Harpeth River Put on Endangered Rivers List

The Harpeth River made the America’s Most Endangered Rivers list for 2015, highlighting the threat sewage pollution and excessive water withdrawals pose to clean water and public health. The list is put together by the American Rivers conservation group.

The fear for the river is based on the fact that if more sewage water is being discharged into the river without proper dilution, then it would cause too much oxygen-sucking plant life, such as algae, to grow in the river in order to naturally clean the water. Since algae and fish and other things in the river ecosystem need to share the oxygen, too much waste-cleaning algae is bad news for a river ecosystem.

The Harpeth River flows through the heart of downtown Franklin, the 14th fastest growing city in the United States, and traverses the county, which is one of the fastest growing counties in Tennessee. Rapid development has already impacted the river with treated sewage and water withdrawals. The City of Franklin will soon be making choices that may greatly affect the outcome of the future of the Harpeth’s ecosystem.

“The Harpeth River and its tributaries are home to rich freshwater biodiversity, including more than 50 species of fish and 30 species of mussels. Several of these species are classified by Tennessee as rare and in need of management, and two mussel species are protected under the Endangered Species Act,” says the American Rivers website.

Water pumps in Franklin draw drinking water from Harpeth
Water pumps in Franklin draw drinking water from Harpeth

Nitrogen and phosphorus are also on the list of chemicals that endanger river ecosystems. These chemicals enter the river from sewage plants, but also enter the river from stormwater runoff in places like agriculture fields and parking lots.

The City of Franklin has not been found to be in violation of any state regulation, but as development increases more people means more wastewater that has to be handled by the sewage plant. As new permits are issued by state regulatory agencies, Franklin will have to meet the demands by incorporating new technology to reduce nutrient pollution harm to the Harpeth River.

“From the standpoint of the sewer system and the sewer plant and growth, the city analyzed growth, how much they needed to process sewer for growth. And they want to double the size of the sewer plant from 12 to 24 million gallons per day,” said Dorie Bolze, Executive Director of the Harpeth River Watershed Association.

Franklin’s website states that their water reclamation facility “consistently outperforms the regulatory limits set by the Tennessee Department of Environment and Conservation.”

Also according to Franklin’s website: “The City is evaluating the potential for a second Water Reclamation Facility to accommodate the growth the City of Franklin is experiencing utilizing the most economically feasible alternatives for our customers and citizens. If a new Water Reclamation Facility is deemed the most economically feasible alternative, a high level of advanced treatment will be implemented to ensure high quality effluent is entering the Harpeth River that will be safe to all users.”

Franklin's sewage treatment plant courtesy of Google Earth
Franklin’s sewage treatment plant courtesy of Google Earth

All wastewater doesn’t have to go to the river, according to Bolze. Some of it is pumped out to water golf courses and some is used for other irrigation, so expanding the plant doesn’t necessarily mean more pollution in the river.

Bolze also pointed out that Franklin uses a guage for the river that is set downstream of the sewage plant, which gives a false reading to how much water could actually safely be pulled from the river because the wastewater has been pumped in before the readings are taken.

“There’s enough error in those readings that in the summer they could be pulling water from the river when there really isn’t water to be pulled,” Bolze said.

The Environmental Protection Agency put a plan together for how much the river can handle and still meet the state standards. As it stands, the Harpeth River in many places, not just Williamson County, will not meet the new standards once a revised permit is issued. The state’s environmental division, TDEC, asked sewage plants to find a way to optimize how they work to pull out more nitrogen and phosphorus because the next round of permits will have tighter limits.

“All of this is about designing the sewer plant that they’re working on to ensure that it removes, cost-effectively, phosphorus and nitrogen. Some of that is just adding an extra treatment system. We know that [the new permits] are coming, and all the data indicates that there is an algae problem in the river. That’s why it’s such a big deal,” Bolze said.

Endangered species photo courtesy of harpethriver.org
Certain mussels are an endangered species living in the Harpeth. (photo courtesy of harpethriver.org)

Over fertilizing rivers is actually a national issue, and the sewer plant in Franklin is only one of the things causing red flags for the Harpeth River. For Franklin, it’s based on the fact that during low times in the summer there may not be enough water in the river to dilute the sewage without causing too much algae to grow, which unbalances the river’s ecosystem. As they say, the solution to pollution is dilution.

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