Georgia Takes FEMA Flood Mapping Project by Storm

When officials at the Federal Emergency Management Agency (FEMA) envisioned the Map Modernization Program, put in place in 1999, they knew it would require strong support from state and local agencies to effectively upgrade the entire inventory of more than 100,000 flood panel maps. Because of the critical significance of these maps, FEMA hoped states would contribute resources and expertise to aid in this process.

The State of Georgia took on an ambitious role to do just that. As a Cooperating Technical Partner with FEMA, Georgia is managing a six-year, $18.2 million Flood Map Modernization Program designed to create and update flood insurance rate maps (FIRMs) for all 159 counties and 531 communities in the state by 2009. Nearly 7,000 digital FIRMs, or DFIRMs, are expected to result from this process.

According to Nolton Johnson, P.E., chief of Georgia’s Water Resources Branch of the Environmental Protection Division, “We see this as a tremendous opportunity for Georgia to create a climate of understanding and ownership for the mapping process. Georgia’s map modernization program is unique in that it provides in-kind personnel services that fill voids in federal funding for mapping needs and in the large number of local governments involved.”

In fact, Georgia’s maps utilize a wealth of local data to create significantly improved flood zone delineations. Despite very tight budgets, Georgia has been able to incorporate some new flood studies in almost every county. Now well into the third year of production, this project is a magnet for unprecedented collaborative data gathering between state, regional, and community groups.

Testing the Waters
The Flood Map Project began in 2003 when the Georgia Department of Natural Resources (DNR) selected PBS&J, a leading engineering and consulting firm, to lead the digital data gathering and conversion effort. The map modernization team began the project with the conversion of about 200 FIRMs along with the related data updates to digital format for three counties: Henry, Gwinnett, and Union. Although selected at random, these counties are representative of Georgia in terms of population growth, flooding issues, and other related planning scenarios.

At the beginning of the map modernization effort, the Georgia DNR and PBS&J map modernization project team established a scoping process with the local county officials to refine planning-level cost estimates based on detailed assessment of flood map update needs. These meetings include floodplain administrators, public works directors, zoning and planning staff, and building permit staff from the community. Other state agencies, such as the Georgia Department of Transportation, are also often represented, as their interests and projects often impact the floodplain. Federal agencies with flood control or flood modeling roles such as the US Geological Survey, US Army Corps of Engineers, Natural Resources Conservation Service, and Tennessee Valley Authority provide representation as well. Any agency with a vested interest in improving the quality of flood maps within a county is invited.

Collis O. Brown, CFM, National Flood Insurance Program coordinator for the State of Georgia, explains, “These communities are in the best position to supply this type of information primarily because they are at the ground level–they understand their flood control infrastructure better than anyone else and can ground-truth what the DNR is putting together.”

Detailed Maps
These converted digital maps go well beyond the traditional paper maps that simply depict the state’s floodplains. Built in a geographic information system (GIS) framework per FEMA standards, Georgia’s digital FIRMs reflect a distinctly state and local emphasis, drawing information from local detailed flood analysis models, topographic maps, and aerial photography as well as state information of the same types. The DNR technology framework includes ArcGIS 9.0 mapping and spatial analysis software from ESRI, customized Visual Basic programming, and a number of industry-standard flood hazard data study tools like HEC-RAS and HEC-HMS.

Data acquisition and hydrology and hydraulics (where applicable) are a part of the process and encompass the acquisition or manipulation of data into a format useful for the Flood Insurance Study. In addition, the project mapping specialists register the data to the Georgia state plane coordinates, rectify aerial photos, and, where possible, incorporate hydrologic and hydraulic studies completed by others.

Georgia has recently pioneered two new technical standards for the map modernization project: one for “Limited Detail” study and one for future conditions mapping. Limited Detail study is a hybrid of traditional FEMA approximate study and detailed study. It combines the usefulness of locally available digital topography with supplemental field measurement of hydraulic structures. Georgia has developed and implemented a statewide standard for the creation of these data and their display on the DFIRMs. Likewise, the state has developed a standard for the display of future conditions floodplains on the DFIRMs. Within the Atlanta Regional Commission planning area, computation of future conditions floodplains is mandated by local ordinance, and these data can be displayed on DFIRMs by FEMA specifications. Georgia developed and coordinated a simple method to display the data, resulting in a low-cost but highly useful addition to the DFIRM.

Following this, the state produces the actual GIS DFIRMs using the data gathered or transferred from effective maps. This is a detail-oriented process that involves matching the floodplains to available orthophotography and base mapping and also prepares the cartographic labeling and layouts for the final maps.

Community Review
Once the preliminary map is complete, it is issued to the community for review and formal comment. A meeting is held with the community approximately 30 days after map issuance to discuss the new product. A 90-day appeals period is held if new flood elevations have been posted on the map, and then a six-month compliance period begins during which the community must adopt new floodplain ordinances to match the revised map. Once the community has adopted the new ordinances, the new map becomes effective and is ready for insurance and floodplain management purposes.

Brown adds, “This is such a shift in traditional mapping roles. We’re working side-by-side with the local community. We host public meetings and even conferences that cover everything from the details necessary to customize a map for that particular area to the demonstration of future conditions floodplains, which lines with regulatory requirements.”

From a Trickle to a Flood
Full-scale DFIRM production is currently underway for Cherokee, Cobb, Coweta, Floyd, Gwinnett, Hall, Henry, Paulding, and Union counties in Georgia. The DNR team has already issued preliminary maps in Henry and Coweta counties for review. In Union County, preliminary maps have been issued, and the team is incorporating additional technical data into a revised version of those maps. All six remaining counties will have preliminary DFIRMs issued to the communities by September 2005.

The Georgia DNR Map Modernization team maintains a publicly available Web site (www.georgiadfirm.com) that tracks map modernization progress by county; provides a wealth of downloadable documents, program contact information, and additional links; and allows for the electronic submittal of mapping data quickly and easily. The state is utilizing the Web site to distribute PDF versions of preliminary maps for public review and comment. Additionally, the site contains groundbreaking outreach material designed for a range of audiences. Finally, the state is using a team collaboration site to facilitate communication among the state, its contractor, and FEMA.

As part of the fiscal year 2005 effort, the Georgia DNR is managing map updates for 19 more counties, including Bartow, Bibb, Carroll, Chatham, Clarke, Clayton, Columbia, DeKalb, Douglas, Fayette, Forsyth, Glynn, Houston, Lowndes, Muscogee, Newton, Richmond, Walker, and Whitfield counties.

Award-Winning Collaboration
Georgia recently won a special “Best Practices” grant from FEMA to implement a regionally based flood map scoping system based on the boundaries of the Regional Development Centers (RDCs) within the state. FEMA clearly recognized the state’s special success in the area of outreach and, by providing this special grant, is nationally spotlighting Georgia’s groundbreaking efforts and its position as the state with the most counties in the United States. Georgia’s successful grant application highlighted a plan to consolidate the scoping process at the regional level, reducing travel costs and staff requirements, while at the same time drawing on the well-established benefits of the RDCs for outreach, community coordination, and GIS support. The state plans to publish “lessons learned” as it implements this one-of-a-kind process and pioneers the methodology for other states.

Georgia’s five-year Flood Map Modernization Program is expected to be complete in fiscal year 2009, depending on funding. Currently FEMA is providing the majority of the funding for the project with the State of Georgia and local counties providing substantial amounts of in-kind services, primarily in the form of digital topographic data and community flood studies. Although budgets are extremely tight, the resulting maps issued to the public continue to reflect the highest quality. Georgia is presently projecting a nearly one-to-one in-kind services and data cost share match with FEMA funding over the life of the program. This is primarily because of the availability of statewide orthophotography and a relatively high number of counties with recent topographic data.

Georgia’s program epitomizes collaboration and thrift, focusing on bringing together a wide range of partners, communicating effectively among partners, and getting useful data onto the DFIRMs cost-effectively. With a very limited budget, the state is aggressively promoting the program and the collaborative efforts while producing quality GIS DFIRMs in some of the fastest growing counties in the United States.