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<br /> <br />' predicted mean annual discharge (March or April prediction) with accompanying <br />temperatures of 11C or higher during the May and June migration period is <br /> <br />1 <br />1 <br /> <br /> <br />1 <br />~~ <br /> <br /> <br />1 <br /> <br /> <br />u <br /> <br /> <br />recommended. High spring runoff in Yampa and Little Snake rivers is necessary <br />for adequate sediment transport and maintenance of channel geomorphology in <br />downstream areas. Historic peak flows (including instantaneous peak flows) <br />should not be reduced. <br />Summer: Flows and stream temperatures that occurred during approximate <br />spawning conditions (by type of water year) (Table 2, Figure 7, and <br />accompanying text) are recommended. Flows of tributary streams in Yampa <br />Canyon, including surface and subsur`ace water sources, need protection from <br />aep].etions and degradation of .water quality. Reductions in flo*as prior to, <br />during, and following spawning periods, must occur gradually (as defined by an <br />appropriate hydrograph representing conditions in Yampa Canyon, 1981-1987) in <br />order to prevent siltation of spawning substrate, L-o maintain sediment <br />transport equilibria, to aid downstream drift of larvae, and to create <br />productive nursery areas. Decreases in water s~irface elevation should follow <br />historic pat*_erns. <br />Fall: Fluctuations in water surface elevation departing from historic <br />pattern, are not recommended for maintenance of nursery habitats in the lower <br />Yampa and mainstream Green rivers. Habitat for adults would also be obtained <br />by this regimen. <br />Winter: Extreme daily fluctuations in water surface elevation departing from <br />historic conditions can result in ice scouring of shoreline habitats used by <br />overwintering adults and young. Maintenance of historic winter flow regimens <br />is recommended. <br />45 <br />