BOARD01263

• Board Meeting Date: 7/18/2005
• Description: Flood Section - Floodplain Designations
• Board Meetings - Doc Type: Memo

STATE OF COLORADO

Colorado Water Conservation Board
Department of Natural Resources
1313 Shennan Street, Room 721
Denver, Colorado 80203
Phone: [phone]
FAX, [phone]
www.cwcb.state.co.us

Bill Owens
Governor

MEMORANDUM

Russell George
Executive Director

TO:

Colorado Water Conservation Board Members

Rod Kuharich
Director

FROM:

Tom Browning, P.E., Flood Protection Section

Rick Brown
Acting Deputy Director

DATE: July 6,2005

SUBJECT: Consent Agenda Items 2.a and 2.b
July 2005 Board Meeting
Flood Protection Section - Floodplain Designations

SUMMARY

Consent Agenda Items 2.a and 2.b include two floodplain studies with maps proposed for CWCB action. Staff
is requesting Board designation and approval for these items. A brief surrunary of the studies is presented below.

CWCB staff performs 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 the designation and approval of
floodplains and of storm or floodwater runoff channels 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.