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... significantly reduced level of detail to arrive at floodplain (hazard delineation) without water surface profiles. CWCB staff performs technical reviews on the following types of reports and maps for approval and designation by the Board: . . "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 staffwill 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 "rules 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 Al!enda Item 2.a . Floodplain resolution number: FPR 04-574 Affected communities: Jefferson County and Town of Arvada (Urban Drainage & Flood Control District). There is a previously approved hydrology report by the CWCB. Name of study to be formally acted on: "Flood Hazard Area Delineation, Ralston Creek - Leyden Creek" dated June 2004. Studied streams: Ralston Creek and Leyden Creek Technical Issues: This report was authorized by the Urban Drainage and Flood Control District (UD&FCD) and the Town of Arvada. The updated floodplain delineations contained in this report are based on recent topographic information and updated hydrologic analyses for future basin conditions. Ralston Creek was studied from the ArvadaIBlunn reservoir to the confluence with Clear Creek whereas Leyden Creek was studied from Leyden Lake to the confluence with Ralston Creek. The hydrologic analysis was completed using the Colorado Urban Hydrograph Procedure (CUHP), and hydraulic analyses were carried out using the HEC-RAS computer program. Water surface profiles were computed for the 10-, 50-, 100-, and 500-year flood events with 0.5 foot and 1.0 foot floodways. The report was prepared by Boyle Engineering Corporation under contract to the UD&FCD. Community response: The UD&FCD transmitted a letter to the CWCB dated August 25, 2004 requesting CWCB designation and approval of the subject report. The UD&FCD also sent follow-up emails to staff regarding the proposed designation action. The UD&FCD staff worked directly with all of the affected communities during the course of the study and received input and endorsement for the study methods and results. CWCB staff concurs with the UDFCD request for designation and approval of the stud~ ~ Flood Protection. Water Project Planning and Financing. Stream and Lake Protection Water Supply Protection. Conservation Planning 2