published Tuesday, May 20th, 2014

The cost of pollution: Raise the levee and man the rowboats

Raising a wall of the Brainerd levee is the kind of thing we'll likely see more of as climate change transforms our planet.

In fact, we're already seeing it.

After Hurricane Sandy, FEMA revised its flood zone maps, placing twice as many homes and businesses in and near New York City in flood-zone areas. The new reality is forcing those property owners to buy flood insurance. New York officials last year recommended a $20 billion flood wall, and a new analysis released this month from Dutch and American researchers says a massive seawall there may be the most cost-effective way to control severe flooding from future Sandy-like storms.

Even here, we already see other adaptations from potential future mothers-of-all-floods.

TVA in 2009 announced it would spend about $8 million on temporary sand and gravel baskets to raise the embankments around four dams above Chattanooga by 3 to 4 feet. Some months later, TVA also said it was spending at least $17 million on retrofits at Watts Bar and Sequoyah nuclear plants to prepare for higher flood threats.

Like the questions around why the Brainerd levee isn't as tall as it should be to withstand future floods, TVA's improvements to the Watts Bar, Fort Loudoun, Tellico and Cherokee dams also were partly a look beyond modeling mistakes and changing technologies and a look ahead at changing weather patterns.

TVA found that early modeling for its dams and nuclear plants had not accounted for changes in river management and had not accounted for lower than anticipated outflows from some spillways. The utility -- at the Nuclear Regulatory Commission's behest -- also was looking ahead at new potential water and weather threats, especially in light of concerns following Fukushima's reactor meltdowns after an earthquake and tsunami in Japan.

Now the same is true for the Brainerd levee. When the levee was designed, there were no modeling inputs for flows from Spring Creek, which, along with South Chickamauga Creek, puts flooding pressure on Eastgate and North Brainerd. Now new modeling for Spring Creek is introducing a variable that wasn't counted on when the 3.8-mile levee was completed in 1981 along the South Chickamauga Creek after the area was left under water in a 1973 flood.

The larger question is whether the new and emerging threat of climate change is being fully factored in, rather than just weather events of recent history like the hurricanes Sandy and Katrina.

For instance, a University of Tennessee at Knoxville researcher in 2012 completed a first-of-its-kind study to predict heat waves for the top 20 cities in the eastern United States. His findings put the Tennessee Valley in the cross-hairs of climate craziness with a likelihood of more intense heat waves and -- more to the point -- drastically wetter weather.

For this region he predicted as much as 17 inches of extra annual rainfall.

Last year, that's just what we got: Our normal 52.5 inches of rain plus another 16.29 inches totalled nearly 69 inches of rain for 2013, according to the National Weather Service.

Fortunately, it didn't all fall in a short period -- that time.

Chattanooga is bidding a construction project to add height to the levee's 600-foot-long secondary flood wall near Spring Creek. It will also make a contingency plan in the event of flooding along Interstate 24 and raise a berm around nearby pump stations, according to Lee Norris, the city's public works director. The result is expected to cost city taxpayers an estimated $500,000.

The alternative is some 3,000 homeowners watching their flood insurance bill go sky high.

Should there be homes and businesses in areas that might flood? That's a debate we should have, but for now, people do live and work is areas prone to flooding, and we can't very well just evict them. (Parkridge East Hospital, for instance, had to ferry patients into the hospital in rowboats and on all-terrain vehicles during a 2009 flood.)

For now, our alternative is to raise the levee and man the rowboats, because neither the public nor Congress seems intent on changing how we tax carbon emissions -- the pollution we put in the air that fuels the pace of climate change.

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Plato said...

Pam - you have to understand that $14.58 per month per household that would result from Cap & Trade would be devastating to the economy. We just can't afford it :)

May 23, 2014 at 7:45 p.m.
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