The Federal Emergency Management Agency’s new preliminary flood insurance rate maps for Suffolk County show far fewer houses in the floodplain than when the last maps were completed in 1983—but Southampton Town’s stormwater manager is concerned that they do not take all of the potential flood areas into account.
FEMA has been overhauling old flood maps throughout the country using new Light Detection and Ranging, or LIDAR, technology that is purported to be far more accurate than the methods used to create the existing maps.
“FEMA paid almost $2 million for a new digital elevation model and new hydraulic coastal analysis,” said Paul Weberg, a senior engineer at FEMA’s New York offices, who was answering questions from concerned residents at a special information session on Thursday night, November 13. The session was held by FEMA and the New York State Department of Environmental Conservation at the Southampton Cultural Center.
According to the new maps, the number of houses in the floodplain in Southampton Town will likely decrease from 3,579 to 3,104. In neighboring East Hampton, the number will decrease from 1,632 to 1,512.
The only areas that show an increase are the villages of East Hampton and Sagaponack. In East Hampton, 60 houses had formerly been in the floodplain; if the new maps are adopted as currently sketched, that number will increase to 146 houses. In Sagaponack, only 46 houses had been in the floodplain, but the new maps show 119 houses in the area of high risk.
Residents who find that their houses are now in the flood zone will have until February 11 to appeal their status by filing a letter with FEMA and the DEC, with a surveyor’s map indicating that they should no longer be in the zone they are in.
The differing levels of flood zones can also cause confusion for homeowners who are looking at the maps for the first time. Though homeowners in the floodplains are required to have flood insurance if they are carrying a mortgage, the type of zone also determines what kind of foundation their houses are permitted to have. For example, in the A zone, homeowners can have concrete foundations, while in the VE zone, where their house will likely be subject to pounding waves in a severe storm, the house can be built only on wood pilings.
“These maps are only showing 1 percent of the true flood zone,” cautioned Walter Bundy, Southampton Town’s stormwater manager. “It doesn’t even look like the storm surge zone.”
The maps are designed primarily to point out which homeowners must have flood insurance in order to fulfill the obligations of a mortgage and which will pay more for flood insurance due to higher risk. They don’t include all of the areas that might flood in a severe storm, which, depending on tides, winds and rainfall, could easily occur far outside the map’s projected flood area.
As Mr. Weberg explained it, the maps indicate the damage that could be done by a 100-year storm, which is not a storm that occurs once every 100 years but a storm that has a 1-percent chance of occurring each and every year. Such storms have become more frequent in recent years, which most scientists attribute to climate change.
Mr. Bundy said that Southampton Town has the option of adding a new zone to the flood rate maps that would account for houses that would be damaged by waves that aren’t as strong as the waves required to put homeowners in the VE zone. Doing so, he said, would make the current flood maps moot and prolong the process of adopting the maps, which FEMA already anticipates won’t happen until 2010.
FEMA representatives, however, said they have no plans to change the maps. “Not that I know of,” said Mr. Weberg of the notion of adding a zone. “Right now it’s only advisory.”
Mr. Bundy said that the town will likely adopt the additional zone in the interest of regulating more strict building codes in areas that are prone to flooding, though the zone will not have an impact on flood insurance rates.
Mr. Bundy also said that there are several problems with FEMA’s maps that the town still needs to address before it adopts its version of the maps. He estimated that final maps will not be available for the town to adopt until late 2009, after which they will be adopted by the federal government.
“There are a lot of issues with the technology used,” said Mr. Bundy.
Among those issues, he said, was the inability of FEMA’s technology to distinguish bridges from solid shoreline-hardening structures. He said that such a problem would make it impossible for the map makers to measure the storm surge water that makes its way under a bridge and onto private properties.
Mr. Bundy added that FEMA’s interactive website, suffolknyfloodmaps.com, is severely flawed. He said that 17 percent of the addresses in the town couldn’t be found using the website.
He added that the town is in the process of loading FEMA’s information into its Geographic Information System and will allow residents to access their information using town GIS computers, which he believes will provide more accurate data.