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<br />. <br /> <br />: ::".,:(:-) <br /> <br />. ~:..:.. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />Beaver dams in this section of stream are breached. <br />Beaver ponds shown in the 1977 aerial photos are no longer present, so the dams may <br />have been breached in the last 23 years. <br />The active channel is not in the lowest part of the valley (see cross-section IT). <br />Bankfull surfaces are poorly defined or absent. <br />Flow in the channel was very low, and the channel could potentially run dry. <br />Slope is variable along the longitudinal profile and there are some steeper ~ections <br />with small waterfalls. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />The critical observation is that the channel does not flow in the lowest part of the valley <br />cross section. It is likely that the channel will abruptly shift its position to the low point <br />during a future high-flow event, possibly next year. One might anticipate that the shift in <br />channel position would not be complete and the channel could split into two separate <br />channels, with some flow in each channel. The summer discharge is quite low (as <br />measured in this project) and splitting the flow could result in extremely low flow and the <br />real possibility that the channel might become dry. This would obviously threaten the <br />population of Colorado River cutthroat trout. <br /> <br />Recommendations <br /> <br />We recommend that this system be monitored for changes in channel position and <br />resulting changes in channel hydrology (width, depth, discharge, etc.). It is possible that <br />the cutthroat trout may have used the beaver ponds as a refuge during low-flow periods. <br />We further recommend that beaver be reintroduced and that the beaver dams be restored <br />in this section of West Antelope Creek to provide this refuge for cutthroat trout. <br /> <br />6 <br />