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. Biodiversity. Healthy, flowing rivers support species biodiversity. Degraded stream habitats have contributed to fish and other freshwater aquatic species becoming the most endangered species in the United States. The Nature Conser- vancy reports that 39% of freshwater fish species are at risk, in comparison to 1"7% of mammals and 15% of birds. . Water Quality. Clean water benefits both instream and out-of-stream users. Water quality suffers from reductions in water quantity. Too little water in a stream means that pollutants from mining, agriculture, industry, cities, and even natu- ral sources are more concentrated, and therefore more problematic. Low flows can also increase sediment deposition, which can suffocate fish eggs and harm insect populations that are key parts of the aquatic food chain. . Water Temperature. Unnaturally low flows in a stream can lead to unnaturally high water temperature, harming or even killing the aquatic species that inhabit the stream. This prob- lem is further exacerbated by the discharge of' heated water into the stream, for example, from cooling towers at power plants. _:__~:,...._ ",ry~S::"~~:~::"""''''_'''~'_ ,"':' , "" The Snake River in Summit County szifJers from serious}yater qliality degradation from years of mine' tailing runoff. II La Plata River , , The La Plata River in sa.uthwestern Colorado supports a Colorado River native fish community, Due to habitat degradation and flow depletions, the portion of the river maintaining these native fish species has been relegated to an approximate five mile stretch of river just above the Colorado/New Mexico State line, Other sections of the La Plata Ri'ver downstream from Hesperus are seasonally dried up due to irrigation diversions, as illustrated in the photo on the cover, Within the reach near the state line a small, isolated, but seemingly healthy population of roundtail chubs exists within these unique, limited habitats, Other native fish inhabiting this section of river include the flannel mouth and bluehead sucker, mottled sculpin and speckled dace. An increase or change in water rights on the river that disrupts the natural flow regime could eliminate this diverse native aquatic community, In addition, this perennially flowing section of river also provides habitat for abundant wildlife including the federally protected bald eagle and larger mammals including elk, deer, black bear and mountain lion, Not only is the aquatic habitat seriously harmed by low flows, so too is the associated riparian vegetation and supporting habitat. Late summer flows vary from near o cfs to approximately 8 cfs downstream of the confluence of Long Hollow, The Bureau of Reclamation (BaR) believes that without enforceable stream flow protection under state water law, along with protection for the riparian corridor, the native aquatic community in the' La Plata River may be lost. The Colorado Division of Wildlife (CDOW) and the u.s, Fish andWildlife Service share this opinion, and , have expressed their support for instream flow protection on this portion of the La Plata River , to the Colorado Water Conservation Board, The CDOW recommends a 15 ds summer flow.