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<br />
<br />Physical, Chemical, and Biological Data for Detailed
<br />Study of Irrigation Drainage in the Uncompahgre
<br />Project Area and in the Grand Valley,
<br />West-Central Colorado, 1991-92
<br />
<br />ByDavid L. Butler, Winfield G. Wright, Dorothy A. Hahn, Richard P. Krueger, and
<br />Barbara Campbell Osmundson
<br />
<br />Abstract
<br />
<br />Because of concerns about potential effects
<br />of irrigation drainage on fish and wildlife
<br />resources and on human health, the U,S. Depart-
<br />ment of the Interior initiated a program in 1985 to
<br />assess water-quality problems associated with
<br />Federal irrigation projects in the Western United
<br />States. Physical, chemical, and biological data
<br />were collected for a detailed study of irrigation
<br />drainage in the Uncompahgre Project area and in
<br />the Grand Valley, west-central Colorado, during
<br />1991-92.
<br />This report lists onsite measurements and
<br />concentrations of major constituents, trace ele-
<br />ments, and stable isotopes for surface-water- and
<br />ground-water-sampling sites in the Uncompahgre
<br />Project area and in the Grand Valley. Insecticide
<br />data collected at selected surface-water sites in the
<br />Grand Valley in 1991 are presented. Ranges of
<br />specific-conductance measurements and dis-
<br />solved-oxygen concentrations for selected wells in
<br />both areas and a daily record of water-level alti-
<br />tude and specific conductance for a well in the
<br />Grand Valley are presented. The report also pre-
<br />sents historical water-level and dissolved-solids
<br />data collected by the U.S. Bureau of Reclamation
<br />for two wells in the Grand Valley.
<br />Concentrations of trace elements, major
<br />constituents, total carbon, and organic carbon in
<br />bottom-sediment. bedrock, and aquifer-sediment
<br />samples are listed in the report. Also presented are
<br />semiquantitative data on clay and bulk mineralogy
<br />of various types of samples from the Mancos
<br />Shale, selenium-speciation data for selected water
<br />and bottom-sediment samples, and selected aqui-
<br />fer-test results.
<br />Biological samples collected in the
<br />Uncompahgre Project area and in the Grand Valley
<br />
<br />included aquatic plants, aquatic invertebrates, fish,
<br />birds, and bird eggs. The report lists concentra-
<br />tions of trace elements in biological samples col-
<br />lected in 1991-92. A limited number of biological
<br />samples were analyzed for pesticides, PCB's, and
<br />polycyclic aromatic hydrocarbons.
<br />
<br />INTRODUCTION
<br />
<br />Large concentrations of selenium have been
<br />detected in irrigation drain water in the San Joaquin
<br />Valley in California, In 1983, incidences of mortality,
<br />birth defects, and reproductive failure in waterfowl at
<br />the Kesterson National Wildlife Refuge in the western
<br />San Joaquin Valley were reported by the U.S. Fish and
<br />Wildlife Service. Irrigation drain water was impounded
<br />at the refuge, Because of the concern that problems
<br />related to selenium or other trace inorganic or organic
<br />constituents in irrigation drainage might not be limited
<br />to the Kesterson area, the U.S. Department of the Inte-
<br />rior (DOl) began a program in 1985 to detennine
<br />whether irrigation-drainage problems existed at other
<br />DOl constructed or managed irrigation projects,
<br />national wildlife refuges, or other wetland areas for
<br />which the DOl has responsibility, The program has
<br />evolved to include five phases (Deason, 1986): (I) Site
<br />identification, (2) reconnaissance investigations,
<br />(3) detailed studies, (4) planning, and (5) remediation,
<br />Activities in the first three phases are conducted by
<br />study teams consisting of scientists from the U.S.
<br />Geological Survey (USGS), the U,S, Fish and Wildlife
<br />Service (FWS), the U.S. Bureau of Reclamation
<br />(BaR), and the U,S. Bureau of Indian Affairs (BIA),
<br />A USGS scientist heads each study team. Activities in
<br />phases 4 and 5 are done by the BaR.
<br />About 600 irrigation projects and major wildlife
<br />resource areas have been constructed or are managed
<br />by DOl bureaus in 17 Western States. Reconnaissance
<br />investigations are designed to detennine whether irri-
<br />gation drainage (I) has caused or has the potential to
<br />cause significant hannful effects on human health or on
<br />
<br />Abstract
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