By STEVEN NALLEY
Jason Wooten of Pepper-Wooten Engineers and Surveyors presented and proposed multiple alternatives to resolve stormwater drainage issues on Maple Drive and Carver Drive during Tuesday’s board of alderman meeting.
Wooten’s presentation was a result of a hydrology and hydraulics study of drainage systems on the two streets commissioned by the city. Wooten said both systems did not have the capacity for 100-year storms, a term assigned to a level of flood water with a one percent chance of being equaled or exceeded each year. A 25-year flood, then, has a 4 percent chance of happening each year, and Wooten said the Maple Drive drainage system does not even have the capacity for that.
“From a design standpoint we can understand not quite being (prepared for) a 100-year event, but 25 is an eye-opener,” Wooten said.
Wooten presented two alternatives for mitigating the overflow of stormwater on Maple Drive.
First, he said, a new storm sewer could be installed behind houses to the south of the street. This plan allows for greater capacity than the second, Wooten said, and its construction would not interfere with traffic on Maple Drive itself or utilities for its residents. The drawback, he said, is the city would have to acquire easements from the property owners south of Maple Drive.
Second, Wooten said, the existing stormwater system could have its capacity boosted. While the city would not have to acquire property for this solution, it would interfere with utilities and traffic, and result in less capacity than the first proposal.
City Engineer Edward Kemp said the first plan would be cheaper by as much as $150,000.
When Wooten said the second proposition for Maple Drive would call for removal of a 36-inch culvert acting as a choke point in the system, Maple Drive resident Susan Shappley said the system had been flooding since before that culvert was installed. She then apologized for interrupting the presentation.
“My house has flooded for 40 years, and I’ve listened to stuff like this for 40 years,” Shappley said Tuesday.
For Carver Drive, Wooten said one of its objectives is to assist the city in obtaining a Letter of Map Revision from FEMA. He said FEMA has to approve any changes to drainageways in flood zones through a LOMR, and that approval has to take place before any actual work on the system is done.
Wooten also said Carver Drive flooding is caused by a choke point in the ditch on Hiwassee Road, where the pipe frequently reaches capacity, leaving water with nowhere to go but Carver Drive. He presented four alternatives for increasing the Carver Drive ditch’s capacity, two of which involve additional pipes alongside the 66-inch pipe currently in the ditch.
Ward 6 Alderman Roy A. Perkins said after the meeting he is still not convinced of the need for FEMA or any other federal agency to get involved with the resolution of flood issues on Carver Drive. He said he believes someone has gotten FEMA involved with the specific intent of bringing progress on Carver Drive to a halt, and he wants the city to accelerate progress instead.
“This matter has been on the table for a very lengthy time,” Perkins said. “The residents of the area have been waiting for years for the pipe to be covered.”