Laserfiche WebLink
<br />\ <br />I <br /> <br />Previous Studies and Proiects <br /> <br />Several reports have been published regarding the Arkansas River and its tributaries within Fremont <br />County. These reports are listed in the bibliography, Section 9.0, of the PIS. <br /> <br />Community Response to the CWCB Desimation and ADDroval Process <br /> <br />A letter from the CWCB was transmitted to Fremont County regarding the Board's proposed action <br />for designation and approval of the Fremont County PIS. The County was receptive to the Board's <br />proposed actions, and sent an official letter requesting that the CWCB designate and approve the <br />floodplain information currently available to the community. A copy of the request letter is <br />included in the Appendix of this report. A meeting was held between County officials and CWCB <br />staff to discuss hydrology issues, floodplain regulations, and the designation and approval of the <br />PIS. <br /> <br />ENGINEERING METHODS <br /> <br />Hvdrolol!ic Analvsis <br /> <br />Hydrology information used for streams with detailed floodplain delineations in Fremont County's <br />PIS is discussed in Section 3. I of the PIS. Hydrology information for the streams with approximate <br />floodplain delineations in Fremont County's PIS has been estimated in accordance with the <br />CWCB's Guidelines for Determining lOO-Year Flood Flows for Approximate Floodplains <br />(Guidelines). <br /> <br />The lOO-year flow for streams in Fremont County with approximate floodplains (except for the <br />Arkansas River) can be estimated by utilizing one of two regression equations for the Arkansas <br />River Basin. Fremont County faIls within the boundaries of two separate subregions, subregion <br />Ark-3 and subregion Ark-6. Subregion Ark-6 covers the western portion of the county that is <br />generally above an elevation of about 7,500 feet. Subregion Ark-3 covers the eastern portion of the <br />county (including ParkdaIe, Canon City, and Rorence) that is generally below 7,500 feet. Figure 1, <br />presented in the Appendix of this report, displays the subregional boundaries for Fremont County. <br />The regression equations are as follows: <br /> <br />Subregion Ark-3: Ql00 = l089.3(A)o.653 (For kA<930) <br />Subregion Ark-6: Q100 = 45.98(A)o.717 (For 4<A<330) <br /> <br />The Ql00 is the l00-year peak flow in cubic feet per second, and A is the upstream (contributing) <br />drainage area in square miles. The regression curves for subregions Ark-3 and Ark-6 are also <br />presented in the Appendix. The regression equation for subregion Ark-3 is only valid for streams <br />with drainage areas between 1 and 930 square miles, and the regression equation for subregion Ark- <br /> <br />3 <br />