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' Elkhead Creek Aquatic Resource Report 6 Miller Ecological Consultants, December 5, 1996 t Physical/chemical data collected at each study site included; site location, length and width, delineation of macrohabitat types, macrohabitat mean depth, substrate, water temperature, ' dissolved oxygen, pH, conductivity, and air temperature. Stream discharge for each site was determined with the use of a Model 2100 Swoffer Flow Meter. General site attributes, such as gradient, instream structure, riparian zone and site specific limiting factors were recorded at t each site. These data in combination with the existing fish survey data are intended to provide an overview of the fish community structure within the study area. ' Habitat Mapping ' Habitat was mapped during fish surveys in September 1995 using a protocol developed by the Pike & San Isabel National Forest basinwide survey (Gallagher and Winters 1994). At each site the following data was recorded by ground crews: Rosgen channel type; stream gradient, ' habitat type and structural association, substrate type, bank erodibility, bank rock content, cover types, length, width and depth of all habitat units within the mapped section. At each site the area designated for habitat mapping was the same area used for fish surveys. Habitat data was ' later entered into a computer spreadsheet and summarized. ' Macroinvertebrate collection ' Benthic macroinvertebrate samples were collected from riffle habitat at each study site. Three replicate samples were taken at each collection site using a modified Hess stream bottom sampler. Samples were preserved in 70% ethanol and returned to the laboratory where ' specimens were identified to the lowest practical taxonomic level. Macroinvertebrate data was then entered into a computer spreadsheet for data analysis. Data analysis included a species list and calculated values for various indices including; Shannon-Weaver diversity and evenness, ' Family Biotic Index, total number of taxa, and macroinvertebrate densities. These data will be used, in addition to the fish data, to characterize general aquatic conditions. RESULTS AND DISCUSSION Fish Collections A total of 924 fish were collected from two sites on Elkhead Creek on the sampling dates 12-13 September, 1995. A total of 13 fish species, five native and eight non-native were captured. Table 1 provides a species list including common names and species codes. The data for individual specimens is presented in Appendix A.