Cookeville will update its stormwater management program in accordance with changes to federal regulations passed down by TDEC.
Cookeville Public Works Director Mary Beth Elrod said Cookeville began its program in 2004 upon receiving MS4 designation due to its population and density. She said the changes encourage eco-friendly stormwater management for commercial developments.
“Ponds and stuff we see built in commercial developments, they see that there’s room for improvement there,” Elrod said. “So, that’s why they’re changing these ordinances periodically, to just help the storm system and all of our lakes and rivers. Keeping them clean and keeping us sustainable so that we can keep growing.”
Elrod said TDEC updated regulations in 2022 and gave the city two years to implement the changes. Cookeville City Council will hold a public hearing Thursday.
She said developments have been required to retain and treat one inch of rainwater to remove sediment and grime. She said this adjustment is more stringent, involving a tier system that requires developers who opt for cheaper stormwater systems like ponds to treat up to three inches of rainwater.
“Depending on what the commercial development chooses to build and construct will define how much water they have to treat,” Elrod said. “So, if they decide to just stay with ponds like we traditionally see, they will be having to build bigger ponds to treat a higher volume than we have seen in the past.”
The update also tightens up the program’s requirements for riparian buffers, which refer to the buffer developers have to keep with streams and wetlands that they release water into, presently set wet between 30 and 60 feet. She said now, developers can no longer run pipes over the buffer and release water into the streams. Instead, water must be returned to sheet flow before reaching the buffer.
“They have to build ponds and detain that water and slowly release it because pavement releases water a lot quicker than a grass lot would,” Elrod said. “So we control commercial development on their quantity of water by detaining it and slowly releasing like it was still a grass area.”
She said the city’s erosion control ordinance will not change much. She said during the construction period, developers will still be required to have a stormwater pollution prevention plan designed to keep dirt and sediment from escaping the property. She said these plans require black silt fences and monitoring of entrances to keep trucks from tracking dirt onto city streets.
“This is nationwide and all states are required to do this,” Elrod said. “So, TDEC has passed this down to us and they have seen, since the past 28 years that this phase 2 MS4 program has been in operation, they have seen some weak points in it or some areas that could use improvement. Most of the improvement is on these permanent storm systems like ponds and stuff we see built in commercial developments.”