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NIWQP Project/Study Area—

Gunnison-Grand Valley

Location

This site was previously referred to as the Uncompahgre Project area and in the Grand Valley. It is located in west-central Colorado centered around Grand Junction where the Gunnison and Colorado rivers join. (Detail map pdf)

Background

The National Irrigation Water Quality Program's (NIWQP) work in the Gunnison-Grand Valley study area is aimed at remediating the effects of irrigation drainwater from Federal irrigation projects located in the upper Colorado River basin in western Colorado near the cities of Grand Junction and Montrose. These projects were constructed by the Bureau of Reclamation early in the 20th century and have been vital to the original settlement and economic development of the region.

Suspected selenium impacts to endangered razorback sucker and Colorado pikeminnow is the reason for NIWQP involvement in this area. The NIWQP is undertaking selenium remediation in an effort to avoid conflicts under Section 7 of the Endangered Species Act. Close coordination is maintained with the Upper Colorado River Endangered Fish Recovery Program which is working in the area to promote the re-establishment of self-sustaining populations of these fish.

Coordination and opportunities with the Grand Valley Selenium Task Force

The Grand Valley Selenium Task Force is a stakeholder group formed to address violations of state water-quality standards for selenium in impaired stream segments on Colorado ’s 303(d) list. This is "a group of private local, state and federal interests committed to finding ways to reduce selenium ... while maintaining the economic viability and lifestyle of the lower Gunnison River basin." The state facilitated the formation of this task force and one in the Grand Valley to hopefully develop Total Maximum Daily Load (TMDL) allocations and solutions at the local level. For more information, please see http://www.seleniumtaskforce.org/.The GRBSTF and the NIWQP worked jointly to identify and characterize selenium sources, evaluate remediation options, support demonstration projects and involve the public in the process.

NIWQP activities

NIWQP activities are divided between two primary areas of concern for the fish: 1) the mainstem of the Gunnison River (a tributary of the Colorado) and 2) Grand Valley backwater and bottomland fish habitat.

In the lower Gunnison River basin, NIWQP efforts are focused on reducing selenium loading from the irrigated areas that raise concentrations in the river to 6 parts per billion and in food organisms for endangered fish to 3 times the level of concern. Approximately 60% of the loading is the result of irrigation drainage from the Federal Uncompahgre Project in the vicinity of Montrose and Delta, Colorado.

One of the most successful of the demo projects occurred in the Montrose Arroyo drainage, just southeast of the city of Montrose. Here, the NIWQP joined with the Colorado River Basin Salinity Control Program and the Uncompahgre Valley Water Users Association to replace 8.5 miles of unlined, leaky irrigation ditches with 7.5 miles of buried PVC pipe. The results of the project were better than expected, reducing the selenium load from that basin by 27%. Other demonstrations are underway involving various task force participants and the NIWQP, including:

Spraying polyacrylamide (a.k.a. PAM) into irrigation ditches to reduce seepage
Lining ponds to reduce seepage,
Using phyto-remediation to remove selenium from the top soils
Developing Best Management Practices for non-agricultural sources (e.g., golf courses and septic tanks)

Each of the measures studied or implemented involve controlling the source of selenium mobilization with the goal of reducing the load in the lower Gunnison River and thus, selenium concentrations. Reducing the load in the Gunnison River will also help in the downstream reaches of the Colorado River where water quality standards for selenium are also exceeded.

In the Grand Valley, the NIWQP considered remediation at some 23 individual backwater/bottomland sites which are used by endangered fish that are receiving contaminated irrigation drainwater. At the Orchard Mesa Wildlife Area, the first site undertaken by the study team, remediation involved diluting the contaminated waters by constructing flushing channels and finding alternate uses for the irrigation drainage. This project was monitored for effectiveness. (See March 2004 Status Report (PDF))

Two sites were remediated by the NIWQP in the Grand Valley --- the Orchard Mesa Wildlife Area and the Colorado River Wildlife Area. Both of these sites are located along the Colorado River upstream of the Gunnison River confluence where mainstem selenium concentrations are still well below the standard. Planning and design activities have been completed for another site at the mouth of Adobe Creek, but when NIWQP funding shortfalls occurred, a decision was made to suspend the contracting process. The Panorama site was eliminated from further consideration.

Lessons Learned

The following briefly describes some of what has been learned to date that may be helpful during future study efforts:

The most important habitat for endangered fish is bottomlands and backwaters along the Colorado River which is often subject to high selenium surface and subsurface inflows from irrigation drainage and delivery system seepage.

The OMWA remediation planning process served as a pilot project for the NIWQP in the Grand Valley , and much was learned about remediation in backwaters and bottomlands including the following:

A. Source control is expensive and may not solve the problem. Source control measures reduce but may not totally eliminate deep percolation and seepage where selenium is mobilized in irrigated areas, unless the entire contributing area is converted to very efficient irrigation methods. If only a portion of the groundwater contributions are eliminated, most backwater sites will continue to receive sufficient selenium contaminated drainage to be problematic. Given the funding limitations of this program and likely availability of other funding, it’s more effective to utilize less costly dilution and diversion remedial measures in the backwater and bottomland habitat.

B. The Colorado River is a dynamic system . It does not generally make sense to spend significant dollars on “concrete” fixes within the flood plain, because the fixes may not be permanent. In the past, large discharge events have significantly changed river channels particularly in the 15-Mile Reach (Palisade to Gunnison River confluence). Some channels eventually fill with sediment and become part of the flood plain. It should be anticipated that this will continue. Some selenium trouble spots will come and go with natural river evolution. Long term maintenance of remediation improvements (flushing channels, diversions, etc.) will be needed to minimize selenium hazards for the fish at these sites.

C. Any fix will have to meet various stakeholder’s needs and criteria. The prime stakeholders include landowners, water users, the Recovery Program and in some cases, the Grand Valley Selenium Task Force.

D. Generally, the most cost effective fixes may involve drainage improvements or flushing. Various remediation measures should be tested over a range of typical site layouts and conditions. Common sense, minimizing expenditures, and preserving the environmental function of the sites should guide the selection of a plan.

Gunnison/Grand Valley Core Team Members (Colorado)

Mike Baker, BOR (Team Leader)
Paul von Guerard, USGS
Rick Krueger, FWS

Related Documents

Butler, D.L., Wright, W.G., Stewart, K.C., Osmundson, B.C., Krueger, R.P., and Crabtree, D.W., 1996, Detailed study of selenium and other constituents in water, bottom sediment, soil, alfalfa, and biota associated with irrigation drainage in the Uncompahgre Project Area and in the Grand Valley, west-central Colorado 1991-93: U.S. Geological Survey Water-Resources Investigations Report 96-4138, 136 p.

Butler, D.L., Wright, W.G., Hahn, D.A., Krueger, R.P., and Osmundson, B.C., 1994, Physical, chemical, and biological data for detailed study of irrigation drainage in the Uncompahgre Project Area and in the Grand Valley, West-Central Colorado, 1991-92: U.S. Geological Survey Open-File Report 94-110, 146 p, 1 pl.

Crock, J.G., Stewart, K.C., and Severson, R.C., 1994, Listing of geochemical data and assessment of variability for soils and alfalfa of the Uncompahgre Project Area, Colorado: U.S. Geological Survey Open-File Report 94-580, 83 p.

Stewart, K.C., Crock, J.G., and Severson, R.C., 1993, Chemical results and variability assessment of selected water-extractable constituents from soils of the Uncompahgre area, west-central Colorado: U.S. Geological Survey Open-File Report 93-507, 27 p.

Wright, W.G., and Butler, D.L., 1993, Distribution and mobilization of dissolved selenium in ground water of the irrigated Grand and Uncompahgre Valleys, western Colorado: in Allen, R.G., and Neale, C.M.U., eds., Management of irrigation and drainage systems: integrated perspectives: American Society of Civil Engineers, Proceedings of the 1993 National Conference on Irrigation and Drainage Engineering, Park City, Utah, July 21-23, 1993, p. 770-777.

Wright, W.G., Butler, D.L., Wolny, D.G. and Fukui, L.M., 1992, Factors affecting distribution of dissolved selenium in the Mancos shale and associated alluvium in the irrigated Grand and Uncompahgre Valleys, western Colorado: (abs.) in Abstracts of the Symposium on the Environmental Geochemistry of Sulfide Oxidation, American Chemical Society 204th National Meeting, Washington, D.C., 1992, paper No. 96.

Butler, D.L., Krueger, R.P., Omundson, B.C., Thompson, A.L., and McCall, S.K., 1991, Reconnaissance investigation of water quality, bottom sediment, and biota associated with irrigation drainage in the Gunnison and Uncompahgre River Basins and at Sweitzer Lake, west-central Colorado 1988-89: U.S. Geological Survey Water-Resources Investigations Report 91-4103, 99 p.

Butler, D.L., Osmundson, B.C., and McCall, S., 1989. Review of water quality, sediment, and biota associated with the Grand Valley Project, Colorado River basin, Colorado. U.S. Geological Survey, Grand Junction, CO.