In drafting plans for flood control, waterway navigation and other water-related projects, Army Corps of Engineer designers must tailor plans to meet the demands of rising sea levels, according to a new policy. In the simplest terms, that means that a levee, for example, may need to be designed higher than it would have been previously.

Among the Army Corps’ water-related projects are dredging for waterway navigation, the design and construction of dams and canals, and the design and construction of levees and other flood protections. Sometimes those flood protections fail. The agency was blasted by some of the country’s leading engineers, scientists and the general public in the days and months following Hurricane Katrina, when the levees collapsed in New Orleans. As Greenwire’s Taryn Luntz reports, Army Corps officials say that the new policy is a response to that failure.

The change in policy acknowledges the science that projects sea level to rise between seven and 23 inches by the end of this century, with the possibility of rising up to three feet. It also acknowledges that low-lying coastal regions are especially vulnerable. It is the Corps’ coastal engineering projects that make it possible for shoreline development to take place, and towns and cities to arise along America’s coasts. But now factoring in sea level rise, some of those projects - especially those in the lowest-lying coastal regions - could become less attractive to the agency.

Though the new policy has the potential to be more expensive on the front end, Luntz reports that senior Corps officials expect it will save the agency the difficulty of having to redo a project, or even the possibility of having to undo one. The policy states that Army Corps planners must consider the following three circumstances:

1. At the very least, estimate how historic rates of sea level rise might affect a project
2. Evaluate sea level rise rates predicted by the UN Intergovernmental Panel on Climate Change (IPCC)
3. Consider a higher rate of sea level rise than what the IPCC has predicted, as the panel has been criticized for underestimating rates

In the past, the Corps has not ignored the reality of sea level rise, but similar to public opinion of the recent past, climate change-related effects were not taken as seriously as they are today. The Corps has had a planning policy for sea level rise for over 20 years. But the old instructions were very short and buried among lengthy documents. The new policy, released in July, is a separate, 44-page document.

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