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I. ., I. \ . I I I I . . I I . I . I 1,- t I 3 a blank sample were collected at one site chosen randomly each year during the biologica' sampling. The high school collected blanks and duplicate samples every fifth sampling event during the year. The blank and duplicate samples were for field quality control and assurance, 2.2 Macroinvertebrates Macroinvertebrates were collected using a kick screen method prior to electrofishing at each site. Two samples from two different riffle areas were collected at each site. For each sample, one person held the net in a riffle area while a second individual dislodged material from the stream sediment upstream of the net. Dislodged materials, including macroinvertebrates, were swept downstream into the net. The net was taken to the shore, and macroinvertebrates were picked out with forceps and placed into 70% ethyl alcohol solution. Organisms were picked from each net for a time period equal to 60 minutes. If four people picked a sample, then each worked for 15 minutes, The two separate samples were then combined, The samples were taken to the laboratory for identification to the lowest possible taxonomic level. A voucher collection is maintained in the Denver DOW Habitat Section, ) 2.3 Fish Fish were collected using a pulsed, direct- current electrofishing bank unit, except at the two most upstream headwater Fourmile Creek sites in 1995, where a backpack electrofishing unit was used. Two collection passes were made at each sampling site (except the most upstream Fourmile Creek 1995 site when less than ten fish were collected on the first pass), Fish were identified to species, weighed to the nearest gram, measured for total length to the nearest millimeter and returned to the water. Population estimates were calculated using the Seber LeCren formula, Electrofishing techniques probably do not sample fish less than 100 mm total length very effectively, As a result, longnose dace population estimates (and estimates for other minnow species) were not precise. Population estimates for minnows and suckers in Fourmile Creek, such as the longnose .dace and wb!le sucker, were calculated primarily to indicate trends. Biomass estimates were calculated by multiplying the average weight of a species collected at each site by the Seber LeCren population estimate for that species. ,... .-.-...,.... .- .. -'-'. 3.0 Results 3.1 Water Quality 3.1.1 Fourmile Creek Concentrations of most parameters were the lowest at the farthest upstream sites !' and increased downstream, typical of Rocky Mountain streams (Table 2), The exceptions included temperature and dissolved and total metals. Temperature values are a function