TVA dams and reservoirs help to “keep floods away from the people,” but they cannot prevent all flooding. For this reason, TVA also tries to “keep the people away from floods” by promoting the wise use of floodplains and preventing development that can adversely impact operation of the reservoir system for flood damage reduction purposes. (Floodplains are lands bordering rivers and streams that are normally dry but are covered with water during floods.) The focus is on the lands and projects TVA holds in stewardship and on the floodplains along the rivers and streams regulated by TVA dams.

A key component of TVA’s floodplain management effort is promoting awareness of flood risks. TVA uses historic data to determine which areas fall within the 100-year floodplain. People living in these areas have a 1-in-100 chance of being flooded in any given year (which is different from being flooded once every 100 years). Essentially, this means that if they choose to build there, they do so at their own risk.

Section 26a of the TVA Act gives TVA control over structures built out into the waterway that could impact flood damage reduction, navigation, and public lands, such as docks and marinas. (Learn more about TVA’s shoreline construction permitting process.) But TVA does not have regulatory authority over structures in the floodplain. The responsibility for implementing and enforcing floodplain zoning resides largely with local governments.

As part of its floodplain management effort, TVA demonstrates innovative ways to reduce flood loss. In some cases, flood-warning systems offer a solution. These vary in design from simple to elaborate. A simple but effective warning system consists of a stream gauge with electronic sensors that monitor water levels at an upstream location and send an alarm by telephone or radio when a predetermined flood level is reached. The more complex systems typically rely on computer forecasting models that predict stream flows and potential flood heights.

Did you know?

TVA’s reservoir system regulates less than 10 percent of the total stream miles in the Tennessee Valley.

In some cases, local communities along unregulated streams can reduce their vulnerability to floods using structures such as dikes, levees, and floodwalls; channel modifications; high-flow diversions; onsite detention; and other traditional flood mitigation methods.

But reducing flood damage in these areas depends primarily on accurate flood risk information, appropriate siting of new development, effective warning systems, emergency preparedness planning, and public education and awareness.