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<br />Using the discharges fro~ Table Ir flood e],evations <br />were computed with the Corps of Engineers' steo--backwater <br />program HEC-2. Basic cross section input was ~rom surveyed <br />cross section data furnished by the Colorado Water <br />Conservation Board. The deDth of water in the channel and <br />adj acent flooded areas can be determined from ':he water <br />surface elevations. <br /> <br />Plates 2a and 2b show the areas that would be inundated <br />by the 100-year flood under present conditions. The IO-year <br />flood would be containea with~n the st~eam Chan!l~l, ana the <br />50-year flood would closely follow the patte~n ()! the <br />I DO-year fooe. <br /> <br />Velocity of flow du=ing a 100-yea= ~lood orl the Dolores <br />River would average about 7-8 ~eet per second i!l the channe: <br />and 4 feet per secon~ in overba~k a=eas. Ka~e~ ~lowing a~ <br />abou~ 2 feet ?~r secon~ C~ less Ki:: de?8S~~ 5a:15, 5i:~, an~ <br /> <br />flood borne debris. <br /> <br />Streambanks and the fill a]~oun6 bridge <br /> <br />abutments may be eroded and lc~rge vol wnes of 512(: iment <br />transported by water flo~ing at a rate of 5-7 f~?et Der <br />second. Water flowing at 10 feet pe~ second wi:Ll cause <br />severe erosion of channels, destroy low water =J~ossingsr and <br />transport large boulders. <br /> <br />Substantial Gamage can b~~ expected in the ':OWi'n 0: <br />Dolores given the calculated velocities. In ad(~itio~, any <br />structural ~lood protection measu~es would nee5 to include <br />