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The Coordinated Needs Management Strategy (CNMS) defines an approach for the identification and management of flood hazard mapping needs and requirements that will provide support to data-driven planning and the flood hazard information production planning process. Floodplains inherently change over time, which is a characteristic that makes their management and mapping a challenge. The underlying concern is that there will be an unending supply of mapping needs due to the changing nature of the physical environment, climate patterns, and engineering methods. The CNMS Database is available to communities for review and comments. Please contact the Floodplain Management Program to request the CNMS database.
Components
- Steam study inventory
- Validation process documentation
- Documents local and state needs and requests. for studies to be updated
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What CNMS does
- Tracks needs, requests and study status in a GIS format
- Tool used to report, project and predict New, Valid or Updated Engineering (NVUE) statistics
- Tool to assist with Risk MAP Discovery
- Import component to multi-year and specific project planning
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Benefits of CNMS 
The CNMS is intended to improve efficiencies in communication, documentation, analysis, planning, tracking, and reporting of floodplain mapping needs. Using Geographic Information Systems (GIS) technology to allow for spatial analysis as an effective means to visualize, enter, review, and update a needs inventory. By standardizing and storing data in a geospatial format, CNMS will accomplish the objectives of maintaining current data in a readily available format for improved analysis and reporting.
Validation of Flood studies
The review and analysis of flood studies consists of critical and secondary elements (see table below). There are seven critical elements reviewed to assist in the validation of each flood study. If any one of these critical elements is evaluated to be “Yes” as a result of the identification of a deficiency, it is significant enough to trigger an “Unmet Need” validation status. There are ten secondary elements reviewed to assist in the validation of each flood study. If four or more secondary elements are evaluated to be “Yes” as a result of the identification of a deficiency, that is sufficient to trigger an “Unmet Need” validation status. Please see the inset table detailing the critical and secondary elements considered in this review. The “Unmet Need” validation status signifies that a flood study may no longer provide an accurate representation of the flood risk and suggesting the need for an updated study.
CNMS ELEMENTS
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| Critical |
Secondary |
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Major change in gage record since initial FIRM
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Use of rural regression equations in urban areas |
| Updated and effective peak discharge differ |
Repetitive losses outside of SFHA |
| Model methodology no longer appropriate |
Addition/removal of <=5 hydraulic structures |
| Addition/Removal of major flood control structures |
Increase in impervious area in sub-basin more than 90% |
| Current channel outside of effective SFHA |
Channel improvements/shoreline changes |
| Addition/removal of >5 hydraulic structures |
Availability of better topography data |
| Significant channel fill or scour |
Changes to vegetation or land use |
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Failure to identify primary dune in coastal areas |
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Significant storms with high water marks |
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New regression equations |
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