Laserfiche WebLink
<br />I <br />L 0615 <br /> <br />- <br /> <br />e <br /> <br />75. In the upper reaChes, the channel is well armored with rock <br /> <br />and boulders which resist the erb$ionbf normal flows. However, the <br />swift currents inherent to flood discharges cause bank caving and often <br />I <br /> <br />undercut the grades of the highwaY and railroad confined to the narrow <br /> <br />canyon. <br /> <br />76. Beginning about ten miles, u~stream from Trinidad, the floor of <br /> <br />the canyon is somewhat wider than the stream bed; terraces adjacent to <br /> <br /> <br />the ~tream in this reach have been develbped into irrigated farms. <br /> <br /> <br />Floods frequently inundate these low-lying lands, and since th<;ly are of <br /> <br />fine-grained alluvial material, they are subject to severe Uank caving <br /> <br />during floods. Irrigation diversion works serving these small tracts <br /> <br />are generally of light construction and are damaged or destroyed even by <br /> <br />minor floods. In addition to the damage to the structures, the crops <br /> <br />served Qy the canals may be seriously damaged Qy lack of water unless <br /> <br />the diversions are rebuilt immediately after the floods. <br /> <br />77. 'Ihe most serious flood pl'oblem area on the Purgatoire River is <br /> <br />in the city of Trinidad. Trinidad has been protected from small floods <br /> <br />during the past 48 years by the locally constructed floodway through the <br /> <br />city, which is described under the section entitled "Existing Improve- <br /> <br />ments." However, the original capacity of the floodway was not adequate <br /> <br />,to contain a major flood without overflow into the city. The channel is <br /> <br />particularly restricted upstream from the Commercial Street bridge <br /> <br />because of the low floodway wall on the outside of the bend in front of <br /> <br />the Atchison, Topeka and Santa Fe Railway station. It is further re- <br /> <br />stricted by the small waterway under the Commercial Street bridge and the <br /> <br />deposition of sediment in the channel above the Baca Diversion Dam. The <br /> <br />floodway walls terminate near the Baca Diversion short of the downstream <br /> <br />limits of the urban area, thus leaving a large urban area unprotected. <br /> <br />The major flood of 1942 seriously damaged the floodway which had deteri- <br /> <br />orated considerably with age in spite of efforts by the city to maintain <br /> <br />30 <br /> <br />. <br /> <br />