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Lorencito Canvon Mine - Aquatir Technics! ReDOrt • Periphyton Periphyton relative abundance data were collected on September 9 and 10, 1996. For each stream station, one sample was collected from the riffle habitat by scraping a 2 inZ area of rock substrate. Periphyton were not collected from the pond stations due to absence of suitable substrate. Periphyton were identified by Dr. Kugrens of Colorado State University. Several periphyton metrics were calculated including nondiatom dominant division, percent dominant nondiatom [axon, number of nondiatom taxa, number of diatom taxa, percent dominant diatom taxon, Shannon diversity index, eveness, pollution index, and siltation index. SECTION 3.0 -RESULTS AND DISCUSSION Fish Four species of fish were found within the analysis area (Table A-1). Two of the species found in Lorencito Canyon, flathead chubs (Hybopsis gracilus) and longnose dace (Rhinicthys cataractae), are flow dependant. This documents that these reaches (LC-1 and LC-4) of Lorencito Canyon have perennial flows. This is supported by monthly surface water monitoring data • reporting flow each month. However, as reported in the Surface Water Resources Technical Report, this montlily monitoring revealed that most of Lorencito Canyon is dry during much of the year. The fish populations and diversity at LC-1 and LC-4 indicate a healthy fishery, considering the intermittent nature of this stream. Additionally, all three species found in Lorencito Canyon are native (Woodling, 1989). Although not sampled during the aquatic biota inventory, fish were observed at a surface water monitoring station (spring SPAC-1) in Alamosa Canyon. Because this is an intermittent tributary to Lorencito Canyon, it is likely that the species occurring at this spring are the same species that were found in Lorencito Canyon. No fish species were found at the two Cow Canyon stock pond stations sampled. This was anticipated because both ponds were stagnant (no flow-through) and had limited macroinvertebrate populations as discussed below. Fish species found at the Purgatoire River stations were the same found in Lorencito Canyon with one additional species, brown trout. Brown trout were found at all three stations at fair population numbers with lengths ranging from 2 to 11 inches (Table A-1). The collection of young-of-the- year (2 inch) trout document natural reproduction in the system. aquatia176/Dttcmbcr 9, 1996 3