New maps highlight vanishing E. Shore

Coast: Technology provides a stark forecast of the combined effect of rising sea level and sinking land along the bay.

July 30, 2004|By Tom Pelton | Tom Pelton,SUN STAFF

Richard A. White wants to live the rest of his life in his waterfront home, which perches at the tip of a filament of land reaching out into Chesapeake Bay and boasts a 50-foot-long veranda with panoramic views of the sunset.

It sounds idyllic. But the 60-year-old historian has to drink bottled water because salt water has ruined his well. Whitecaps often froth across his lawn, which has shrunk by about 40 feet in the past 18 years.

And during high tides in the fall, he pulls on tall boots, parks his car a block away on high ground and ties a rowboat beside his door, as his century-old house becomes a tiny island unto itself.

His property on Maryland's Eastern Shore is a vivid example of what is happening in low-lying areas all around the Chesapeake Bay, as rising sea levels coupled with slowly sinking land threaten to wash away homes, roads and farms some years down the road.

Scientists have long known about this trend, which already devours at least 260 acres of coastal land in Maryland every year.

But the urgency of the problem has been highlighted recently by a new mapping technique that uses laser beams aimed from airplanes to measure the height of land masses.

The highly accurate topographical mapping, being pioneered by the state and federal governments, could revolutionize planning for storms, development and flood insurance on the Eastern Shore and elsewhere, officials say.

It's also worrying local officials who have seen the first of these maps and who fear that dire predictions of future land loss will discourage development and home buying.

A psychological thing

"Most of the county councils on the Eastern Shore don't like to hear about sea-level change. It's a psychological thing, and they're worried about it impacting property values," said J. Court Stevenson, professor at the University of Maryland Center for Environmental Science.

"It's a conundrum. There is a tremendous real-estate boom in Dorchester County right now, but there are also a tremendous number of acres that are going to be under water.

"A lot of wealthy landowners have land that will be submerged, and they would like to sell it before then," he said.

Dorchester, where White lives, has received some of the first such maps from the state Department of Natural Resources and U.S. Geological Survey.

The maps show much of the county's southern quarter being consumed by water over the next century. Projections based on both conservative and moderate global-warming estimates show vast sections of wetlands in the 26,000-acre Blackwater National Wildlife Refuge being flooded.

Scientists developing the maps, sensitive to the potential impact of their predictions, are offering two scenarios for each area: a highly conservative forecast, based on the continuation of the historical rise in sea level of 1 foot over the past century, and a moderate "global-warming" scenario, projecting a 2.25-foot rise by the year 2100.

Not the movies

"We are desperately trying to avoid being associated with The Day After Tomorrow," said Curtis E. Larsen, a research geologist with the U.S. Geological Survey office in Reston, Va., which is helping the project in Maryland. Larsen was referring to the movie in which tidal waves crush New York City.

"We want people to know this is real," Larsen said. "There is fully one-half of the population that doesn't believe this is happening at all, and so we have to show them a business-as-usual scenario as well as a global-warming scenario."

On the narrow Middle Hooper Island peninsula, the conservative projection would show the main road being washed out, new inlets breaking through and houses, including White's, being flooded. If the waters were to rise by 3 feet, which some scientists predict, the whole island would disappear by 2100, with all but a few isolated peaks under water by 2050.

"It's pretty dramatic. A 2-foot sea rise would pretty much inundate all of south Dorchester County," said Robert Tenanty, county engineer. "It's something we are aware of - and we need to take steps now, because it's only getting wetter."

Although debate continues over the future rate of global warming, very few scientists dispute that it's happening and that sea levels will rise by at least a foot over the next century in the Chesapeake region - a rate significantly faster than elsewhere in the world.

An international committee of more than 1,000 scientists, called the Intergovernmental Panel on Climate Change, projected in 2001 that sea levels worldwide will rise by roughly 1.6 feet by 2100, with a range of possibility from 4 inches to almost 3 feet.

Each foot of rise can mean at least 10 feet of land disappearing along the shore - and sometimes many times this amount, depending on the land's slope, said Stevenson of the University of Maryland.

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