With growth comes the need for new drinking water sources in Marshall County

Marshall County, located outside what was once considered the boundary edge of growing suburbs circling Nashville, has seen explosive growth of its own in recent years — call it the Williamson County overflow effect, says County Mayor Mike Keny.

Drawn by more affordable housing, jobs and the rural character of the county — about an hour from Nashville in the “heart of the Southern Automotive Corridor (as local economic development officials call it) — the influx of residents, and some relocating business and industry, has brought new urgency to a long-standing reality.

The county doesn’t have its own water supply.  For decades, it has had to pay wholesale for drinking water from the cities of Murfreesboro and Lewisburg. That supply is no longer adequate.

A new proposal by county officials calls for building a water treatment facility along the banks of the Duck River in northern Marshall County capable of siphoning up to 6 million gallons of water per day, establish a reliable local water supply for decades to come.

The plan has drawn opposition from environmental groups and the concern of the Tennessee Wildlife Resource Agency over its impact on one of the most biologically diverse sections of the river, a critical habitat for endangered species. Part of what makes the Duck River such a healthy water supply — more than 100,000 people in communities along the nearly 300-mile river depend on it for drinking water —is because it is the most biologically diverse river in the United States, home to 50 different species of mussels and more than a hundred varieties of fish.

At special risk, the Tennessee Wildlife Resources Agency has stressed, are the Pale Liliput and Rabbitsfoot mussels. The mussels often lie near low and flat sand bars that are especially susceptible to shifts in water flow that are downstream from the proposed water extraction point, a letter from the agency to environmental regulators said. Mussels serve as a kind of “water purifier” through their digestive process.

“The particular segment of the Duck River where the new withdrawal is proposed is absolutely critical to the long-term survival of several endangered fish and freshwater mussel species, a fact which requires additional care and transparency in the decision-making process,” a letter to state environmental regulators from Sally Palmer, director of science & policy for The Nature Conservancy, Tennessee said.

The letter notes the group is fully supportive of using the Duck River as a healthy water supply — it currently serves as one for more than 100,000 people at other points in the river — but urges the Tennessee Department of Environment and Conservation, or TDEC, to work with local officials and environmental groups on alternatives.

TDEC has already made the initial determination that the proposal’s impact will result in no significant degradation of the water extraction point. The “de minimus” finding, under state permitting rules, means the agency does not have to go through a more public process of discussing alternatives or undergoing social and economic impact analyses, a process Palmer urged state officials to undertake at an informational meeting last week to hear feedback on the county’s petition for a permit.

“We encourage TDEC to hold a formal public hearing to allow other people who may not have previously been aware about this permit a chance to provide their comments for the record,” Palmer said in a statement last week.  “We also hope that TDEC will help Marshall County and neighbor water utilities with the resources they may need to look at different alternatives to addressing their water supply issues than a new water withdrawal at this ecologically sensitive place in the Duck River.”

County officials say they have already weighed other alternatives that were more expensive and ran into logistical hurdles. An expansion of water capacity at the Lewisburg treatment facility. also located along the Duck River, wasn’t feasible. They looked at purchasing water from Columbia, Tennessee treatment center, but those contract conversations weren’t successful. Water conservation and recycling wouldn’t get the county the water it needs, although officials pledged it would be part of any water plan going forward.

“This is a huge issue for us,” said Keny, elected mayor of Marshall County in 2018. “From the first time I took office, water has been the constant. We’re considered a rural county, no doubt, but as time progresses we get a little less rural. We see more development coming in — we call it our ‘Williamson County overflow’ — but now we’re seeing people coming from all over the country.”