Freezing Temps May Reduce Water Weeds

Winter is whacking the water weeds. And that’s a good thing for those who need access to TVA’s reservoirs for summer recreation.

JANUARY 19, 2017—Recent bitter cold temperatures across the Tennessee Valley may cause some people to worry about their plumbing, but for recreational boaters and swimmers who battle water weeds in area lakes, the deep freeze has been a good thing.

“Mother Nature is the best aquatic plant management tool we have,” says Brett Hartis, PhD, TVA’s lead aquatic plant biologist. “Many invasive plants cannot handle extended deep cold snaps like we’ve seen so far in January.”

According to TVA load forecasters, 2018 started off very cold—in January TVA reached near record power demand because the average temperature has been below freezing for 10 days thus far.

To meet the power demand, TVA has relied heavily on hydropower, dropping some reservoirs—like Melton Hill—by about two feet below what people normally would expect.

A Good Year Coming

“The last few winters have been very mild and we’ve seen an increase in aquatic plant growth,” says Hartis. “The lower waters levels expose invasive plant beds to the cold, and most invasive species can’t tolerate the cold like native plants can. While there are no guarantees, Mother Nature should help this summer’s boaters and swimmers by controlling invasive plants in exposed areas along the shoreline.”

Keeping the reservoirs healthy is a top priority for TVA. According to a 2017 University of Tennessee study, recreation on Tennessee River and its reservoirs is worth about $12 billon to the local economy and creates about 130,000 jobs each year.

TVA manages aquatic plants in developed public-access areas on its reservoirs on an as-needed basis when recreational use and/or access become seriously hindered. Homeowners may control aquatic plants along their property as long as they follow all state herbicide application laws.

Hartis will know how effective Mother Nature has been this spring: “We are expecting to see a significant visible reduction in new growth along the shoreline.”

Fishermen Don’t Worry

TVA reservoirs are recognized around the nation for its prime sport-fishing lakes. Hartis, an avid angler himself, knows the positive aspects aquatic plants have on reservoir fish habitats.   

“Don’t worry,” says Hartis. “The winter weather will only affect shoreline plants where the plant bed is exposed to the cold. Submerged plants like hydrilla are not affected.” 

Hartis muses that some of his secret fishing holes may have to change this summer. But then that’s all part of the fun. “Good fishermen can easily adjust,” he says. “That is why they call it fishing and not catching.”

Bottom line, Hartis expects that access will be much improved, and that he and other anglers will still be able to pull monster-size fish out of the reservoirs this summer. 

How You Can Help

TVA needs your help to control aquatic plants and keep invasive species out of our reservoirs. To help control invasive plants, Hartis recommends:

  1. Keep it clean—Remove all plant material from boats, trailers, bilges, live wells and any marine equipment. This will prevent aquatic species from being introduced into other TVA reservoirs.
  2. Native water gardening only—Plant only native species around shorelines. While non-native species like ornamental lilies and water hyacinth are beautiful, they will quickly spread if introduced into the river.
  3. Drain and dry—When visiting reservoirs with known invasive plants, make sure all equipment is dry and free from fragments. Even completely dry fragments have the potential to grow once submersed again. Consider visiting non-affected reservoirs only after you have cleaned, drained and dried your boat.
  4. No dumping please!—Refrain from dumping unwanted aquarium or water garden plants into nearby streams and rivers. Dispose of any unwanted plants in the garbage.

Guide to Aquatic Plants

Loved by fishermen, aquatic plants—or weeds, as they're known—provide cover for predatory fish, such as bass. Here's how to tell them apart, how to fish them and how to understand when and why they need management