Roanoke on Tuesday announced the approval by the Federal Emergency Management Agency of new floodplain maps for the Roanoke River that reflect decades of flood mitigation work along the banks of the waterway.
The new maps indicate the likelihood and severity of flooding for more than 1,400 parcels along the approximately 10-mile Roanoke River corridor within city limits, according to a news release from the city. Land development and flood insurance requirements are also updated.
The vast majority of the properties surveyed either remained in the same flood designation or moved into a lower-risk category.
Forty-four percent of the properties, or 636, were deemed to be at lower risk than previously, which could facilitate land development and potentially reduce insurance requirements, the city said.
The designations of 751 properties, or 52% of those studied, remain unchanged from previous maps.
The remaining 49 properties, or 4% of the total surveyed, now face more stringent land development requirements or the need to acquire flood insurance.
Owners of properties that are unchanged or have been switched to the lower-risk category can visit the “Flooding in Roanoke” page on the city’s website. The information will also be mailed to all property owners in the floodplain.
The owners of properties that were shifted to the higher-risk category will receive letters detailing the changes in land development requirements and the potential need for flood insurance. They can also attend the city’s “Prepareathon” from 10 a.m. to 2 p.m. Sept. 16 at the Berglund Center, where they can talk to the city’s stormwater staff.
Marcus Aguilar, civil engineer in the stormwater division, said that while the new maps may result in initial concern for some residents, his team hopes that appropriate management of flood risk based on the new maps will actually reduce anxiety about flooding over the long run.
“This study provides the most accurate portrayal of flood risk along the Roanoke River and will allow property owners to insure their assets appropriately against potential flood damages,” Aguilar said in the release. “Additionally, the new map will help guide the placement and configuration of new and re-development along the River to minimize damages from flooding.”
The updated floodplain maps not only reflect significantly improved data and flood mapping methods, but also incorporate the changes made by the Roanoke River Flood Reduction Project, a $72.5 million collaboration dating to the 1980s between Roanoke and the U.S. Army Corps of Engineers.
During the decades that the project was underway, the city acquired flood-prone properties, built levees and floodwalls and created bench cuts along the river.
“The goal is just to let the river flood areas, that if it floods, it doesn’t really matter,” Aguilar said Tuesday. “Maybe it dropped some sediment, we have to clean it up. But otherwise, it’s not that big of a deal.”
The flood reduction project significantly changed the landscape of the Roanoke River, including the removal of about 0.4 million cubic yards of stream bank along 6 miles of the waterway, according to city information about the project.
Those changes meant that FEMA’s floodplain boundaries also needed to be updated. The new maps were submitted to FEMA in May 2021 and went through several rounds of review, the city said.
“The resulting maps are a very accurate representation of the Roanoke River Flood Reduction Project and other important updates since the River was last studied, and the maps will be a valuable resource as our Community works towards long-term flood resilience,” Aguilar said in the news release.
According to the city, FEMA granted approval for the updated flood maps on Aug. 4.
The city’s GIS site will soon include the updated information, but for now property owners should go to the zoomable map on the Floodplain Revisions page. The map shows flood hazard areas including, in dark blue, the floodway, consisting of the river channel and immediately adjacent areas that are regulated to ensure safe passage of floodwaters. It also shows, in light blue, areas with a 1% annual chance of flooding, and in orange, areas with a 0.2% annual chance of flooding.
To see individual parcels, go to the layer list and click on “Roanoke River LOMR Parcel Impacts.”
For more information, property owners may call the Stormwater Utility Department at 540-853-5900 or email firstname.lastname@example.org, to the attention of the floodplain manager. Be sure to provide the property address.