ca2a_ 2e - Laserfiche WebLink

Home Browse Search

. "Flood Insurance Study" (FIS), which is produced by the Federal Emergency Management Agency (FEMA) and used for floodplain management, regulation, and insurance purposes. . "Flood Insurance Rate Map" (FIRM), which is produced by FEMA and used for floodplain management, regulation, and insurance purposes. A FIRM may be published with or without an associated hydrologic and hydraulic report. . "Flood Hazard Boundary Map" (FHBM), which was produced by the Federal Insurance Administration and are used for floodplain management, regulation, and insurance purposes. An FHBM usually depicts approximate floodplain boundaries only, and does not have an accompanying report. Note: For all FHBM designations, the CWCB staff will perform (in-house or by contract with a consultant) hydrologic analyses. . "Floodplain Information Report", which is produced by local governments, state and federal agencies, special districts, or the private sector, and are used for floodplain management purposes and sometimes adopted by FEMA for use in Flood Insurance Rate Map revisions. . Various hydrology studies and related floodplain studies (community-wide or site specific) that depict 100-year floodplain information that is useful for floodplain management purposes. . "Floodplain Information" is a generic term used to describe any of the above types of reports and/or maps in the CWCB' s "mles and regulations..." . "Floodplain Resolution" is a formal document prepared by CWCB staff describing the Floodplain Information that is to be designated and approved by the Board. 1) Consent A2enda Item 2.a Floodplain resolution number: FPR 07-602 Affected communities: Jefferson County, City and County of Denver, City of Wheat Ridge, City of Golden, City of Arvada. Name of study to be formally acted on: "Flood Hazard Area Delineation, Clear Creek, Jefferson County & City and County of Denver" dated April, 2007, by ICON Engineering. Studied streams: Clear Creek Technical Issues: This report was authorized by the Urban Drainage and Flood Control District (UDFCD) under joint sponsorship with the City and County of Denver, the City of Wheat Ridge, the City of Golden, the City of Arvada, and Jefferson County. The purpose of this report is to update flood hazard data for Clear Creek from Sheridan Boulevard to approximately 2,200 feet upstream of Highway 6 above Golden, to produce new floodplain delineations and profiles for the 100-year event, to produce new profile infol1nation for the lO-year event, and to define floodways for the subject stream reaches. Hydrology from previous studies developed by the U.S. Army Corps of Engineers was used in this report. The total study area includes approximately 475 square miles of drainage area extending up to the Continental Divide in Clear Creek County. Hydraulic analyses were carried out using the U.S. Army Corps of Engineers River Analysis System (HEC-RAS) based on steady flow conditions. Several areas of split flow were identified and analyzed. Floodways were computed assuming both 0.5' and 1.0' rise criteria, which are consistent with both FEMA and local jurisdiction regulations. Community response: UDFCD transmitted a letter to the CWCB dated June 25, 2007 requesting CWCB designation and approval of the subject report. A designation request letter dated June 27, 2007 was received from the City of Arvada. Although no other designation request letters were received, conversations with officials from the other affected jurisdictions indicate that they all request designation and approval of the subj ect repOli. Staff findings: CWCB staff has determined that the subject 100-year detailed floodplain information for the studied stream reaches is conformance with the CWCB's mles and regulations for floodplain designation and approval. The CWCB staff has relied on the technical competence of ICON Engineering, Flood Protection. Water Project Planning and Financing. Sn-eam and Lake Protection Water Supply Protection. Conservation Planning 2