About the North Carolina Floodplain Mapping Program

Introduction
Why Undertake this Project
What Project Will Entail
Benefits from this Project
Management of Program
Components of the Project
- Scoping
- Map Production
- Community Review
Project Schedule

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Introduction

The State of North Carolina, through the Federal Emergency Management Agency's (FEMA's) Cooperating Technical Community partnership initiative, has been designated as the first Cooperating Technical State (CTS). As a CTS, the State will assume primary ownership and responsibility of the Flood Insurance Rate Maps (FIRMs) for all North Carolina communities as part of the National Flood Insurance Program (NFIP). This project will include conducting flood hazard analyses and producing updated, digital FIRMs (DFIRMs).

North Carolina faces extreme hazards and consequences from hurricanes and flooding. Since 1989, there have been 14 federally declared disasters in North Carolina. Damage from Hurricane Floyd alone has reached $3.5 billion. Hurricane Floyd destroyed 4,117 uninsured and under-insured homes. The State's vulnerability to hurricanes and flooding make it crucial that communities and property owners have accurate, up-to-date information about the flood risk. The updated DFIRMs produced through this project will help to protect lives and property and will contribute to the general well-being of North Carolina citizens.

Why North Carolina Is Undertaking this Project

Hurricane Floyd revealed flood hazard data and map limitations.
Approximately 75% of North Carolina FIRMs are at least 5 years old.
Approximately 55% of North Carolina FIRMs are at least 10 years old.
FEMA's mapping budget is finite; on average, North Carolina receives only one updated flood study for one county per year.
Many counties and communities have indicated that they do not have the resources to take on the responsibility of maintaining their own FIRMs.

What This Project Will Entail

Acquisition of high-resolution topographic data and development of accurate Digital Elevation Models (DEMs).
Use of the DEMs to perform engineering studies to develop up-to-date, accurate flood hazard data and floodplain mapping.
Use of the updated flood hazard data and floodplain mapping to produce seamless DFIRM coverage statewide.
Production of DFIRMs on a countywide basis where the county and its incorporated municipalities are shown on the same set of maps.
Production of Digital Orthophoto Quadrangles in partnership with the State of North Carolina and the U.S. Geological Survey will be used as the primary base map. In areas where there is a locally produced base map that is more current or accurate than the Digital Orthophoto Quadrangle, the locally developed map may be used as the base.
Conversion of FIRMs to the North American Vertical Datum of 1988 (NAVD 88).
Implementation of a state-of-the-art, dynamic IT infrastructure to analyze, maintain, and archive maps and associated flood hazard data. This system will also distribute the mapping data and associated reports to the public via the Internet.
Development of a real-time flood forecasting and inundation mapping capability.

The total estimated costs for the Floodplain Mapping Program is $65 million. To date, the State of North Carolina has allocated $25 million for Phase I of the project, which will include development of updated topographic and flood hazard data and production of updated FIRMs for the six eastern river basins (White Oak, Neuse, Lumber, Tar-Pamlico, Cape Fear, and Pasquotank) of North Carolina, which covers roughly half of the State. Phase I will also include development of an online Information Management System to store, disseminate, and archive the data to the public. FEMA has contributed an additional $5.25 million toward Phase I, which is an estimated $36 million effort. The State is actively working with other Federal partners to secure additional funding for Phase I. Future plans include studies of five additional basins in 2001 and the remaining six basins in 2002.

Phases for North Carolina Statewide Flood Mapping Program
Note: FYs are state fiscal years which run from July 1 to June 30.

How North Carolina Communities and Citizens Will Benefit
from this Project

The updated flood hazard data will provide current, accurate information for North Carolina communities and property owners to make sound siting and design decisions when rebuilding after flooding disasters, when building new structures and infrastructure, and when retrofitting existing structures.
The use of the updated flood hazard data by communities for floodplain management will dramatically reduce long-term flood losses in the State of North Carolina.
Updated flood hazard data will alert those at risk of flooding of the need to purchase flood insurance.
It will be faster and cheaper to update FIRMs.
Current, updated base maps and the digital format of the FIRMs will allow users to make more precise flood risk determinations.
The digital format of the FIRMs will allow them to be used with Geographic Information Systems (GIS) for analysis and planning.
The digital GIS will allow online access to all maps 24 hours a day.
The DEMs being developed will be useful for many engineering and planning applications, such as site design, stormwater management, transportation planning and design, and spill response.

How the Floodplain Mapping Program Will Be Managed

The North Carolina Office of State Budget, Planning and Management (OSBPM) will oversee and manage the program in close coordination with the North Carolina Division of Emergency Management. The North Carolina Geodetic Survey, a component of OSBPM, will be involved in the acquisition of topographic data and development of DEMs. The North Carolina Center for Geographic Information and Analysis, also a component of OSBPM, will be involved in the development and acquisition of digital base maps, production of DFIRMs, and implementation and operation of the digital GIS.

The Components of the Project

Scoping

The development of updated DFIRMs for the six eastern river basins will begin with a comprehensive "scoping" phase for each basin. Because flooding sources frequently affect many counties and/or municipalities, it is most efficient to conduct the updated analyses and mapping on a basin-wide basis. The scoping will entail:

Researching and inventorying all available elevation, flood hazard, and digital base map data that may be useful in preparing updated DFIRMs.
Assessing existing flood hazard data (for example, flood elevation profiles, floodplain boundaries, floodways, coastal hazard zones) on effective FIRMs for adequacy.
Where the existing flood hazard data are inadequate, determining the most appropriate technical method to develop up-to-date flood hazard data and establishing a priority level.
Conducting outreach activities with counties and communities to determine needs for updated FIRMs.
Identifying data that need to be developed or acquired, such as digital base maps, DEMs, or field surveys of stream channels, hydraulic structures, and coastal transects.
Determining the proposed scales, paneling scheme, and format (countywide or community-based maps) for DFIRM production.
Developing a schedule for completion of updated flood hazard data and DFIRM production.

Map Production

Using the basin plans developed during the scoping phase and the DEMs being developed, updated engineering analyses and floodplain mapping will begin. A private sector architectural, engineering, and/or surveying firm under contract with the State of North Carolina will conduct this work. The State is currently evaluating letters of qualification from such firms and anticipates selecting the most qualified contractor(s) by November 1, 2000, and having them under contract by December 1, 2000. The work will include two major components: (1) conducting hazard analyses and producing updated, DFIRMs for the six eastern basins and (2) designing and implementing the Information Technology (IT) infrastructure for the mapping program, as discussed earlier.

Community Review

The preliminary countywide DFIRMs will be issued to each county and its communities for review and comment. The State will hold a meeting in each county subsequent to the issuance of its preliminary DFIRM to present the maps and allow the county, its communities, and citizens a chance to comment on the maps. After the meeting, a statutory 90-day appeal period will be provided. During this appeal period, the impacted county, communities, and/or citizens have the opportunity to submit scientific or technical data refuting or contesting the results of the preliminary DFIRM. The final DFIRM will be issued only after all appeals are resolved.

Project Schedule

By March 31, 2001, complete IT infrastructure.
By July 2001, acquire all raw elevation data, develop DEMs and updated flood hazard data, and produce DFIRMs for the Lumber, Tar-Pimlico, and White Oak river basins.
By July 2002, acquire all raw elevation data, develop DEMs and updated flood hazard data, and produce DFIRMs for the Cape Fear, Neuse, and Pasquotank river basins.
By August 2002, work will be completed for the six eastern river basins, which were most impacted by Hurricane Floyd, and account for approximately one-half of the State, affecting 48 counties (in whole or in part) and approximately 21,200 linear miles of streams.
By the end of State Fiscal Year 2005, produce DEMs, updated flood data, and DFIRMs for the remaining 11 river basins in the State. The State's mapping program will then enter the "maintenance" phase.