Intensive Ecological Assessment Objective: To describe biological communities (algae, invertebrates, and fish) and habitat conditions in selected environmental settings as a part of an integrated assessment of water quality in the Upper Colorado River Basin. Approach: Collect, sample, and measure conditions at each basic-fixed site. Tissue occurrence and distribution survey. Bed sediment occurrence and distribution survey. Ecological surveys—algae, invertebrate, and fish community. Habitat characterization.

The tissue occurrence and distribution survey was completed at the end of water year 1995 and beginning of water year 1996. The target taxa consisted of brown trout, white sucker, and bluehead sucker. White sucker and brown trout were selected in coordination with the National Target Taxa List (NTTL). Bluehead sucker was sampled at several sites because NTTL species were not present.

• Objectives:
1. Determine occurrence of contaminants in fish tissue.
   
2. Evaluate spatial distribution, land-use effects, and background conditions of contaminants.

• Approach:
  1. Samples were collected at 14 sites for tissue during low flow in the fall of 1995 (August-October). Twelve of the 14 sites were at basic fixed sites for the high intensity phase surface-water sampling efforts. The two remaining sites were selected to further assess the effects of mining and agriculture, two major land uses in the basin.
     
  2. Composites of whole fish were submitted to the USGS National Water Quality Laboratory (NWQL) for organics analysis and composites of livers were submitted for trace element analysis.
     
     
• Results:
  The results of the survey are presented in:
  
1. Stephens, V.C., and Deacon, J.R., 1998, Distribution and Concentrations of Selected Organochlorine Pesticides and PCB's in Bed Sediment and Whole-Body Fish in the Upper Colorado River Basin, 1995-96: U.S. Geological Survey Fact Sheet FS-167-97, 6 p.
2. Deacon, J.R., and Stephens, V.C., 1998, Trace Elements in Bed Sediment and Fish Liver at Selected Sites in the Upper Colorado River Basin, Colorado, 1995-96: U.S. Geological Survey Water-Resources Investigations Report 98-4124, 19 p.

The bed sediment occurrence and distribution survey was completed at the end of water year 1995 and the end of water year 1996.

• Objectives:
  1. Determine occurrence of contaminants in bed sediment.
     
  2. Evaluate spatial distribution, land-use effects, and background conditions of contaminants.
     
     
• Approach:
  1. During the fall of 1995, samples were collected at 16 sites for the analysis of trace elements and organics. Fourteen of the 16 sites were the basic fixed sites. The two remaining sites were selected to further assess the effects of mining and agriculture, two major land uses in the basin. Three additional sites were selected in agricultural areas and sampled only for organic analysis. Seven other sites were selected in mining areas, and samples were collected solely for the analysis of trace elements.
     
     Bed sediment samples were submitted to the NWQL for organic and trace element analysis and to the Cascade Volcano Observatory (CVO) for particle size analysis.
     
     
  2. To further refine the spatial distribution of trace-elements in bed sediment, 21 additional sites were sampled in mining areas during the fall of 1996. These samples were analyzed at a USGS research lab in Atlanta.

• Results:
  The results of the survey are presented in:
1. Deacon, J.R., and Driver, N.E., 1999, Distribution of Trace Elements in Streambed Sediment Associated with Mining Activities in the Upper Colorado River Basin, USA, 1995-96: Archives of Environmental Contamination and Toxicology, v. 37, p. 7-18.
   
2. Stephens, V.C., and Deacon, J.R., 1998, Distribution and Concentrations of Selected Organochlorine Pesticides and PCB's in Bed Sediment and Whole-Body Fish in the Upper Colorado River Basin, 1995-96: U.S. Geological Survey Fact Sheet FS-167-97, 6 p.
   
3. Deacon, J.R., and Stephens, V.C., 1998, Trace Elements in Bed Sediment and Fish Liver at Selected Sites in the Upper Colorado River Basin, Colorado, 1995-96: U.S. Geological Survey Water-Resources Investigations Report 98-4124, 19 p.
   

Algal, invertebrate, and fish community samples were collected during water years 1996 and 1997 at 15 sites in the basin. Fourteen of the sites were the basic fixed sites and one additional site was located on the Blue River downstream of French Gulch. Eleven of the 15 sites were also sampled during water year 1998.

• Objective:
  To assess the algal, invertebrate, and fish community structure at the basic fixed sites.

• Approach:
  1. Each sampling reach was selected to represent at least two types of geomorphic features characteristic of the stream segment.
     
  2. Each site or reach was sampled between mid July and October to insure maturity of biological communities and low flow.
     
  3. Quantitative samples of algae and invertebrates were collected at two instream habitat types and included a taxonomically richest-targeted habitat (RTH) and a depositional-targeted habitat (DTH).
     
  4. Fish communities were assessed through measurements of length and weight, numbers, and species identification. A collaborative effort was implemented with the U.S. Fish and Wildlife Service to assess the fish communities at selected sites.

• Results:
  The results of the surveys are presented in:
  
1. Mize, S.V., and Deacon, J.R., 2001, Algal Data from Selected Sites in the Upper Colorado River Basin, Colorado, Water Years 1996-97: U.S. Geological Survey Open-File Report 00-266, 61 p.
   
2. Deacon, J.R., Mize, S.V., and Spahr, N.E., 1999, Characterization of Selected Biological, Chemical, and Physical Conditions at Fixed Sites in the Upper Colorado River Basin, Colorado, 1995-98: U.S. Geological Survey Water-Resources Investigations Report 99-4181, 71 p.
   
3. Deacon, J.R., and Mize, S.V., 1997, Effects of Water Quality and Habitat on the Composition of Fish Communities in the Upper Colorado River Basin: U.S. Geological Survey Fact Sheet FS-122-97, 6 p.