Using GIS and Multivariate Regressions to Model Salt and Selenium Loads in Regions of the Upper Colorado River Basin

Science Center Objects

Elevated loads of salt and selenium can impair the quality of water for both anthropogenic and natural uses. Understanding the environmental processes controlling how salt and selenium are introduced to streams is critical to managing and mitigating the effects of elevated loads. Dominant relations between salt and selenium loads and environmental characteristics can be established by using geospatial data.

The U.S. Geological Survey, in cooperation with the Bureau of Reclamation, investigated statistical relations between seasonal salt or selenium loads emanating from the Upper Colorado River Basin and geospatial data. Salt and selenium loads measured during the irrigation and nonirrigation seasons were related to geospatial variables for 168 subbasins within the Gunnison and Colorado River Basins. These geospatial variables represented subbasin characteristics of the physical environment, precipitation, geology, land use, and the irrigation network. 


  1. Model salt and selenium loading using quantified GIS information and regression analysis to simulate, track, and manage water quality in regions of the upper Colorado River and its tributaries.
  2. Locate and quantify areas where salt and selenium load reductions may be feasible and to estimate loading scenarios in regions of proposed development or transitional land use. Load reductions for salt and selenium will be modeled using remediation scenarios such as polyacrylamide applications in irrigation-delivery systems or improving septic-system placement and construction.