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, 0616 , . the works in good repair. Since that time deterioration has increased to the point that the city is unable to maintain it in serviceable con- di tion to safe~ pass' flood flows. 78. The high velocities of flood gi?9har~e? exceed ?upercriti9al in some'reaches through the City and create two serious problems. First, the swift currents demolish all light structures in their paths; and second, they cause extensive bank caving. A map published by tl1e U. S. Geological Survey, in ~-Supply ~ Irrigation, Paper 147, shows that during the 1904 flood, bank caving widened the river channel through Trinidad by about 100 to 250 feet. The flood of 1942 caused caving up to 100 feet into the banks, undercutting the floodway wall and a set of railroad tracks in front of the Atchison, Topeka and Santa Fe Railway depot. Also, a head cut undermined the north approach to the Commercial Street bridge, and scoured a by-pass channel to the north of the Baca Diversion Dam. Below the Baca Diversion Dam, bank caving advanced about 100 feet into the south approach of the Colorado and Southern RaiJway bridge. Downstream the current attacked the 10_foot north bank, and advanced through a half-block on the river side of Cottonwood Avenue, to the north side of the street on a front of more than two city blocks. 79. Downstream from Trinidad to the n~uth of San Francisco Creek through an irrigated agricultural area, flood problems result from in- undation, erosion, and scour. Floods in excess of the 15,000 cubic feet per second channel capacity inundate agricultural landa, deposit sedi- ment in backwater areas, and scour lands in the path of high velocity elements of the flow. The irrigation diversion structures were not designed to pass floods equal in magnitude to the maximum flood of re- cord without sustaining damage and many of the diversions are of such light construction that they are severely damaged or destroyed even by minor floods. 31 e