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<br />Communitv Response to the CWCB Desil!nation and Approval Process <br /> <br />The community was contacted initially by letter. In a follow up phone call a meeting was <br />arranged with local officials to present the CWCB's proposal to designate and approve <br />approximate floodplain information for Rocky Ford. A meeting was conducted by CWCB staff <br />on April 10, 1996. Local officials in attendance included the town manager and building officiaL <br />Both officials were very receptive to the CWCB's designation and approval of the county's <br />floodplain information. <br /> <br />ENGINEERING METHODS <br /> <br />Hvdrologic Analvsis <br /> <br />Hydrology information for the stream with an approximate floodplain delineation on Rocky <br />Ford's FIRM should be estimated in accordance with the CWCB's "Guidelines for Determining <br />100-Year Flood Flows for Approximate Floodplains" (Guidelines). However, the 100-year flow <br />for the streams with approximate floodplains cannot be estimated by utilizing the regression <br />equation for Arkansas River Basin, Subregion Ark-l because the drainage basin size for the local <br />drainage ponding areas is less than 25 square miles which is less than the lower limit for the <br />Arkansas River Basin, Subregion Ark-I. Additionally, the CWCB has not developed a procedure <br />for determining hydrologic information for local drainage ponding areas. Therefore, a detailed <br />hydrologic and hydraulic study is required prior to any floodplain development. A procedure for <br />determining hydrology information for approximate floodplains of lakes, ponds, and local <br />drainages has not been established. The hydrologic methodology developed in the Guidelines is <br />appropriate for designation and approval of approximate floodplain information and for use in <br />simple floodplain analyses for development such as open space, agriculture, farm bridges, pole <br />barns, and individual single residential structures. The methodology is not appropriate for <br />development involving residential subdivisions greater than 50 lots or occurring on sites greater <br />than 5 acres, commercial construction, industrial construction, construction of public <br />transportation facilities, or construction of flood control facilities. <br /> <br />The Town of Rocky Ford should regulate the approximate floodplains on a case-by-case basis <br />subject to a detailed hydrologic and hydraulic analysis performed by a professional engineer, in <br />accordance with the determinations of the Colorado Water Conservation Board regarding the <br />applicability of the Guidelines. <br /> <br />Hvdraulic Analvsis <br /> <br />The hydraulic analysis for the preparation of the FIRM likely consisted of interpretation of <br />USGS quadrangle mapping by HUD's engineering consultant, along with telephone discussions <br />with local officials. The telephone discussions addressed any historic flood problems that may <br />