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UU04P SeleniuJ Update , , \ \ J ~ . , '~["J'-..r .r.4...-::",\ 1.lJ-,-,,,,~.. "l - .' -....... /"1 .J For Colorado's Lower Gunnison River Basin & Grand Valley Prepared by the Department of the Interiors National Irrigation Water Quality Program Ne\vslelter No.2 October 1998 ,- , ,,- Remediation Priorities The purpose of the National Irrigation Water Quality Program (NIWQPI is to identify and address adverse impacts caused by contaminants in drainage from federally constructed irrigation projects. In western Colorado, selenium in drainage from the Uncompahgre (vicinity of Montrose, Delta and Olathe) and Grand Valley Projects is a concern. Elevated selenium levels are common in irrigation drainage throughout these areas and may be affecting a variety of fish and waterfowl. However, in order to respond to the issue with our limited resources, we must set priorities. The study team has adopted a remediation strategy that focuses on the primary concern of many -- impacts on endangered species. Along with the major economic, social and aesthetic benefits these large federal projects have generated, there is a responsibility to address their negative impacts. Also, unless actions are taken, the Endangered Species Act and Migratory Bird Treaty Act could create unwelcome consequences for us all. Therefore, the NIWQP is taking a proactive role and placing its highest priority on reducing potential selenium impacts to endangered Colorado River fish. Migratory waterfowl are an important, but secondary priority. Most of the concerns with endangered fish are focused around backwater or bottomland habitat along the Colorado River and with selenium loading to the mainstem Gunnison and Colorado Rivers, The NIWQP study team has begun to look for solutions to these problems. Planning Remediation One Grand Valley backwater site has been selected for remediation planning. The "Orchard Mesa wildlife area" is located along "OCT 2 ; f~;Ja I COlcrodo \\~~:J( Consef\1.1LCifl C"Qard < i , , , I ~ -'-. . , -.,. j/,/ I " \., the south bank of the Colorado River north of C Road between 30 and 31 Roads. Owned by the U.S. Government, the site contains several small backwater channels used by endangered fish during high runoff periods. Relatively warm and slow moving water with abundant food make such areas attractive to many native fish. Migratory waterfowl also frequent the area. NIWQP personnei have found irrigation drainage at this site with concentrations of 20 to 30 ppb (parts per billion) selenium entering backwater habitat where food organisms typically consumed by endangered fish are found with up to 18 ppm (parts per million) selenium. The levels of concern where adverse effects have been documented begin at 2 to 5 ppb in water and 3 ppm in food. The NIWQP's planning effort for the Orchard Mesa site will begin with a public open house and workshop on November 17 at the Mesa County Fairgrounds. The public and particularly Orchard Mesa residents are invited to attend to learn more about selenium and provide thoughts and ideas for fixing the problems. To obtain more information, please see the next page. Another planning effort is also beginning which involves drainage from the Uncompahgre Project, and its effects on the mainstem Gunnison and Colorado Rivers. Roughly 60-65% of the selenium load in the lower Gunnison River originates from this project area. 1 Studies are underway to better define the impacts this high selenium drainage is having on endangered fish in the mainstem rivers. There are also concerns about potential violations of state water quality standards for selenium and impacts to fish and wildlife using the lower Colorado River (Arizona, California,