WATERSHED-BASED TRADING CONCEPTS IN THE COLORADO RIVER BASIN – INNOVATIVE APPROACHES TO MULTIPLE WATER QUALITY AND ENVIRONMENTAL BENEFITS

Nonpoint sources are logical targets for future pollution reduction efforts using water quality incentives like pollutant trading. In conjunction with the City of Grand Junction, Colorado, URS Corporation (URS) obtained grant funding from U.S. EPA to demonstrate a “Selenium Trading Program Framework” (Trading Program) within the Lower Colorado River Basin. Selenium is a significant water quality issue, as reflected on the Colorado 303(d) list for Colorado River Basin stream segments. The Trading Program provides an innovative mechanism for multiple water quality and environmental benefits in the area, including;Identifying, selecting, and piloting effective selenium controls to address the selenium TMDL,Reducing nonpoint source loading from agricultural and urban sources,Enhancing the habitat for aquatic life in the Lower Colorado River and facilitating endangered fish species recovery,Exploring opportunities for cross pollutant trading,Developing a trading program that encourages “from the grassroots up” approaches,Maximizing trading partner flexibility (i.e. between point and nonpoint sources; nonpoint and nonpoint sources; nonpoint and point sources), andImproving the chemical, physical and biological integrity of the Lower Colorado River.This unique trading demonstration project tests and applies trading tools and approaches geared towards holistic environmental benefits and effective reduction of selenium from agricultural and urban sources. Other water quality benefits inherent to the Trading Program include a reduction of nutrient and sediment loads.Features of the Trading Program in the Lower Colorado River Basin (Colorado) target the following critical water quality and environmental issues:High selenium concentrations are a serious concern in the Lower Colorado River Basin, Colorado. The selenium is found naturally in the Mancos Shale and leaches into the system as a result of irrigation return flow and deep percolation. The Colorado River, as well as a number of tributary streams, exceed the water quality standard for selenium.Habitat for four threatened and endangered fish species is located along the Colorado River within the study area. Recovery actions proposed by the U.S. Fish and Wildlife Service are important to improving habitat for these species in the Colorado River. Opportunities for facilitating implementation of these actions through the Trading Program are being investigated.Agricultural nonpoint sources can be managed to reduce selenium loads. The Grand Valley of the Lower Colorado River Basin contains some of Colorado's richest agricultural lands, ideally suited for the production of fruits, vegetables, and grains. A variety of selenium control options are being analyzed and pilot-tested with watershed stakeholders to identify cost-effective and socially acceptable pollutant reduction mechanisms under the Trading Program.Selenium and nutrient loads from Individual Sewer Disposal Systems (ISDS) can be managed. A potential source of selenium and nutrient loads to alluvial groundwater and surface water is ISDS leachate. Municipalities in the region, such as the City of Grand Junction, are well suited to evaluate the costs and water quality benefits of an ISDS conversion program in key areas of selenium contribution.Stormwater is a potential contributor to selenium loads in the Lower Colorado River Basin. Pollutant reduction facilities that target selenium removal from stormwater discharges may result in water quality benefits conducive to the Trading Program.Wastewater treatment facilities (WWTFs) are challenged to meet wasteload allocations and stringent effluent concentration limits. The aquatic life (chronic) standard for selenium is 5 ∝g/L. Due to the selenium issues in the basin, WWTFs may be required to use this selenium standard to come up with water quality based effluent limits.