRetrieval: R packages for discovering and retrieving water data available from Federal hydrologic web services, doi:10.5066/P9X4L3GE.

McCleskey, R.B., Cravotta, C.A., Miller, M.P., Tillman, F.D., Stackelberg, P., Knierim, K.J. and Wise, D., 2023. Salinity and total dissolved solids measurements for natural waters: An overview and a new salinity method based on specific conductance and water type. Applied Geochemistry, 154.

Read, E.K., Carr, L., De Cicco, L., Dugan, H.A., Hanson, P.C., Hart, J.A., Kreft, J., Read, J.S. and Winslow, L.A., 2017. Water quality data for national-scale aquatic research: The Water Quality Portal. Water Resources Research, 53(2): 1735-1745