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effective discharge. He further concluded that the channels appeared to be in quasi-equilibrium (dynamic equilibrium). Data from 15 gaging stations supported the correlation between effective discharge and bankfull discharge. Most of the stations were located in coarse bed cobble and gravel streams. For 65 km upstream of the Lily gage, the Little Snake River is a sand-bed river which is subject to potential channel adjustment from upstream water depletions. Vampa River hydraulic and sediment transport data were collected during the period from 1982 to 1983 and the sediment load of the Little Snake River analyzed (Elliott et al. 1984; O'Brien 1984). O'Brien indicated that the most sensitive reach of the Vampa River to changes in the Little Snake River sediment load would be the Deerlodge Park reach. It was emphasized that channel response to reduced flows would be dependent on the revised shape of the seasonal hydrograph and the altered relationship between water and sediment discharge. O'Brien (1984) used a mathematical model to simulate the potential effects of streamflow reduction on cobble substrate reaches in the lower Yampa Canyon. Based on the simulation and aggradation/degradation analysis for the Vampa River for 1983, a high water and sediment load year, there was approximately 288,000 af of water available that year that could be depleted without significantly impacting the relatively sand-free cobble substrate conditions in Yampa Canyon (O'Brien 1984). This analysis used the combined historical streamflow records at the upstream Little Snake River and Vampa River gages. There was no analysis of the potential impacts of flow reduction in either the Little Snake and Vampa rivers. Elliott et al. (1984) collected suspended sediment, bedload and stream discharge measurements of the Vampa River at Deerlodge Park and reported that the river appeared to be in equilibrium in this reach. Mean daily discharge 32