Landslides, sinkholes and flooding focus of latest Hamilton County hazards mitigation plan

A section of hillside beneath a Mapco gas station slid away after heavy rainfall, seen on Wednesday, Feb. 20, 2019, in Wildwood, Ga. Continuous rain through the week has raised area waterways to flood stages, with more rain expected in the coming days.
A section of hillside beneath a Mapco gas station slid away after heavy rainfall, seen on Wednesday, Feb. 20, 2019, in Wildwood, Ga. Continuous rain through the week has raised area waterways to flood stages, with more rain expected in the coming days.

An updated hazards mitigation plan for Hamilton County focuses on flooding, landslides and sinkholes after record rainfall in the Tennessee Valley for more than a year.

The Federal Emergency Management Agency mandated-plan develops a county-wide strategy to reduce the impacts of natural events with input from jurisdictions, government agencies, university researchers and the public.

"Natural hazards are an inevitable fact. Human ingenuity can do nothing to stop a tornado or winter storm from occurring," according to the plan. "Planning for natural hazards and implementing mitigation measures, however, can reduce the impact of such events when they do occur."

Since 2000, there have been 34 documented flood events in Hamilton County, causing an annual average of $1.3 million in property damage. Last year was the wettest year on record for the Tennessee Valley, with more than 67 inches of rain, and one of the wettest years in the history of Chattanooga. The rain highlighted the geological dangers in the Chattanooga area as steep slopes slid into roadways and holes opened in parking lots of local businesses.

The hillside beneath a Mapco station slid away in late February. Later that week, a mudslide crushed a Subway restaurant on Signal Mountain Road, followed by a later landslide in the parking lot of AwardCountry.com off nearby Dayton Boulevard.

Several small sinkholes have caused problems for local businesses in the last year, a 15-foot deep sinkhole opened in a Soddy-Daisy soccer field last year, and the previous year a sinkhole at Mountain Brook Apartments, now Rise at Signal Mountain, engulfed a resident's car.

The county's office of emergency management and homeland security has updated its plan to continue reducing risk in such areas. It has partnered with the University of Tennessee at Chattanooga Department of Geology to look at the history of sinkholes and landslides in the area as well as soil types to see what areas would be susceptible in the future.

From there, they'll work to help ensure development projects consider such factors, and they hope the information can be used to help jurisdictions work to make smart decisions to limit risk.

The office of emergency management and homeland security plans to use the study to try to get grants to continue the UTC research. It also plans to help local communities apply for grants to purchase property from people living in homes that are regularly flooded. Chattanooga has done so already in areas such as Aster Road. The city buys the property from the owners, allowing them to move, and then tears down the homes to create an open flood plain.

"This is one of the hardest plans that we work on because it's multiple jurisdictions, and you have to get everybody to update their projects and look at their long-range [efforts], what they're going to try to do to mitigate certain things," project lead planner Gregory Helms said.

The county began implementing the FEMA-mandated mitigation plans shortly after the turn of the 21st century. By 2004, all municipalities without an approved plan would be ineligible for certain types of disaster assistance. The plans are required to be updated every five years.

It has been sent to the state for review and then will go to FEMA for final approval or to find out if anything needs to be fixed.

The hazard mitigation plan is always open for public comment. Comments may be sent to gregoryh@hamiltontn.gov.

Contact staff writer Mark Pace at mpace@timesfreepress.com or 423-757-6659. Follow him on Twitter @themarkpace and on Facebook at ChattanoogaOutdoorsTFP.

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