High concentrations of dissolved selenium have been detected in the lower Gunnison River basin including the Uncompahgre River basin. Butler and others (1991 and 1996) identified the highest concentrations of selenium in surface waters in areas that are irrigated on soils derived from Mancos Shale. In July 1997, the Colorado Water Quality Control Commission amended the classifications and numeric Standards for the Gunnison River Basin.
These amendments included new standards for dissolved selenium and the adoption of temporary modifications to selenium standards in three river segments and for one lake in the lower Gunnison River basin.
These sites are now included on the State of Colorado 303(d) list of impaired waters. The Gunnison Basin Selenium Task Force (STF) was formed to address the issue of exceedence of instream selenium standards in the basin. In addition, the Department of Interior National Irrigation Water Quality Program (NIWQP) is investigating the feasibility of remediating selenium sources in the lower Gunnison River basin.
OBJECTIVES:
Data characterizing selenium concentrations for streams tributary to the North Fork of the Gunnison River and the Gunnison River from the confluence of the North Fork of the Gunnison River near Grand Junction, Colorado. Tributaries basins on the east side of the Uncompahgre Valley.
- Characterize dissolved selenium loads at the outflow of about 15 to 20 selected tributaries, the North Fork of the Gunnison River, and the Gunnison River. Streamflow, dissolved selenium concentrations, and field measurements of pH, specific conductance, and water temperature will be collected and analyzed.
- Characterize selenium sources, with spatially intensive synoptic sampling on the east side of the Uncompahgre Valley. This characterization will be done in Loutzenhizer Arroyo, the unnamed tributary drainage southwest of Loutzenhizer Arroyo, and Cedar Creek.
- Characterize the spatial distribution of selenium in soils by coordinating tracer investigations with soil surveys being done in the study basins. This comprehensive data set that couples selenium sources with occurrence of selenium in the streams.
- To develop cumulative loading curves for dissolved selenium for each tracer investigation.
Below are publications associated with this project.
Characterization of salinity loads and selenium loads in the Smith Fork Creek region of the Lower Gunnison River Basin, western Colorado, 2008-2009
Concentrations and Loads of Selenium in Selected Tributaries to the Colorado River in the Grand Valley, Western Colorado, 2004-2006
Results of chemical analyses of soil, shale, and soil/shale extract from the Mancos Shale formation in the Gunnison Gorge National Conservation Area, southwestern Colorado, and at Hanksville, Utah
Characterization of selenium in the lower Gunnison River basin, Colorado, 1988-2000
Below are partners associated with this project.
- Overview
High concentrations of dissolved selenium have been detected in the lower Gunnison River basin including the Uncompahgre River basin. Butler and others (1991 and 1996) identified the highest concentrations of selenium in surface waters in areas that are irrigated on soils derived from Mancos Shale. In July 1997, the Colorado Water Quality Control Commission amended the classifications and numeric Standards for the Gunnison River Basin.
These amendments included new standards for dissolved selenium and the adoption of temporary modifications to selenium standards in three river segments and for one lake in the lower Gunnison River basin.
These sites are now included on the State of Colorado 303(d) list of impaired waters. The Gunnison Basin Selenium Task Force (STF) was formed to address the issue of exceedence of instream selenium standards in the basin. In addition, the Department of Interior National Irrigation Water Quality Program (NIWQP) is investigating the feasibility of remediating selenium sources in the lower Gunnison River basin.
OBJECTIVES:
Data characterizing selenium concentrations for streams tributary to the North Fork of the Gunnison River and the Gunnison River from the confluence of the North Fork of the Gunnison River near Grand Junction, Colorado. Tributaries basins on the east side of the Uncompahgre Valley.
- Characterize dissolved selenium loads at the outflow of about 15 to 20 selected tributaries, the North Fork of the Gunnison River, and the Gunnison River. Streamflow, dissolved selenium concentrations, and field measurements of pH, specific conductance, and water temperature will be collected and analyzed.
- Characterize selenium sources, with spatially intensive synoptic sampling on the east side of the Uncompahgre Valley. This characterization will be done in Loutzenhizer Arroyo, the unnamed tributary drainage southwest of Loutzenhizer Arroyo, and Cedar Creek.
- Characterize the spatial distribution of selenium in soils by coordinating tracer investigations with soil surveys being done in the study basins. This comprehensive data set that couples selenium sources with occurrence of selenium in the streams.
- To develop cumulative loading curves for dissolved selenium for each tracer investigation.
- Publications
Below are publications associated with this project.
Characterization of salinity loads and selenium loads in the Smith Fork Creek region of the Lower Gunnison River Basin, western Colorado, 2008-2009
The lower Gunnison River Basin of the Colorado River Basin has elevated salinity and selenium levels. The Colorado River Basin Salinity Control Act of June 24, 1974 (Public Law 93–320, amended by Public Law 98–569), authorized investigation of the Lower Gunnison Basin Unit Salinity Control Project by the U.S. Department of the Interior. The Bureau of Reclamation (Reclamation) and the Natural ResouConcentrations and Loads of Selenium in Selected Tributaries to the Colorado River in the Grand Valley, Western Colorado, 2004-2006
The reach of the Colorado River from the Gunnison River confluence to the Utah Border, and tributaries in the Grand Valley, are on the State of Colorado 303(d) list of impaired water bodies because the concentrations of dissolved selenium in these streams exceed the State of Colorado chronic standard of 4.6 micrograms per liter at the 85th percentile level. In response to concerns raised by a locaResults of chemical analyses of soil, shale, and soil/shale extract from the Mancos Shale formation in the Gunnison Gorge National Conservation Area, southwestern Colorado, and at Hanksville, Utah
Results of chemical and some isotopic analyses of soil, shale, and water extracts collected from the surface, trenches, and pits in the Mancos Shale are presented in this report. Most data are for sites on the Gunnison Gorge National Conservation Area (GGNCA) in southwestern Colorado. For comparison, data from a few sites from the Mancos landscape near Hanksville, Utah, are included. Twelve trenchCharacterization of selenium in the lower Gunnison River basin, Colorado, 1988-2000
Selenium concentrations in certain water bodies in the lower Gunnison River Basin, including the lower Gunnison River and lower Uncompahgre River, have exceeded the Colorado water-quality standard of 5 micrograms per liter for selenium. A task force was formed in 1998 that consists of various government agencies, private irrigation companies, and local residents to address the selenium concerns in - Partners
Below are partners associated with this project.