TVA dams holding back water to help prevent downstream flooding

by Dick Byrd, published in The Daily Times 6/3/2-11

As East Tennessee and much of the South mourn the storm deaths and clean up the tornado damage, a new major problem is beginning. This one is a flood — a big flood that could reach historic proportions in some areas along the Mississippi River and its tributaries. It could be an even worse flood except for the work done by The Tennessee Valley Authority.
A combination of snow melt and ongoing heavy rain has worked to make the mighty Mississippi swell beyond its banks. Flooding is also a big problem on the Ohio and Arkansas Rivers, themselves major rivers that also happen to feed into the Mississippi. And it isn’t close to being over yet. Emergency officials in Shelby County estimated that 5,300 homes and businesses will likely be affected by flooding as the Mississippi River and its backed-up tributaries keep swelling. Properties include single-family homes, commercial and industrial properties, and  apartments in at least 17 of the 41 zip codes in Shelby County, which includes Memphis.

The river gauge at Memphis is forecast to read 44.2 feet today. Flood stage is 34 feet, so today’s river level is forecast to be 10.2 feet above flood stage. The river at Memphis is forecasted to rise to 48 feet on the gauge by May 11, or 14 feet above flood stage.

TVA is currently holding back water to help somewhat. TVA’s series of dams was designed to help control flooding as well as make electricity and provide recreation. Draw downs of the string of TVA dams over the past few weeks have helped boost capacity thus allowing TVA’s system to hold back water from recent rains and keep it from entering the Ohio River and eventually the Mississippi.
Barbara Martucci, a spokeswoman in TVA’s Knoxville office, says the TVA series of dams has the capacity to hold back not only the rain from last week but expected rains for the coming weeks. She adds only Kentucky Lake, the huge lake near the mouth of the Tennessee River, is near capacity. Current forecasts indicate no flooding expected farther up the river. The ability of the many dams upstream to hold back water will continue to help the situation in Missouri, Kentucky, Arkansas, Tennessee, Mississippi and Louisiana.
Fringe benefits
TVA has been releasing impounded water from its dams for weeks in anticipation of the Mississippi River flood. Much of that release has been flowing through the turbines creating an abundance of electricity, enough that TVA’s coal and nuclear plants were able to hold back some on production.
TVA has already reported that extra hydroelectric output provided more “green days” of reduced air pollution. TVA officials say such draw downs also allow them to move the warmer top water, revealing the cooler water beneath which is welcome to swimmers and boaters as the recreation season gets under way in East Tennessee.
The flood along the Mississippi is already causing major problems. Homes have been evacuated and more evacuations are expected. Casinos in Tunica, Miss. are closed. Some roads are already closed in Memphis and rural areas along the river and side streams.
The Corps of Engineers had to blow a levee on the Mississippi not far from Cairo, Ill. to relieve pressure on flooding in that area, a controversial move that took some time in federal court to resolve. That operation is flooding what is called the Bird’s Point-New Madrid Floodway.
The big Memphis In May World Championship Barbecue Cooking Contest scheduled for Sunday along the Memphis riverfront has been moved to the old fairgrounds about three miles east of the river.
Down river in places like Natchez, Miss., the river is just now beginning to be a major problem. But the crest expected at Natchez on May 20 is forecast to be 17.5 feet above flood stage, the highest on record, and that includes the disastrous flood of 1927.
More rain is expected over parts of the already-flooded areas along the Mississippi River in the next 10 days and the National Weather Service flood advisories for such places as Memphis and Natchez use this term to describe how long the flood crest is expected to last: “UNTIL FURTHER NOTICE.”
Maryville and much of East Tennessee can expect scattered thunderstorms again next week. But that rainfall, and last week’s heavier rain, is no match for the holding efforts of the Tennessee Valley Authority. Residents downstream on the Mississippi River can at least be thankful for that.
The Associated Press contributed to this story.