As NOLA braces for Hurricane Rita’s rains, praying its damaged levees will hold — and Rita’s rank has been upgraded from fifth to third place as the most powerful storm in history — it’s still important to look ahead to possible solutions. Tomorrow’s Wall Street Journal (sub.only) critiques “supersizing the levees,” declaring:
“Protecting New Orleans from future hurricanes will cost billions … “send swarms of bulldozers into swank neighborhoods (PHOTO above),” blocking views … “threaten environmentally vulnerable marshes, and trigger lawsuits from homeowners whose property would have to be seized to make room for the supersize levees.”
The WSJ’s companion piece, “Other Ways to Deter Floods,” lists a number of alternatives to earthen levees — some realistic, some not … from gates to bladders … details BELOW:
Earthen levees aren’t the only way to hold back water. Here are some alternatives proposed or already in use in other countries:
Barriers: After a 1953 flood killed nearly 1,900 people, the Netherlands embarked on a 40-year, $8 billion project called Delta Works, a network of sluices, dams, levees and barriers. One of its most ambitious projects is the Maeslant barrier, an enormous moveable sea wall completed in 1997 to protect the port of Rotterdam. When a computer model predicts a dangerous storm surge, the barrier, which is operated by two arms nearly the size of the Eiffel Tower, can close off the North Sea from the main shipping lane into Rotterdam. So far, the barrier, which sits 10 feet higher than sea level, hasn’t been needed.
Gates: After years of political and environmental debate, Italy is installing a system of gates on the bottom of the Adriatic Sea to keep out rising tide and prevent Venice from flooding. The panels are to be filled with air to make them rise. Engineers say they would be impractical on the Gulf of Mexico, however, because so many would be required and because they are designed to hold back additional water from high tides, not walls of water from hurricanes.
Bladders: Some vendors sell tubes encased in a hard plastic shell that can be filled with water, even floodwater, and used to hold back a storm surge. These devices work best, floodplain managers say, as temporary measures to protect individual buildings or to dam off small bodies of water.
Geogrids: Some engineers favor expanding existing levees with a type of super dirt, reinforced with a synthetic polymer made of a petroleum byproduct. These “geogrids” create a strengthened soil that has been used to build roads on weak ground and retaining walls.
Smart concrete: Other engineers propose coating earthen levees with a protective, two-foot shell of concrete with the ability to sense when a breach or other structural damage occurs. Such “smart concrete” contains electronically conductive carbon fibers that can measure stress from a remote location.
