Characterization of salinity loads and selenium loads in the Smith Fork Creek region of the Lower Gunnison River Basin, western Colorado, 2008-2009

• DOI: 10.3133/sir20145101
• Publication Date: 2014-07-24T22:05:19Z
• Authors: Rodney J. Richards; Joshua I. Linard; Christopher M. Hobza

The lower Gunnison River Basin of the Colorado has elevated salinity and selenium levels. Salinity Control Act June 24, 1974 (Public Law 93–320, amended by Public 98–569), authorized investigation Lower Unit Project U.S. Department Interior. Bureau Reclamation (Reclamation) Natural Resources Conservation Service are responsible for assessing implementing measures to reduce loading in Basin. Cost-sharing programs help farmers, ranchers, canal companies improve efficiency water delivery systems irrigation practices. (irrigation canals) have been identified as potential sources seepage, which can contribute loading. wants identify seepage from order maximize effectiveness various salinity-control methods, such polyacrylamide lining piping canals programs. Geological Survey, cooperation with Reclamation, developed a study characterize seven subbasins Smith Fork Creek region where control efforts be maximized Total loads ranged 27.9±19.1 tons per year (t/yr) 87,500±80,500 t/yr. four natural subbasins—BkKm, RCG1, RCG2, SF1—had total t/yr, 371±248 2,180±1,590 4,200±2,720 respectively. agriculturally influenced sites had that 7,580±6,900 t/yr AL1, B1, CK1, SF2, SF3 were t/yr; 28,300±26,700 48,700±36,100 87,500±80,900 52,200±31,800 agricultural load was separated into three components: tail water, deep percolation, seepage. Annual tail-water 48.0 2,750 region. largest subbasin SF3, lowest R1. remaining subbasins—AL1, SF2—had 285 180 333 1,700 percolation component 3,300 AL1 51,800 SF2. Subbasins R1, 4,940 15,200 21,200 23,600 1,100 15,300 CK1. 6,610 3,890 9,430 12,100 Four subbasins—RCG1, SF1, BkKm—were used calculate yields subbasins. appropriate yield applied corresponding number acres resulted each subbasin. annual Dakota Sandstone Burro Canyon Formation, Mancos Shale, crystalline geologies 0.217 acre (t/acre), 0.113 t/acre, 0.151 Three little no based on measured data calculated loads. RCG1 RCG2 surface-water 0.106±0.024 pounds (lb) 0.00 lb, Subbasin BkKm did not an estimated because lack any water-quality samples during period. designated site CK1 highest 135±38.7 next decreasing R1 69.6±28.4 56.5±23.8 30.5±16.6 26.8±6.95 15.6±27.7