Agenda - Planning Commission - 01/09/2014

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High and Dry n the Waterfront By James C. Schwab, AICP Just north of New York City, in Rockland County, New York, on the western side of the Hudson River, sits the village of Piermont on a little more than one square mile of land, with about 2,50o people. Within that village lives Klaus Jacob, a seismologist at Columbia University's Lamont -Doherty Earth Observatory, who helped generate remarkably accurate estimates of the likely loss from an event like Hurricane Sandy. What is equally remarkable is what happened to his home in Piermont. Taking a hint from Hurricane Irene in 2011, Jacob, who had already raised his house in 2003, wanted to avert damage by raising it higher above the base flood elevation established by the Federal Emergency Management Agency (FEMA) before Sandy hit. He soon learned that the town had a 22-foot height limit in its zoning regulations. His eight -foot -high top floor woul&exceed that limit if he elevated the house, and he chose not to give up the attic. Instead, he and his wife did what they could to elevate their kitchen ap- pliances, including the stove, within the exist- ing structure. That saved some of their property from the flooding from Sandy, but the existing zoning kept them from saving more. For a sci- entist who had worked with New York planners to estimate correctly the impact of Sandy, this outcome was, to say the least, a bit ironic. In a YouTube video produced after the storm by the university's Earth Institute, Jacob notes that Sandy produced flooding one to two feet above the soo-year floodplain, "affecting a lot more people than those that normally get flood insurance, including myself."The result in Piermont, he says, was a "microcosm of what happened in New York City." WHERE TO DRAW THE LINE Questions such as those that faced Jacob become more likely after almost every natural disaster that involves flooding, whether from hurricane storm surges or from torrential down- pours overloading rivers and streams. Those events trigger a process within FEMA's National Flood Insurance Program (NFIP) to reassess existing flood maps based on new flood data, resulting in Advisory Base Flood Elevations (ABFEs) that establish new benchmarks for how high the soo-year flood will rise in specific locations. That base flood elevation is actually the level at which there is deemed a one per- cent annual chance of a flood occurring. It is a product of engineering calculations taking into account the historic experience with flooding in a community at the time the map is produced. The problem is that such maps are not static. They are influenced overtime by the amount of development and impervious surface allowed into the floodplain and even the overall water- shed. In the case of New York City, the maps that existed prior to Sandy dated from 1983. The city was well aware that they were out- dated and was concerned about their accuracy before the storm. FEMA released the new ABFEs for New York and New Jersey in February 2013. There are two primary consequences of these maps. The first is a change in flood insurance rates for properties previously located beyond the base flood elevation that now find themselves within the soo-year floodplain. In some cases, that may trigger requirements for flood insur- ance that did not previously apply to those properties; in others, it may simply mean that flood insurance becomes more expensive. The second consequence is that NFIP regulations require some form of mitigation for properties in the floodplain that are substantially dam- aged; that is, those that have suffered damage exceeding 5o percent of market value. Mitiga- tion can take a number of forms: wet or dry floodproofing, elevation, and buyouts are the most common. As a result of ABFEs including additional properties within the newly mapped floodplain, the owners are unable to rebuild without taking some appropriate action to reduce risk. The scope of damage from Sandy gives some indication of the size of the rebuilding challenges that face these communities. Ac- cording to the National Hurricane Center, Sandy damaged or destroyed nearly 650,00o homes in an arc ranging from Rhode Island to Mary- land. It also killed 147 people in New York, New Jersey, and Connecticut. In New York City, 218,00o residents live within currently mapped floodplains. The city has 52o miles of waterfront, much of it devoted to industrial and commercial uses; it is by far the largest shoreline of any city in the U.S. Ap- proximately 90,00o buildings in New York City were in areas flooded by Hurricane Sandy, and 84 percent of those were built before FEMA produced its first flood insurance rate maps (FIRMs) for the city in 1983. New York thus has a great deal of property that is not compliant with current standards, much of which faces significant costs to upgrade to current codes. Moreover, in an urban area as dense as New York, relocating structures is often simply not an option. Other strategies are needed. The city's study of its urban design options, De- signing for Flood Risk, notes that 98 percent ZONINGPRACTICE ai.i3 AMERICAN PLANNING ASSOCIATION I page 2