Countries Are Preparing for Rising Seas But the U.S. Is Far Behind
Continued from previous page
The United Kingdom has wisely divided up the English and Welsh coasts into eleven units of manageable length based on geology (called sediment cells) independent of political boundaries. Shoreline management plans are then devised for each cell. It is widely accepted that all of the shoreline can’t be protected and that houses and even some villages will have to be surrendered to the sea.
Abandonment has been recommended for 25 square miles (65 km2) of the ï¬‚at, low-elevation Norfolk “Broads” along with six villages and ï¬ve small lakes in Norfolk County, East Anglia. Lady Barbara Young, the chief executive of the U.K. Environment Agency, says that between salinization and greatly increased storm damage potential, the sea should be allowed to breach the shoreline, ï¬‚ood the ï¬‚ats, and form a new bay. Coastal experts believe that seawalls would fail to hold back the shoreline here in a time of rising sea level. Most of the villages date from before medieval times, with historic buildings and bridges still standing, making the decision (not ï¬nal yet) most difï¬cult. There already is a long history of ï¬‚ooding in the area, including the record of a 1287 storm surge ï¬‚ood that killed nearly two hundred people in the village of Hickling. A few miles to the north of the Broads, the village of Overstrand, a cluster of 135 houses plus several businesses, will also be allowed to fall into the sea in this century. Abandonment of this area had been considered in 1662 after a great storm. Local citizens objected strongly, and as a result two thousand men were press-ganged to build new dunes—an approach that obviously can no longer work.
The Thames River Barrier, on the outskirts of London, was designed to protect $160 billion worth of buildings and infrastructure in London from storm surges moving upriver from the sea. The gates have been closed 108 times since they became operational in 1982, but since they were designed in the 1970s, the local sea level rise rate has doubled and it is assumed that it will accelerate even more. With a modest rate of sea level rise, the gates may remain useful until 2082, but with an extreme rate of sea level rise, the gates’ capacity may be exceeded as soon as 2020. New design efforts are under way. The Dutch, masters of protection from the ravages of the sea, have sheltered themselves in recent years with a variety of storm surge ï¬‚oodgates similar in function to the Thames River Barrier. The two grandest ones are the gates protecting Rotterdam and those across the Eastern Schelde, the latter of which was not designed with sea level rise in mind. If breeched by a storm surge, a large developed area of the Eastern Schelde River distributary valley would ï¬‚ood. In any event, a signiï¬cant sea level rise of 3 feet (0.9 m) or more will probably negate all of the world’s current storm surge ï¬‚oodgates.
Click here to buy a copy of The Rising Sea
Orrin H. Pilkey is emeritus in the Nicholas School of the Environment at Duke University, author of The Corps and the Shore, and editor of the twenty-volume series Living with the Shore.
Rob Young is the director of the Program for the Study of Developed Shorelines and professor of geosciences at Western Carolina University.