Tennessee lawmakers are considering a bill to remove protections for certain types of wetlands across the state to financially benefit developers.
The bill is on the schedule for debate this week with a new amendment. 
The original bill would have cut all regulations for development related to “geographically isolated wetlands,” a misnomer for wetlands connected to bodies of water through groundwater or storms. The sponsor of the bill, Rep. Kevin Vaughan, R-Collierville, is a developer and was associated with a development project in 2019 that illegally drained and filled a wetland.
The amendment still proposes deregulating the vast majority of isolated wetlands, removing protections for isolated wetlands less than two acres in size.
Isolated wetlands hold flood waters, filter pollutants–including forever chemicals–provide habitat and recharge streams, rivers and aquifers. Clusters of small wetlands can greatly reduce flood impacts. For these ecological services, a single acre has been valued at nearly $50,000.
In Tennessee, about 94% of the state’s individual wetlands cover less than two acres, according to the Tennessee Department of Environment and Conservation’s new data screening tool. The department hired a company to create a model that uses LiDAR elevation data and machine learning to identify areas where wetlands are expected to occur across the landscape — an analysis only possible due to recent improvements in artificial intelligence, according to Ryan Jackwood, the director of watershed science at the Harpeth Conservancy.
“It took them several weeks of straight computing to come up with this data set,” Jackwood said.
The model predicts that Tennessee has more than 400,000 distinct, isolated wetlands. Most are tiny, while some may be up to 300 acres in size. (In terms of just sheer acreage, the proposed legislation would affect up to nearly half of the state’s total isolated wetlands.)
The legislation is worded strategically to limit environmental regulations based on common development scenarios, such as developers finding groups of isolated wetlands on properties.
For example, if a developer plans to build on a 10-acre plot of land, they would normally add up the total acreage of the existing wetlands in order to determine how much they would pay for mitigation. There could easily be several acres, cumulatively, on a 10-acre plot. But the new amendment removes what’s called “cumulative impact analysis,” so developers would only have to consider each wetland individually. So, if each wetland is small, then developers could drain, fill and build over wetlands at no cost.
This would also be true even for sprawling developments.
“The bigger the plot of land, the bigger the development, and the more small wetlands on it, it wouldn’t matter,” Jackwood said.
In other words, developers could do a lot of damage with serious consequences.
The amendment also divides up regulations related to current state definitions of low-, moderate- or high-quality wetlands. But the scientific understanding of the ecological value of wetlands is evolving each year.
“There is likely no large difference in hydrologic function between low- and high-quality wetlands. Even low-quality wetlands serve hydrologic functions such as flood control and recharge,” reads a TDEC report from September.
The bill is scheduled to be heard by the House Agriculture and Natural Resources Subcommittee on Wednesday.
