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28 002478 Following the large scouring event during the channel-cleaning flows of May 1965, the bed at the Upper Cableway never refilled to pre-dam elevations. The Upper Cableway discharge measurements made between May 1965 and December 1966 show that the elevation of the bed at its maximum fill following the 1965 scouring event was still about 6 m lower than the typical filled-condition bed elevation prior to May 1965. These changes are also recorded in the Reclamation surveys made between 1956 and 1965. Subsequent surveys at this cross-section show that the thalweg at the Upper Cableway has never been higher than 0.3 m above the elevation measured in December 1966. By January 2000, the bed had degraded an additional 2.2 m lower than the lowest elevation measured in 1965. Although the post-dam measurements are infrequent compared to the pre-dam measurements and may miss periods of bed-sediment aggradation, the timing of these measurements suggests that sediment accumulation has not occurred since 1965. Lower Lees Ferry Cableway The time series of minimum bed elevation for the Lower Cableway has frequent and wide gaps between measurements. Most Lower Cableway measurements were made at high discharge, and therefore tend to represent the bed in a scoured condition and do not describe the annual refilling of the channel, which occurred during seasons of lower average discharge (Figure 13). During pre-dam floods, the bed typically scoured to an elevation of about 941 m. The few measurements that were made in months other than the snowmelt flood season indicate that the cross-section filled to about 945 m. The January 2000 measurement shows that there has been far less post-dam degradation at the Lower Cableway than 0.8 km upstream at the Upper Cableway. The 2000 measurement was made at a discharge and time of year when the bed at the Lower Cableway was typically at a maximum and is probably representative of the post-dam filled condition. The bed is at approximately the same elevation as pre-dam years during the annual flood. Post-dam erosion has not degraded the bed to below the elevation of pre-dam maximum scour, as has occurred at the Upper Cableway.