Aquatic plants, whether invasive or native, can be described as either a mess or a resource. Natural plant growth covers 20 – 40% of the water and includes a diversity of plants. However, invasive plants such as Eurasian watermilfoil, hydrilla and water hyacinth quickly take over a lake covering 60% and sometimes 100% of the surface water.
Tennessee Valley Authority is a corporate agency of the United States that provides electricity for business customers and local power distributors serving 9 million people in parts of seven southeastern states. TVA maintains 29 power generating dams with reservoirs in addition to another 17 non-power dams that are used solely for flood control and recreation. TVA is certainly no stranger to invasive species.
Management of invasive plants is necessary to keep the right balance between the diversity and density of plant growth. TVA has been managing invasive plants since the late 1950s, when it began to address the problem of milfoil. In the 1960s, TVA began to use helicopters to chemically eradicate weeds.
One of TVA’s management options is prevention. In some communities the spread of invasive plants have been prevented by quarantining boats on specific bodies of water to prevent transfer.
- Physical management including the use of mechanical weed harvesters or barriers such as plastic to prevent sunlight from reaching the plants.
- Biological methods include the introduction of grass carp to eat the weeds.
- Chemical management includes the use of herbicides to kill the weeds.
- Mother Nature is perhaps the most effective force in managing invasive plant growth. Many of the invasive weeds are susceptible to cold. The past few mild winters in the region might explain the increase of invasive plants on TVA waters.
In a recent workshop on the issue of aquatic invasive species, over 200 people turned out to not only voice their concerns on the growing weed problem, but to learn how they can help in the management.