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-i Self-formed reaches of channel near each stream gage were surveyed and the bankfull discharge computed. At each of the gaging stations, the effective discharge and the bankfull discharge were nearly equal. Andrews' conclusion was that the stream channels appear to be adjusted to their effective discharge. O'Brien (1982) studied the cobble bar, riffle-pool habitat reach between Harding Hole and Warm Springs Lake. His results include: The reach is supply limited; all sediment supplied to the reach is transported through the reach, primarily due to the steep stream gradient. Using incipient motion criteria, the cobble pavement of the Mathers Hole site will not move until 'bankfull' discharge is achieved or exceeded. The return period of the 19,530 cfs 'bankful' discharge was not determined. Bedload and bed material samples were analyzed, and suspended, bedload, and total sediment transport curves were determined. Using the Meyer-Peter and Mueller equation for bedload, and the Einstein method for suspended load, transport curves were estimated by size fraction. A sediment budget analysis was preformed for years 1959 to 1964, including the simulated reservoir discharges from the proposed Juniper/Cross Mountain Project. In the analysis, the sum of the Little Snake near Lily and Yampa River near Maybell daily suspended sediment loads were used as the supply available to the Deerlodge Park - Mathers Hole reach. Bedload was assumed as I either 4% or 10% of the combined suspended loads. For the transport capacity portion of the budget, I cannot tell whether the measured or calculated rating I curves were used. The conclusion was there appeared to be no major impacts [_from sand storage on the spawning substrate at Mathers Hole. A qualitative assessment of the adjustment of the Deerlodge Park reach to the Juniper/Cross Mountain Project was also presented. O'Brien (1984) ., studied three cobble bed sites at RM 16.5, 17.5, and 18.5 on the Yampa River. Effective discharge at Mathers Hole (RM 17.5) was calculated to be 11,500 cfs while the bankfull discharge of 21,500 has a return period of approximately 20 years (Gumbel extreme value distribution). This value represented a refinement of the previous estimate. It was determined that the cobble bed would mobilize at approximately bankfull discharge. The Yampa River at this non-alluvial site is not related to effective discharge, but to large, infrequent events. The hydraulic and substrate conditions at RM 16.5 were modeled in a flume study ,at CSU and included in O'Brien's report (O'Brien, 1984, & Berry, 1985). It was observed that sand particles could only be scoured to a maximum depth of one Laverage cobble diameter without mobilizing the cobble bed. ( 4 %z - l ° ^v!? ) ,