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<br /> <br /> <br />DEPARTMENT OF THE ARMY <br />ALBUQUERQUE DISTRICT. CORPS OF ENGINEERS <br />P. 0, BOX 1580 <br />ALBUQUERQUE. NEW MEXICO 87103 <br /> <br />SWAED-P <br /> <br />RECEIVED <br /> <br />22 May 1973 <br /> <br />MAY 2 4 1973 <br /> <br />Larry F. Lang <br />Water Resource Engineer IV <br />Colorado Water Conservation Board <br />102 Columbine Building, <br />1845 Sherman Street <br />Denver, Colorado 80203 <br /> <br />COLO. W.~ TER <br />CONSERVATION BOARD <br /> <br />Dear Mr. Lang: <br /> <br />Reference is made to your letter dated 5 April 1973, requesting a floodway <br />analysis for Monument Creek located generally between the Kettle Creek <br />confluence and Woodman Road Bridge. <br /> <br />Data and computations for the 100-year flood plain (existing conditions) <br />were refined before attempting a computer analysis of the floodway. Back- <br />water studies started with water surface elevations established in the <br />Monument Creek Flood Plain Information Report at Woodman Road bridge. <br />Inclosures 1 through 5 show the updated flood plain and water surface <br />profiles in more detail than published in the Report. <br /> <br />During the backwater study, computations reverted to minimum energy 6 times <br />(often failing to balance energy heads) indicating highly unstable flow <br />conditions. Results show an average floodway width of 200 feet to maintain <br />the permissible 0.5 to 1.0 foot increase in water surface elevations. <br /> <br />Several features preclude possible use of a floodway for portions--partic- <br />ularly the meanders--along the study reach. <br /> <br />(1) The stream is deeply entrenched with sharp oxbows. <br /> <br />(2) Meanders impinge on banks and flow would "super elevate" at these <br />points. <br /> <br />(3) As previously mentioned, the flow is in an unstable range. High <br />velocities and "standing waves" are typical for this range. <br />