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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />Velocity of flow during a l00-year flood on <br />the Dolores and West Dolores Rivers would <br />average about 7-8 feet. per second in the <br />channel and 4 feet per second in overbank <br />areas. Above the County Road 30 crossing, Lost <br />Canyon Creek flows in a shallow channel <br />through a gently sloping meadow. In this reach, <br />velocity of floodflow in the channel is moderate <br />and overbank flow velocity is low. Below the <br />crossing, the gradient steepens and velocities of <br />flow are similar to those of the Dolores River. <br /> <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />Water flowing at 10 feet per second will <br />cause severe erosion of channels, destroy low <br />water crossings, and transport large boulders. <br />Streambanks and. the fill around bridge abut- <br />ments may be eroded, and large volumes of <br />sediment transported by water flowing at a rate <br />of 5-7 feet per second. Water flowing at about 2 <br />feet per second or less will deposit sand, silt, <br />and flood borne debris. <br /> <br /> <br />5 <br />