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2.6 At the mouth of the Cornet Creek canyon, near the apex of the all uvi a 1 fan, a berm was constructed to di rect flows into the exi st'l ng Cornet Creek channel across the fan. Figure 2.4 is a photograph of this berm. Historical accounts and discussions with public works personnel for the town indicate that the berm was not structurally engineered. The berm was formed by the accumulation of materials periodically cleared from the channel at the mouth of the canyon. Historical accounts indicate that the berm was originally established during the years prior to 1914. It was apparently constructed in an effort to divert the creek from a hi stori c southeast course through the ma i n part of town to a southwest location, in what was then the outskirts of the town. The stability of the berm during a significant flow event is questionable. During a 1914 mud flow event, the berm was swept away resuHing in severe damages on the eastern side of the fan. Failure of the existing berm could result in abandonment of the existing Cornet Creek channel and extend the area of flood inundation. Through town, the channel is crossl,d by several roadway and pedestri an bridges. Figure 2.5 details the location of hydraul"ic structures along the creek. The hydraul ic capacity of many bridges' may be inadequate to pass a significant mud flow event. Obstruction of bridges by debris carried by'mud flows is possible. The Cornet Creek channel through the town is approximately 3 to 8 feet in depth, 10 to 25 feet wide and 1,300 feet 1 (lng from the S,an Mi gue 1 River to the mouth of the canyon. The hydraul i c capaci ty of the channel is 1 i mited. The occurrence of significant sediment deposition within the channel or obstruction of any of the numerous bridges along its course would result in overbank flooding. Figure 2_6 is a photograph of a typical chann"l section and culvert along the creek.