How TVA Reduces Flood Damage
The best time to reduce the impact of a potential flood is before it starts, right? Thats exactly what TVA tries to do.
TVA uses 35 dams to reduce flood damage by holding back the water from heavy rains in reservoirs. These flood-storage reservoirs (usually located on tributary riversrivers that run into the main Tennessee River) do most of the work in controlling floods.
|Before TVA, flooding plagued the Tennessee Valley in late winter and early spring.|
The big storms that can cause flooding are most likely to hit the Tennessee Valley in the winter and early spring. So, to make room for this water in the flood-storage reservoirs, TVA lowers their water levels by Jan. 1 each year. The water in tributary reservoirs can rise and fall as much as 60 feet per year.
When a storm hits, TVA holds back the water by closing the gates of dams in areas where it is raining. When the rain stops and the danger of downstream flooding is over, TVA lets the water out at a gradual rate to get ready for the next storm.
As you might expect given how much it rains, there were lots of floods in the Tennessee Valley before TVA dams were built. These floods washed away the topsoil, causing problems for farmers. Even worse, hundreds of people died and thousands more lost their homes and farms. The city of Chattanooga, Tennessee, would flood about once a year. Click here to find out why.
In an average year, TVAs system of dams and reservoirs now prevents about $240 million in flood damage along the Tennessee, Ohio, and Mississippi Rivers.
...how much water it would take to wash a car away? Click here for the answer