Laserfiche WebLink
DRAFT DRAFT DRAFT <br />fine sediment loads from tributary watersheds draining Disappointment and Big <br />Gypsum Valleys and vegetation that aggressively colonizes fresh sediment <br />(mainly tamarisk, willow, and phragmites) has narrowed and entrenched the <br />active channel through alluvial portions of Reach 4. Surveys indicate a <br />prevalence of non-native aquatic species. Only one brown trout was sampled in <br />five years of surveys in the Big Gypsum Valley, and this reach is not considered <br />a cold water fishery. <br />Reach 5 Big Gypsum Valley to Wild Steer Canyon (42 miles) -Reach 5 <br />Slickrock Canyon) has a low gradient, high sinuosity, and is confined by steep <br />canyon walls. The river through most of this reach is only accessed by hiking in <br />or floating the river. Few to no trout are found in this part of the river and salinity <br />levels rise downstream. A fairly distinct change in riparian vegetation occurs just <br />upstream of Coyote Wash, where native communities of box elder, New Mexico <br />privet and willow change to atamarisk-dominated riparian area. A few scattered <br />spring-fed cottonwoods occur in side tributaries (e.g., Bull Canyon), but they are <br />not a component of the main channel riparian community. A BLM Wilderness <br />Study Area surrounds this reach of the river. The reach has not been sampled <br />for native fish since 1992, when a relatively complete assemblage of native fish <br />was identified. <br />Reach 6 Wild Steer Canyon to San Miguel River (12 miles to Saucer <br />Basin) Flat and wide with high concentrations of salt, this area is dominated by <br />tamarisk. Large stands of very old cottonwoods still exist, disconnected from <br />channel dynamics, and there is little or no evidence of regeneration. A salt <br />dome beneath the Paradox Valley introduces high salt loads into surface water <br />through this reach. High salinity, fine sediment accumulations, and lack of <br />channel structure result in poor habitat quality for native fish through the <br />Paradox Valley. The last few miles enter a broad but confined canyon, where <br />increasing gradient and channel structure improve instream habitat potential <br />above the confluence with the San Miguel River. A county dirt road allows <br />access throughout the canyon portion of Reach 6. <br />D. Core Science: Discipline Summaries <br />SAME DISCUSSION ITEM: TO WHAT EXTENT ARE `DATA/CONCLUS/ONS' <br />APPROPRIATE FOR THE DISCIPLINE SUMMARIES?] <br />To evaluate the various strategies and determine the preferred alternatives, the <br />Dialogue has convened a Core Science Team (CST) with technical expertise in <br />several disciplines. This team was established in early February of 2005 to study <br />and ultimately integrate four primary areas of investigation; Native warm water <br />fisheries, Cold water fisheries, Geomorphology and Riparian Ecology..." <br />[Core Science Report, page 1 ] <br />Below, the four disciplines that frame the Core Science Report are briefly defined <br />as they will be used throughout the Correlation Report: Geomorphology, Riparian <br />Ecology, Cold Water Fishery and Warm Water Fishery: <br />9/5/06 1 ~ <br />