Floodplain Revisions

Updated Flood Maps 2023

It is anticipated that the flood maps would be ready for local adoption in summer of 2023. In general, the updated flood maps portray a slightly smaller floodplain footprint and slightly lower flood depths under the 100 yr. (1% Annual Chance) flood scenario – known as the “Base Flood”. For approximately 95% of impacted properties, the revisions to the flood maps will result in less restrictive floodplain development requirements or no change from the effective maps. 

If your property will have more restrictive development requirements, you will receive a mailer that explains the changes and provides contact information for more questions.

Background

The ten miles of Roanoke River that flow through Roanoke City represents an important asset to the community (flood passage, recreation and environmental quality). As the river is subject to periodic flooding, the City has implemented various projects to reduce flood related impacts – the largest of these was the Roanoke River Flood Reduction Project (RRFRP). This project entailed extensive acquisition of flood prone properties and the construction of levees, flood walls and flood storage “bench cuts” along the River to protect critical assets and reduce flooding. The project was a partnership between the US Army Corps of Engineers (USACE) and the City of Roanoke, with the total cost of the project estimated at $70M+ (construction between 1990 and 2012).

The RRFRP significantly changed the River landscape, including the removal of approximately 0.4 million cubic yards of stream bank along six miles of the River. This landscape change modified the hydraulics of the river – flood depth and extent – and as such it was necessary to revise the FEMA floodplain boundaries to reflect the changes made by the RRFRP. To do this, staff engaged ESP Associates, Inc., a technical expert in floodplain modeling and mapping, to revise the floodplain maps and shepherd the revisions through the FEMA map change process, known as a “Letter of Map Revision” (LOMR). The proposed maps were initially submitted to FEMA in May 2021 and have undergone several iterations of technical and administrative review. At this stage of the LOMR process, the property owners along the River that will be affected by flood map changes are in the process of being notified. 

What is a Flood Map?

Everyone lives in an area with some flood risk—it’s just a question of whether you live in a high-risk, low-risk, or moderate-risk flood area. Flood maps show a community’s risk of flooding. Specifically, flood maps show a community’s flood zone, floodplain boundaries, and base flood elevation.  Learn more here.