Wednesday, December 4, 2013
By Tux Turkel email@example.com
SOUTH PORTLAND - 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.
Jill Brady/Staff Photographer
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.
Using FEMA's calculations, 17 or so homes in Blackwood's neighborhood are in the high-risk zone, including a house across the street that's higher and farther from the water. The designation could lead to more costly flood insurance, and prevent property owners from building or rebuilding, so Blackwood is upset.
"People have been living in these places for 125 years or so, and we haven't had the storm they're talking about yet," he said.
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 agency, which has spent $3.2 million so far in southern Maine, says it doesn't have the budget to do a more detailed analysis.
Two dozen coastal communities in York and Cumberland counties are having flood plains remapped. Several have followed Portland's lead and hired a consultant to challenge the changes.
The challenges come as FEMA prepares to resume an appeals period this summer. Property owners in or near the updated hazard zones are being advised to pay attention.
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.
The federal government began a program to map flood plains in 1969. In 2003, Congress authorized updating the maps and putting them into a digital format. That process is under way in Maine, which still lacks detailed coastal elevation data east of Brunswick. Federal stimulus money will close that gap this fall, paying for aircraft with laser technology to finish the job.
But topography and water depths are only part of the picture. On the coast, FEMA also collects data for wind speeds and waves, calculating how high they could get at the peak of a storm that, statistically, happens only once in a century.
In Portland Harbor, the initial calculations led FEMA last year to put much of the waterfront in a high-hazard zone. That would have stopped construction on Portland's piers, and rebuilding of structures more than half destroyed by storms.
To challenge the designation, Portland hired Robert Gerber, an engineer for Sebago Technics in Westbrook, who specializes in computer modeling of environmental systems.
Gerber used sophisticated modeling, and data from the Portland International Jetport and a weather buoy, to recalculate the effect of waves and wind on Portland Harbor. He determined that the peak, sustained wind speed in a 100-year storm would be 52 mph, not 71 mph, as FEMA had assumed. That lowered the projected wave height from 5 feet to less than 3 feet.
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