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<br />feet to about one-fourth mile and, throughout the study <br />reach, averages about 1,500 feet in width. A wide <br />streambed with low banks characterizes the main-stem <br />river that occasionally shifts across the valley. The <br />tributaries within the study area are ephemeral with <br />narrow channels. <br /> <br />Because of the diversified topography in the region, <br />there is a variety of olimates throughout the study <br />area. Temperatures are charac.teristic of a high alti- <br />tude, dry continental climate, ranging from a high of <br />about 1100F to a low of -320F. The average maximum and <br />minimum temperatures at Trinidad are 67.90F and 34.20F, <br />respectively. The average annual precipitation <br />and in the higher altitudes is in excess of 20 inqhes; <br />and at Trinidad Airport, the average annual precipitation <br />is 13.47 inches. <br /> <br />. <br /> <br />. <br /> <br />Vegetation varies throughout the Purgatoire River Water- <br />shed. In areas above the timberline, the steep mountain <br />slopes are void of vegetal cover. In the timber and <br />woodland areas, aspen, scrub oak, pinon, juniper, and <br />sagebrush, with scattered growths of bunch grass, are <br />found. <br /> <br />The flood plains abound with commercial, industrial, and <br />residential developments, and public utilities. Numerous <br />city streets, state highways, and rail lines cross the <br />flood plains. Continuing economic development within <br />the study area is expeoted, and pressures leading to <br />intensified flood plairi use will undoubtedly accompany <br />such development. Development along the tributaries <br />appears to be gaining momentum without consideration for <br />floodways and drainageways. <br /> <br />2.3 Principal Flood Problems <br /> <br />Large magnitude floods :have occurred on the Purgatoire <br />River at least six times in the last 100 years, causing <br />extensive destruction of buildings, transportation <br />facilities, and utilities. The record discharge of <br />45,400 cubic feet per second was recorded on Septem- <br />ber 30, 1904; the flood of May 19, 1955, caused the loss <br />of two lives and an estimated $4 million in property <br />damage. Figures 2 and,3 shows two scenes of the <br />1955 flood. <br /> <br />. <br /> <br />. <br /> <br />The Purgatoire River and the flood plain at the western <br />city limits extend to about 1,000 feet in width. Down- <br />stream, flood problems develop when flood flows are <br />"funneled" between railroad and highway embankments into <br /> <br />4 <br />