Mancos Watershed Functional Assessment

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The Reddert Ranch reach is located on the East Mancos River, where it joins the Middle Mancos River, and just as it emerges from a small canyon and enters the Mancos Valley proper. The reach is medium gradient. It is located on an old ranch, and was historically grazed but does not appear to be used at present. There is a road on the north side of the stream channel, mostly above the stream on the adjacent hillside. The reach is generally in good to excellent condition, with some exceptions. Nonchemical Water Quality was good, with the expected amount of algae, and with dense overhanging vegetation providing good solar shading. Hydrogeomorphology was generally very good, although the channel was incised more than what would be expected, suggesting that there have been high flow events in the past that have produced some downcutting. There appears to be little active erosion at present. There are no beavers in the assessment reach, but there is an active colony just across the road at the mouth of the Middle Mancos. It is likely these beavers will colonize the area in the near future, if not removed by humans. Fish/Aquatic Habitat was uniformly excellent, with the exception that there was no macroinvertebrate fauna found in the stream. In addition, no fish were observed during the assessment, despite the fact that this is excellent habitat, and that fish are found in the Middle Mancos where it joins the East Mancos. This indicates that there is probably something in the water that is killing the insects, and this should be examined in greater detail by more detailed chemical studies (see also note to West Mancos-Weber Diversion assessment, below). Riparian Vegetation and Terrestrial Wildlife Habitat was generally good to very good. There was a lack of shrub cover in much of the reach. This may be due to the heavy browsing levels that were observed on shrubs and small trees. There was little evidence of current livestock use, which suggests that most browsing at present is from mule deer and elk. Non-native herbaceous plant cover was high, but there were no non-native shrubs or trees found in the reach. 2. Middle Mancos River, Weber Reservoir Inlet Diversion Reach Location of beginning of reach: 12 S 0748322 East, 4143240 North Elevation: 2562 meters (8400 feet) References Photos: Figure 7. A, B Aerial Location Photo: Figure 8 Overall Score: 4.8 Individual Area Scores: Water Quality Mean Score: 4.8 Algal Growth: 5 Channel Shading: 5 Hydrogeomorphology Mean Score: 4.6 Floodplain Connection: 5 Vertical Bank Stability: 5 Hydraulic Habitat Diversity: 5 Riparian Area Soil Integrity: 4 Beaver Activity: 4 Fish/Aquatic Habitat Mean Score: 5.0 Pool Distribution: 5 Underbank Cover: 5 27