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<br />recorded on July 15, 1989. The Colorado Water Conservation Board estimated the 100-year <br />peak flow to be 1,643 c.f.s. and the 500-year peak flow to be 2,745 c.f~s. This gives some" <br />indication of the rarity of the event. Rainfall and flood conditions continued in the area through <br />early August 1997. The flooding in Otero County occurred as a result of a number of smaller <br />storms over a period of a week. The heaviest rainfall was concentrated in the early part of <br />August 1997. <br /> <br />RECENT FLOOD CONTROL PROTECTION <br /> <br />Congressionally Authorized Corps of Engineers Projects <br /> <br />John Martin Dam and Reservoir, completed in 1948, was the fIrst improvement built by the <br />Corps of Engineers on the Arkansas River in Colorado. The dam spans the Arkansas River about <br />18 miles downstream of Las Animas and 58 miles upstream of the Kansas state line. It is a <br />concrete gravity overflow structure flanked by earth embankments. The reservoir extends 14 <br />miles up the valley and covers about 17,875 acres at maximum pool level. Th.e reservoir storage <br />capacity at the maximum flood pool elevation of 3,870 feet is 605,115 acre-feet. This is based <br />on the November 1994 storage-elevation curve, which was updated to account for estimated <br />sediment depletion. Of this capacity, 277,218 acre-feet is utilized for storage of irrigation water. <br />The water stored in the reservoir for irrigation purposes is released in accordance with the terms <br />of the Arkansas River Compact and at the request of the Compact Administration. In accordance <br />wilh the 1965 Flood Control Act, the Corps of Engineers is authorized to use, but not exceed, <br />10,000 acre-feet of the flood control storage space in John Martin Reservoir for a permanent pool <br />to enhance fIsh and wildlife resources and provide greater recreational opportunities. The State <br />of Colorado is responsible for purchasing the water rights to establish .and maintain the pool. <br />The permanent recreation pool has a minor effect on the flood control capability of the dam. The <br />maximum operating pool elevation allowed including the permanent recreation pool is 3,851.87 <br />feet; corresponding to a reservoir storage volume of 345,698 acre-feet. Currently under <br />agreement with the Arkansas Compact Administration between the State of Colorado and <br />Kansas, the Corps of Engineers is only authorized storage of just under 9,000 acre-feet for <br />permanent recreational use. This equates to an elevation of3,85 1.78 feet and corresponds to a <br />reservoir storage volume of 344,654. <br /> <br />Other improvements constructed by the Corps of Engineers in the Arkansas River basin above <br />John Martin Dam include the Templeton Gap Floodway at Colorado Springs, the Pueblo <br />Floodway Levee Extension at Pueblo, the Fountain Creek Levees and Channelization project <br />also at Pueblo, and the Pinon Canyon Dam at Trinidad. All are single purpose flood control <br />projects. The Templeton Gap Floodway was completed in 1948. It protects an urban area in the <br />northeast section of Colorado Springs from runoff that originates in a bowl-shaped drainage area <br />of about eight square miles and flows down the main channel of Templeton Gap. The floodway <br />intercepts and diverts the flow via a stabilized channel to Monument Creek, a tributary to <br />Fountain Creek. The Templeton Gap Floodway includes 8,713 feet oflined channel with a <br />capacity of 14,000 c.f.s. providing protection up to the 100-year flood. <br /> <br />Post Flood Assessment Report <br /> <br />Chapter 2 - History oj Flooding and Flood Protection <br />9 Draft Revised 09109/99 <br />