FEMA's new flood plain mapping could cost coastal Mainers dearly

Tux Turkel in the Portland Press Herald (Maine): The seaside ledge where Bob Blackwood's house stands was first developed as a hotel and a cottage around 1885. It's only 65 feet from mean high tide, but set high enough that waves haven't damaged it through more than a century of hurricanes and winter storms. Bob Blackwood's property, located on a cliffside high off the ocean on Cloyster Street in South Portland, is in a newly designated floodplain zone.

The Federal Emergency Management Agency isn't impressed by that history. The agency, in preparing new flood plain maps for five Maine counties, has placed Blackwood's home in a high-risk zone. During a 100-year storm, it's assumed, 3-foot waves could crash into the building and cause major damage.

…Determining flood zones isn't an exact science. The settlement reached last month between FEMA and the city of Portland over mapping around Portland Harbor shows how the agency's highly technical calculations are open to debate. Similar disputes are happening across the country, and they're shaping up to be especially heated on the Maine coast. In Casco Bay, the dynamic seascape of islands, peninsulas and ledges is not well-suited to FEMA's baseline wind and wave measurements.

…The maps are the basis for federal flood insurance, which is required on mortgages for property in flood zones. With millions of dollars and future development at stake, the outcome of the early appeals may be instructive, as more flood plain maps are updated across Maine in the years ahead.

…But as the issue heats up, one key part of the debate is missing -- the impact of climate change and sea level. …That's bound to put more property at risk of flooding. But because no one can agree on the rate of sea level rise, there are no legally accepted numbers that engineers can plug into computer models for mapping flood plains….

Maine Coast Near Bar Harbor, by Hermann Ottomar Herzog