FLOOD04440

• County: Statewide
• Community: All
• Stream Name: All
• Basin: Statewide
• Title: Colorado Flood Map Modernization Business Case Plan - March 2004
• Date: 3/1/2004
• Prepared For: FEMA
• Prepared By: CWCB
• Floodplain - Doc Type: Floodplain Report/Masterplan

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SEellGNTHREE

Program Plan

Coordination Meetings, the identified needs will be incorporated into the countywide mapping
effort to the extent possible based upon available funding. Site-specific engineering needs that
are identified but which cannot be addressed due to a lack of funding will be documented
according to the Site Specific Needs Assessment procedures outlined in Appendix A.

Once the scope for a countywide mapping effort has been completed, the selected engineering
consultant will, in addition to the standard DFIRM tasks associated with the map update for the
selected county, generate planimetric information and base topography and conduct hydrologic
and hydraulic analysis and mapping as needed based upon the scope of the study and terms of
their contract. In addition, the engineering consultant will update non-revised areas, either using
available topography, a Limited Method analysis, or digitization of effective flood hazards based
upon the scope of the study and terms of their contract. The CWCB recognizes the varying level
of effort to update flood hazards and the varying level of accuracy of each one of them.

CWCB believes that the most succinct description of technical standards for accuracy and
quality of floodplain delineation information is contained in a formal resolution adopted by the
Board of Directors of the Association of State Floodplain Managers (ASFPM) at its annual
conference in St. Louis, Missouri on May 12,2003. The resolution in its entirety is included in
Appendix H of this report. The technical standards included within the resolution are listed
below:

. "The flood elevations and the floodplain delineations on the maps must correlate
reasonably to the best available topographic information for the stream and adjacent
corridor.

. The planimetric features on the floodplain maps (streets and highways, stream
centerlines, bridges and other cirtical hydraulic features, corporate limits, section lines
and corners, survey benchmarks, etc.) must correlate reasonably to the best available
aerial photos or other suitable imagery for the stream and the adjacent corridor.

. The flood hydrology used to develop the floodplain map must still reasonably reflect the
flood hazard and meet pertinent local, regional, state and federal technical standards,"

All Map Modernization projects in Colorado will be expected to meet these technical criteria in
addition to technical criteria in the CWCB's Statewide Criteria Manual and FEMA's Guidelines
and Specifications.

The CWCB has identified 16 study tasks that could potentially be implemented in a countywide
map update. These tasks are listed in Table 3.2 below. More information on these tasks,
including definitions, "desired minimum standards", and cost estimating tools is included in
Appendix D.

Colorado Business Case Plan - March 2004

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