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<br />. <br /> <br />. <br /> <br />. <br /> <br />Communitv Response to the CWCB Desilmation and Aoproval Process <br /> <br />The community was contacted initially by letter. In a follow up phone call, the town clerk was <br />provided a description of the designation and approval process. She agreed with the Board's <br />initiative to designate and approve the local drainage area and indicated that the town had no <br />problem with the CWCB doing so. <br /> <br />ENGINEERING METHODS <br /> <br />Hvdrolol!ic Analvsis <br /> <br />Hydrology information for the local storm drainage area with an approximate floodplain <br />delineation on Walsh's FHBM should be estimated in accordance with the CWCB's "Guidelines <br />for Determining 100-Year Flood Flows for Approximate Floodplains" (Guidelines). However, <br />the 100-year flow for Walsh's floodplain cannot be estimated by utilizing the Guidelines because <br />the drainage basin size is less than 0.25 square miles and is considered to be a local storm <br />drainage area. Therefore, a detailed hydrologic and hydraulic study is required prior to any <br />floodplain development. A procedure for determining hydrology information for approximate <br />floodplains of lakes, ponds, and local drainages has not been established. <br /> <br />The Town of Walsh should regulate its approximate floodplain on a case,by-case basis <br />subject to a detailed hydrologic and hydraulic analysis performed by a professional engineer and <br />submitted by a developer or development proponent, in accordance with the determinations of <br />the Colorado Water Conservation Board regarding such activities, <br /> <br />Hvdraulic Analvsis <br /> <br />The hydraulic analysis for the preparation of the FHBM 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 />have occurred in Walsh. The FIA did perform and did not have the benefit of any detailed <br />hydrologic and hydraulic analyses for the preparation of the FHBM. Future detailed hydraulic <br />analyses should be performed using accepted engineering methods. <br />