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. . Status of Grand Valley Remediation The NIWQP completed a diver- sion structure and pipeline at the Orchard Mesa Wildlife Area (OMWA) in September 2002 at a cost of about $82,000. This was the final step planned for reducing selenium hazards for endangered fish using the old river channels and back- ...!'~.. :lI1 waters within the OMWA. -'... The project provides a way l!>;.\OI of beneficially using water !fF from the OM4 Drain which has selenium concentrations ranging from 10 to 30 ppb. Additional acreage within the wildlife area can now be irrigated to enhance the available habitat. Irrigation will be done in a way which maximizes plant use and in- filtration of water into the soils. The return flows will become a diffuse discharge in a reach of the Colorado River which is relatively low - in selenium. Surface ponding of this water will be Inlet _ new QMWA ~. minimized to limit selenium p'(petlne~ exposure for waterfowl. We 'Nill continue annual mainenance in several previously con- structed flushing channels that dilute high selenium concentra- tions in the fish habitat. Elsewhere in the Grand Valley, three sites were evaluated for remediation; the Colorado River Wildlife Area (CRWA) Backwa- ter. a secondary channel at the mouth of Adobe Creek. and the south side of the Colorado River near the Panorama subdivision. Remediation is planned for the CRWA Backwater and for the secondary channel at the mouth of Adobe Creek. However, due to physical barriers limiting endangered fish access except during very high runoff, remediation is not being recom- mended at the Panorama site. ~... '" j 'n ~ :~Ji-Jf.'-'~ ,.. 41."~ . ....-_:I:',~~~_'JI,- ,.~~"." , - .,.t> ~ Page.' ~ ~ The CRWA Backwater is located directly across the river from the OMWA. A plan was recently selected which initially involves the excavation of a flushing channel to carry river water into this backwa- ter to dilute high selenium concen- trations resulting from inflows from Lewis Wash. the GJ3 Drain. and diffuse ground water. Construc- tion, of this estimated $20,000 project, is projected to be complete before the 2003 spring runoff. At the Adobe Creek site, about 8 miles west of Grand Junction, planning is nearing completion on a 950-footlong, 36-inch pipeline to convey high selenium irrigation return flows past a secondary channel of the Colorado River. The channel is important habitat for endangered fish. This project is scheduled for construction follow- ing runoff. in August 2003.