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The Dolores River riparian community has been heavily impacted by invasion of non-native <br /> tamarisk. Depending upon the location, the tamarisk component of the riparian community can <br /> range from 10 to 80% of vegetation cover. However, there are still extensive occurrences of <br /> native species, including Rio Grande Cottonwood, Narrow-leaf Cottonwood, Box Elder, Coyote <br /> Willow, Skunkbrush, and New Mexico Privet. In many locations, tamarisk dominates the zone <br /> immediately adjacent to the river channel and native species dominate the first terrace that is <br /> slightly elevated above the river channel. Even with the tamarisk impact, the river banks are in <br /> stable condition and excessive erosion does not appear to be impacting the aquatic community. <br /> As mentioned previously, the Dolores River Restoration Partnership is making a major <br /> investment in treating the invasive species along the river. The Partnership's objective is to <br /> increase the vigor and extent of native riparian species, including Rio Grande Cottonwood, <br /> Narrow-leaf Cottonwood, Box Elder, Coyote Willow, New Mexico Privet, and Skunkbrush. For <br /> the river corridor to successfully transition back to a vegetation community dominated by native <br /> species, a supporting hydrologic regime will be required that provides periodic flooding and <br /> maintains groundwater levels within the root zone of the riparian community. <br /> While the proposed instream flow water right doesn't protect the highest flood flows, BLM and <br /> CPW believe that the proposed seasonal variations in flow rates will provide good support for <br /> groundwater levels in near-stream alluvial deposits. This support is accomplished by protecting <br /> stream flow during the snowmelt runoff period, the flows that recharge near-stream alluvial <br /> deposits. In addition, by protecting base flows during seasonally dry periods, groundwater levels <br /> in near-stream alluvial deposits can be maintained during high temperature and high <br /> evapotranspiration periods. Maintenance of groundwater levels in near-stream alluvial deposits <br /> during both periods will sustain the health and vigor of the riparian community. <br />