Relations of specific conductance to streamflow and selected water-quality characteristics of the Arkansas River basin, Colorado

Areal, seasonal, and long-term variations in the specific conductance of surface and groundwater in the Arkansas River basin of Colorado were evaluated and relations of specific conductance to stream-flow and to concentrations of dissolved solids and major ions were determined as part of an effort to develop a comprehensive hydrologic model of the basin. Mean specific conductance of surface and groundwater was smallest in the upper basin and increased downstream. Smallest mean specific conductance occurred during summer runoff, and largest mean specific conductance occurred during spring and fall low flows. Trends in specific conductance occurred at 18 of 31 surface-water stations and in flow-adjusted specific conductance at 14 of 24 surface-water stations. Logarithmic relations of specific conductance to streamflow were determined for 69 stations. Significant seasonal differences in the relations illustrate the effect of basin characteristics on the relation of specific conductance to streamflow. Relations of specific conductance to dissolved-solids concentration were determined for 28 surface-water stations and for groundwater in alluvial aquifers along the Arkansas River. Relations of specific conductance to concentrations of major ions were determined for 26 surface-water stations and for groundwater in alluvial aquifers along the Arkansas River. (USGS)