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RESULTS <br />INDIVIDUAL ASSESSMENT SITE DESCRIPTIONS <br />Survey Site Selection <br /> The specific locations where the RSRA surveys were conducted were chosen on the basis of <br />preliminary field reconnaissance, aerial overflight of the watershed, and in consultation with personnel of <br />the Mancos Conservation District. As discussed above, the initial field work indicated that the high <br />altitude sections of the tributaries of the main stem of Mancos River (the East, Middle and West Mancos <br />Rivers) showed only minor direct impacts from past or current human activities. These consisted <br />primarily of historic hard-rock mining activity on the East Mancos, and several small dirt roads along <br />limited sections of the stream in the Middle and West Mancos tributaries. In the upper canyon and plateau <br />region, there have been limited aspen harvests on the top of the plateaus. However, there were no obvious <br />visible impacts from these activities on the streams in the adjacent canyons since the sides of the canyons <br />in this section are very steep and have not been harvested. As is detailed below, however, there have been <br />channel and floodplain modifications resulting from construction of numerous water diversion structures <br />in both the Middle and West Mancos Rivers. <br /> As a result of these preliminary observations, we decided to concentrate the majority of the <br />assessments within the Mancos Valley itself. This part of the watershed is where a) there has been the <br />most past and present human activity that could potentially affect the stream-riparian ecosystem, b) the <br />benefit provided by the Mancos River to the human community from irrigated agriculture and other <br />factors such as tourism, recreation and quality of life, are the greatest, and c) any restoration program <br />undertaken in the future is likely to have the most direct and indirect positive impacts on the system. To <br />provide context for the assessments in the Valley, we also surveyed additional sites as follows. 1) To <br />determine the local impacts of major water diversions to feed the numerous water storage reservoirs in the <br />region, we assessed the functional condition of the West Mancos River above and below the Jackson <br />Gulch Reservoir inlet diversion and canal. 2) To examine the condition of the major tributaries of the <br />main Mancos River before they enter the Valley, we assessed: a) the East Mancos River where it joins the <br />Middle Mancos, and just upstream from the first agricultural (ranch) pastures, b) the Middle Mancos just <br />above the Weber Reservoir diversion, and c) the West Mancos in the canyon just above where it begins to <br />widen and enter the Valley. 3) We also examined two other primary tributaries that enter the Mancos <br />within the Valley proper, to determine if their input might affect the main stem of the River. These were <br />Chicken Creek, surveyed near where it joins the Mancos near the town of Mancos, and Mud Creek, where <br />we sampled an area of agricultural use west of the town of Mancos. 4) Finally, we assessed the condition <br />of the Mancos downstream of Mancos Valley. This survey was located within Mancos Canyon at the <br />mouth of Weber Canyon, and just above the border of Mesa Verde National Park and the Ute Mountain <br />Ute Indian Reservation. We were unable to conduct additional surveys further downstream on the Mancos <br />River within the Ute Mountain Reservation. The locations of the surveys are shown in Figure 4. <br />17 <br />