About 35,000 homes and businesses inside and outside New York City are being added to flood zones under new preliminary federal maps. They're expected to affect flood insurance rates and zoning rules.
The revised maps released by FEMA on Monday are preliminary, but they will likely become a basis for changes to building laws and insurance requirements in coming years.
They represent one of the first concrete signals of how officials will carry out vows to rebuild smarter after Sandy and what that will mean for property owners. While a roughly two-year review is expected before new maps become official, New York City is planning short-term steps to encourage owners of Sandy-damaged properties to rebuild in the meantime.
"What we're trying to do is provide the means, immediately, for people who want to move forward now to be able to do so," Deputy Mayor Cas Holloway said.
And for everyone else, the information provides "time to think and plan what kind of changes they would want to make," he said.
The current flood maps for the city date to the 1980s. A revision was already planned before Sandy, but the Oct. 29 storm "created an urgency for us to do it," said Michael Byrne, who's overseeing FEMA's Sandy response in New York state. The storm devastated sections of Staten Island, Brooklyn and Queens, swamped lower Manhattan and flooded some areas that had been expected to stay dry.
The maps released Monday address Brooklyn, Staten Island, Queens and suburban Westchester County. Maps for the rest of the city are expected next month. Long Island's maps were updated in 2009.
The key zones on the maps indicate how far above sea level a building's ground floor would have to be to withstand flooding from a storm so strong it's given a 1 percent chance of happening in any given year.
Those zones cover 35,000 more homes and businesses in the new maps, sweeping up more of the coastline and reaching farther inland. In Brooklyn, for example, the Seagate, Brighton Beach and Manhattan Beach neighborhoods are now included alongside already designated areas like Coney Island.
The implications vary by property, depending on topography and the present height of a building's ground floor.
Some "might already be safe ... but there are going to be plenty of cases where people have to bring their homes up higher," said Jon Janowicz, a FEMA official working on the mapping project.
For many property owners, the difference between the old and new flood lines is 3 to 6 feet. That means new construction eventually will probably have to be set 3 to 6 feet higher than what is currently required, since the city is expected to revise building laws to reflect the new zones.
That's not likely to happen for a couple of years, but city officials are working on a plan to allow and encourage Sandy-damaged property to be rebuilt at the new level, Holloway said.
The costs aren't immediately clear and likely will vary depending on the type of building and other factors. Officials said they were working to determine what government help might be available.
Some new projects are already being revised in anticipation of the new maps. Developers of a massive Ferris wheel, outlet mall and hotel on Staten Island, for instance, began planning after Sandy to move the project up a few feet.
The new maps may have expensive effects even for properties that weren't inundated by Sandy.
An expanded flood zone means more owners may have to buy flood insurance; it's generally required for properties with federally backed mortgages.
And those who already have flood insurance could pay substantially more for it if their properties sit below the new flood levels. Under changes to the federal flood insurance program last year, owners of a $250,000 home with a ground floor three feet below the flood level would pay $9,500 a year, compared with $1,410 for a house at the flood line, according to FEMA, which administers the flood program. The increases are to be phased in over five years for existing buildings, after new maps are formally adopted.