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<br />" <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />than I foot are expected within the Town for the 100-year event. FEMA indicates that 1% chance <br />flooding areas (100-year floods) with average depths ofless than 1 foot should be designated as shaded <br />Zone X. (flood insurance is not required in this zone). The CWCB's Consultant recommends that the <br />existing Zone A (approximate lOO-year floodplain; flood insurance is required in this zone) designation <br />shown on the Flood Hazard Boundary Map should be removed and rescinded. <br />Community response: A letter from the CWCB was transmitted to the Town of Manassa regarding the <br />CWCB's proposed action for designation and approval of floodplain information for the Town. The <br />Town was receptive to the CWCB's proposed action and sent an official letter requesting that the CWCB <br />designate and approve the floodplain information now available to the community. The community was <br />also contacted via telephone during the study process to obtain data and other general information <br />pertinent to the study. <br />Staff findings: The subject Floodplain Information Report for the Town of Manassa contains the most <br />current floodplain information (approximate lOO-year floodplain delineations) for the Town. CWCB staff <br />has determined that the subject floodplain information report for Manassa is in conformance with the <br />CWCB's rules and regulations for floodplain designation and approval. <br />Staff recommendation: Staff recommends that the Board: I) designate and approve the 100-year <br />floodplain information contained in said report for the Town of Manassa, 2) rescind the approximate <br />Zone A floodplain currently shown on the Flood Insurance Rate Map dated February 19, 1986, and 3) <br />authorize staff to prepare a floodplain resolution to be signed by the Director and transmitted to the Town <br />of Manassa, Conejos County, and FEMA. This action is recommended in order to meet statutory <br />requirements. <br /> <br />4) Consent Al!enda Item 2.e <br />Floodplain Resolution Number: FPR 04-578 <br />Affected Community: City of Orchard City (Delta County) <br />Name of study to be formally acted on: "Floodplain Information Report, City of Orchard City, <br />Colorado" dated September 2004. <br />Studied Streams: Surface Creek, Cedar Run, and Tongue Creek <br />Technical Issues: The update of the hydrologic analyis for Surface Creek, Cedar Run, and Tongue <br />Creek for the FIR uses the most recent update of the USGS regression equation manual. Peak flows for <br />the 10-, 50-, 100-, and 500-year events were computed at various design points for the streams of <br />interest. Rather than using the regional equations published in the USGS manual, peak flows for <br />Surface Creek were computed using the area ratio equation since stream gage flood-frequency <br />estimates were available. Regional regression equations were used to estimate peak flows for Tongue <br />Creek and Cedar Run. The 100-year floodplain delineations in Orchard City for Surface Creek and <br />portions of Cedar Run presented in the FIS and on the FIRM and FBFM were determined using the <br />HEC-2 hydraulic computer model. Floodplains and floodways for Cedar Run and Surface Creek and <br />portions of Cedar run in the city are based on detailed methods. Approximate methods were used for <br />portions of Tongue Creek, portions of Cedar Run, Alfalfa Run near Fruit Growers Reservoir and for a <br />very small portion of Currant Creek. There is no hydrologic or hydraulic data to support the <br />approximate floodplain delineations for Alfalfa Run and Currant Creek. <br />Community response: A letter from the CWCB was transmitted to the City of Orchard City regarding <br />the CWCB's proposed action for designation and approval of floodplain information for the City. The <br />City was receptive to the CWCB's proposed action and sent an official letter requesting that the CWCB <br />designate and approve the floodplain information now available to the community. The community was <br />also contacted via telephone during the study process to obtain data and other general information <br />pertinent to the study. <br /> <br />Flood Protection. Water Project Planning and Financing. Stream and Lake Protection <br />Water Supply Protection. Conservation Planning <br /> <br />5 <br />