Background

Changes in the ways FEMA interprets the definition of "floodway" at the federal level have made developing certain flood prone areas extremely difficult in the Metro Atlanta region. At the local level, development in floodplains is generally accepted provided certain standards are met, which vary by municipality, but development in the floodway, which is a narrow band central to a stream or river where dangerously high velocities and heavy erosion are encountered, are explicitly prohibited. At the federal level, very little attention is paid to development in the floodplain, other than ensuring that the maps stay accurate, while development is restricted by review in the floodway.

As maps have undergone revision and refinement in the last decade, FEMA policy has dictated that the "floodway" designation, ordinarily reserved to areas of high velocity in the stream or river, be expanded to the edge of the floodplain in areas where FEMA flood modelers have identified significant storages. This may be to ensure that federal agencies have an opportunity to review significant fills in these storage zones, which would impact their model. But the rule makes large zones upstream of road culverts in Metro Atlanta, which might have no dangerous velocities in them at all, undevelopable, because of the "floodway" designation. It is a case where federal rules and local rules don't mix well, yielding tremendous complications for developers and land owners. CCC has recently negotiated two such projects for land owners, to allow them to build safe projects within safe areas of the floodplain, which were designated "floodway" by FEMA and therefore require a variance from adopted development codes.

Case 1:

As a floodplain and floodway expert subconsultant to Breedlove Land Planning, Campbell Civil Consulting performed a floodplain and floodway analysis of a future Atlanta Youth Soccer Association site, in support of one of the few floodway variances granted under the 2008 Dekalb County Ordinance. The project site was a single family residence on a 13.44 acre tract on Glenwood Road in Decatur Georgia, which was mostly undevelopable land, owing to its designation as a floodway on the most recent Federal Emergency Management Agency Flood Insurance Rate Map. (FEMA FIRM) While the open floodplain was not suited to typical in-town redevelopment, it was an ideal site for a soccer field and associated appurtenances, which may still function safely when the area is not subjected to inundation.

CCC followed Dekalb County "no rise certification" procedures for the project, extracting section data from topographic and bathymetric survey, revising the HEC-RAS model for the stream to show no appreciable effect to the floodplain from grading activities related to the construction of the soccer field, and presented the results of the analysis to the Dekalb County Zoning Board of Appeals. The board approved the application, and granted AYSA the right to proceed with their soccer field project.

Case 2:

CCC also worked with Breedlove Land Planning on a similar project at Atlanta Silverbacks Park, a local soccer stadium facility which facilitates a NASL soccer club as well as numerous adult recreational leagues. Also situated within Dekalb County, Atlanta Silverbacks Park was formerly constructed in a floodplain, which was retroactively designated as floodway by FEMA during a flood map revision, applying the same rule described above. The Silverbacks owners were aware of prior instances of flooding on the property, and knew no dangerous velocities were present due to backwater effects of the downstream culvert, so sought to seek a variance for new site improvements on the park property. CCC worked with Dekalb County, the Silverbacks organization, and Dewberry, the county's floodplain modeling consultant, to make adjustments within effective and proposed flood models as they were submitted to FEMA for review, to better characterize the flood conditions on the site. CCC then worked from the adjusted models to again show "no rise" from the proposed site improvements, so the project could proceed. CCC also handled a required stream buffer variance application with the county in tandem with the floodway variance, presented both variances at the zoning board of appeals, and both were approved by Dekalb.

CCC has extensive experience with floodplain and floodway modeling, "no-rise" analysis for flood encroachment, and peer review of existing flood models. We have testified in state court regarding flood map discrepancies, and are an expert in how land development projects interact with regulatory floodplains and floodways.