Consent Agenda 3

• Board Meeting Date: 1/22/2008
• Description: WPFM Section - Consent Agenda - Designation and Approval of 100-Year Floodplain Information
• Board Meetings - Doc Type: Memo

Attachment - Supporting Information
Consent Agenda Items 3a and 3b -Designation andApproval of 100-Year Floodplain
Information
SUMMARY
Consent Agenda Items 2.a and 2.b include tvvo Floodplain studies/maps proposed for CWCB action.
Staff is requesting Board designation and approval for these items. A brief summary of the studies is
presented below.
CWCB staff peiTorms technical reviews of floodplain information to assure the Board that the
information is in compliance with the requirements of the CWCB's ``Rules and Regulations for
Regulatory Floodplains in Colorado," 2 CCR 408-1. Furthermore, Sections 31-23-301 and 30-28-111,
Colorado Revised Statutes, state that legislative bodies of local jurisdictions may provide zoning
regulations for land uses on or along any storm or floodwater runoff channel or basin only after
designation and approval by the CWCB. In addition, Section 37-60-106(1)(c), Colorado Revised
Statutes, directs the CWCB to designate and approve storm or floodwater runoff channels or basins
and to make such designations available to legislative bodies of local jurisdictions.
The CWCB's designation and approvals greatly assist local communities in meeting the statutory
requirements of the State and the regulatory requirements of the National Flood Insurance Program.
Floodplain information is broadly categorized as detailed or approximate using the following
definitions. Detailed floodplain information means floodplain information prepared using topographic
base maps, hydrologic analyses, and hydraulic calculations to arrive at precise water surface profiles
and floodplain delineations suitable for making land use decisions under statutorily authorized zoning
powers. Approximate Floodplain information means Floodplain information prepared using a
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 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.