Laserfiche WebLink
<br />t <br /> <br />re <br /> <br />t <br /> <br />} <br /> <br />t <br /> <br />f <br />l <br />t <br />t <br />le <br />l <br /> <br />1 <br />l <br /> <br />L <br /> <br />I <br /> <br />L. <br /> <br />III. Hydrologic Analysi s <br /> <br />The design discharges utili,~ed in the design of the floodplain <br />improverrent projects described herein are presented in Table II. 'I11e <br />source of all of these estimates is a detailed hydrologi c study of the <br />D:ry Creek No. 1 drainage basin described in the "Floodplain <br />Infonnation and Flood Control and Drainage Plan - Dry Creek No.1" <br />(1NRC, 1980). <br /> <br />The use of original FIS discha~ge estimates has became imPossible, due <br />to the nnavailability of original hydraulic analysis data (hand- <br />calculated in the FIS) and th: presentation of only discharge values <br />downstream of State Highway 119 in the FIS report. As mentioned in <br />the FIS, discharge rates delivered downstream of SH119 are <br />substantially lessened by the constricted Colorado and Southern <br />Railroad crossing; therefore no FIS estimates are available for the <br />sl~ctions upstream. <br /> <br />In. 1980, the City of IDngmont retained the services of \Iffi.C, Inc. to <br />provide a detailed hydrologic and hydraulic analysis of the Dry Creek <br />No. 1 basin. The use of this :repart for peak flow estimation has been <br />approved by FEMA at the regional level in Denver, the Colorado Water <br />Conservation Board (cvrn), and the City of longment. A coPy of this <br />report is included as suppleJrentary i nformat i on for this amendment <br />submittal. <br /> <br />Table II. Peak Flow Estiwates - Dry Creek No. 1 <br /> <br />Recurrence Interval <br />(years) <br /> <br />10 <br />50 <br />100 <br />500 <br /> <br />Peak. Flow <br />(cfs) <br /> <br />710 <br />1719 <br />2315 <br />4172 <br />