The Duck River

Tennessee’s environmental agency, the Tennessee Department of Environment & Conservation (TDEC), is asking for public comments on a series of proposed and expanded water withdrawals (by drinking water utilities) from one of the most biodiverse rivers in the world—the Duck River—which flows through Middle Tennessee.

These withdrawals will pull water from parts of the river designated as scenic and Exceptional Tennessee waters, and they add up to an estimated 35% increase in one of the fastest growing areas of the state . . . but the Duck isn’t getting any bigger! We want to see a long-term, science-driven plan for this area that can both protect the Duck while also ensuring safe, reliable drinking water for local communities as they plan for growth.

Photo: Higher Pursuits

In early 2024, Harpeth Conservancy (HC) provided our analysis on the first of seven draft water withdrawals proposed by TDEC for the upper Duck River. In those comments, we thanked TDEC for coordinating utilities’ withdrawals along the river, but we also pointed out that state permits shouldn’t let communities take too much water without having to prove that the river, endangered species, and downstream communities will also have enough clean water.

We commend TDEC for beginning a regionalized, coordinated, and adaptive approach to managing the Duck River for multiple uses. Balancing development pressures with pollution prevention is tough, but it’s doable…and necessary. And coordination is important because waters have many beneficial uses: drinking water, wildlife habitat, irrigation for farms, water for livestock, recreation and fishing, electricity generation, and the general enjoyment that comes from being outdoors.

HC therefore supports the agency’s decision to require water withdrawal permits for the Duck as it supplies drinking water for over 250,000 (and growing!) Tennesseeans. We also support the agency’s decision to set limits on how much water may be withdrawn during certain low-flow conditions.

These are good first steps. However, Harpeth Conservancy is concerned that the permits aren’t yet sufficiently protective. Permits can’t authorize pollution or degradation caused by withdrawing water without stepping through some important hoops, including looking at alternatives and making sure that the balance is right between economic development and healthy waterways. Because of our concerns, HC is asking that the permits be revised.

Why Harpeth Conservancy Wants TDEC to Strengthen the Permits​

1. The Duck River is incredibly special!

The Duck is one of the most biodiverse rivers in North America, providing habitat for dozens of threatened aquatic species, plus an impressive variety of all freshwater species (151 fish, 56 freshwater mussels, 22 aquatic snails, and at least 225 types of aquatic insects, crustaceans, and worms)—the Duck supports over 650 aquatic species; that nearly a quarter of all mussel species in North American are native to the Duck River! And mussels aren’t just living proof that a river is healthy—mussels like the Birdwing Pearlymussel, Cumberland Monkeyface, and Duck River Dartersnapper help keep rivers clean by filtering pollutants as they filter their food from the water.

People who live, fish, and recreate along the Duck know first-hand that these stats can’t tell the whole story: this river is special because of the stories and memories passed on generation-by-generation.

TELL TDEC what makes the Duck River special to you and why the agency needs to revise the draft permits before they are issued!

2. The permits don't adequately recognize that the Duck River experiences regular low-flow conditions in the summer.

The Duck River is a low-flow river for significant portions of the year. While there is a relative abundance of water during the winter season, these permits would allow the utilities to pull large amounts of water year-round, even when the river is experiencing low flows. For example, 150 miles of the Duck are critical habitat for the 20+ species identified as endangered or threatened, meaning there has to be enough clean water in the summertime for both utilities’ needs and the vulnerable species.
HC wants the draft permits to be strengthened because the drafts don’t expressly recognize that utilities’ requests for ever more water is unsustainable, and more information is needed about the minimum amount of flow that should be left in the river. After all, our water supplies are already under stress from changing weather patterns and more frequent extreme weather events, which is often when water demand grows.

ASK TDEC to establish preliminary low-flow cut-offs now, not in five years.

3. TDEC isn't requiring the utilities to maximize their conservation efforts or minimize their water loss.

TDEC can condition these water withdrawal permits on best-in-class conservation requirements and efforts to reduce water loss from the pipes that make up drinking water transmission systems. For example, all water systems “lose” some water through leaking pipes, but utilities need to patch up their pipes because leaks add up: letting these utilities lose up to 25% of what they withdraw . . . adds up to millions of gallons a day that should be in the Duck!

The Duck—like all waters that flow through Tennessee—are held in the public trust. Rivers are a public resource, and utilities that ask permission to take water out of rivers need to be the best stewards possible for that water. This means that utilities need to detect, prevent, and remedy water loss and inefficient water use throughout their systems.

In an ideal world, water wouldn’t be wasted, but these permits need to limit loss to 15%, a reasonable industry benchmark, and then establish plans to keep doing better.

Photo: Higher Pursuits

ASK TDEC to add mandatory conservation measures to the permits and establish Duck River-specific water loss measures, no more than 15%.

4. TDEC must require ecological flow studies to learn how best to protect the Duck.

Photo: Higher Pursuits

Studies are needed (and overdue) to determine the minimum amount of water that must be left in the Duck to meet water quality standards, which are one way the state manages various uses to keep the river and the critters that depend on it healthy.  All utilities need to participate in and conduct these studies.

Studies to determine the Duck River’s ecological flow needs are essential, and they should be conducted in coordination with, at minimum, the U.S. Fish and Wildlife Service, the Tennessee Wildlife Resources Agency, the U.S. Army Corps of Engineers, the U.S. Geological Survey, the Tennessee Valley Authority, and non-governmental experts. Harpeth Conservancy isn’t new to this issue: we’ve gained expertise over the years by working on water withdrawal permits that balance utilities’ needs with science-based resources management requirements.

We believe the agency will need to re-open the permits to adjust the withdrawals limits once ecological flow studies and other studies have been completed. After all, even at the current withdrawal rates–much less at the increases all the utilities are proposing–there is evidence that mussel populations in key areas with endangered species are being “stranded” when the river levels are too low. That suggests the balance is off. Harpeth Conservancy is optimistic that TDEC can balance public water supply needs with all the other ways the Duck is special, including protecting its extraordinary biodiversity.

ASK TDEC to require the permittees to conduct studies to determine the Duck’s ecological flow needs before the next permit cycle.

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