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<br />t <br /> <br />Ten percent (10%) of the average flow (fig. 4): This is a minimum <br />instantaneous flow recommended to sustain short-term survival habitat <br />for most aquatic life forms. Channel widths, depths, and velocities <br />will all be significantly reduced and the aquatic habitat degraded <br />(fig. 1). The stream substrate or wetted perimeter may be about ~ <br />exposed, except in wide, shallow riffle or shoal areas where exposure <br />could be higher. Most side channels will be severely or totally dewatered. <br />Most gravel bars will be substantially dewatered, and islands will <br />usually no longer function as wildlife nesting, denning, nursery, and <br />refuge habitat. Streambank cover for fish and fur animal denning <br />habitat will be severely diminished. ~1any wetted areas will be so <br />shallow they no longer will serve as cover, and fish will generally <br />be crowded into the deepest pools. Riparim1 vegetation may suffer <br />from lack of water. Large fish may have difficulty migrating up- <br />stream over many riffle areas. Water temperature may become a <br />limiting factor, especially in the lower reaches of the stream in <br />July and August. Invertebrate life will be severely reduced. <br />Fishing will often be very good in the deeper pools and runs since <br />fish will be concentrated. Many fishermen prefer this level of <br />flow! However, fish may be vulnerable to overharvest. Floating <br />is usually difficult even in a canoe or rubber raft (stream with <br />an average flow of more than 100 cfs). Natural beauty and stream <br />esthetics are badly degraded. Most streams carry less than 10% . <br />of the average flow at times, so even this low level of flow will <br />occasionally provide some enhancement over a natural flow regimen. <br /> <br />19 <br />