Flood prevention in Manhattan

This case study outlines steps taken in Manhattan to prevent flood damage, including use of AquaFence stuctures.

AquaFence temporary flood barrier being set up around New York Plaza
AquaFence temporary flood barrier being set up around New York Plaza

Flooding is one of the most complex property risks facing property owners and insurers alike.

Ongoing analysis by the FM Approvals® parent company, FM Global, shows that a property located within a published flood zone is five to seven times more likely to suffer a flood loss than to suffer an equivalent loss due to fire or explosion. In addition, the average flood loss is about 1.5 times as great as the average fire loss.

A new study published in the journal Nature Climate Change predicts that average annual flood damage losses in Europe will increase to €23 billion by 2050, compared to the €4.9 billion seen between 2000 and 2012.

Many companies are installing flood abatement systems and equipment to proactively guard against future flood losses, particularly following Superstorm Sandy, which devastated large portions of the United States Northeastern Seaboard in October 2012. Sandy caused an estimated US$70 billion in total losses and US$35 billion in insured losses.

Norwegian flood protection comes to the Big Apple

A year before Sandy made its mark as the second costliest hurricane in U.S. history, Hurricane Irene was considered a dud by many Manhattan, N.Y., USA residents, despite the devastation it caused to many inland areas. "Over-hyped" was the consensus of many who weathered the media storm that preceded Irene.

For this reason, perhaps, many residents of Manhattan's low-lying 'Zone A' defied mandatory evacuation orders a day prior to Sandy's arrival on October 29, 2012. "Hurricane Irene was a tropical storm by the time it reached us," notes Nehad Moughrabi, the resident property manager of New York Plaza at Two Water Street, a 19-story mixed residential and retail tower owned by Pan Am Equities and located one block from Battery Park on the lower tip of Manhattan. "There were wind gusts and lots of rain. We figured Sandy wouldn't be much worse than Irene."

About 15 percent of the tower's residents followed mandatory evacuation orders for 'Zone A' residents. Although many tower residents chose to ignore the warnings, Nehad and his team worked hard to prepare. They created sandbag barriers around the main entrances and service doors. Despite these and many other preparations, the ground floor and cellar of New York Plaza at Two Water Street were inundated the evening Sandy struck.

The Pan Am Equities team used a rented generator and was able to pump out the cellar water within 48 hours. Electrical switch gear equipment was power washed to clean the salty water, and blowers and dehumidifiers were used to dry equipment prior to restoring power. Lobby finishes had to be replaced, as well as electrical switch gear, boilers, pumps and controls, air conditioning, fire alarm system, security cameras and door access systems, and the New York Health and Racquet Club (NYHRC) space in the cellar. Damages amounted to approximately US$15 million.

Thanks to the hard work of Nehad and his crew, the residential portion of the tower was able to restore all building operations and reopen just 10 days after Sandy. The NYHRC, a tenant occupying the lower floors of the tower, was able to restore the cellar portion partially on May 15, 2013. However, the NYHRC facility was not fully restored until January 2014.

Taking protective action

Like many property owners in lower Manhattan and other low-lying areas of the state, one of the first steps taken by Pan Am Equities following recovery from Sandy was to find and install flood protection systems. This was not only prudent, but viewed favorably by insurers reeling from massive Sandy losses.

When the Pan Am Equities management team looked at available perimeter barriers for its New York Plaza at Two Water Street location, it quickly became clear that the AquaFence system was the right choice. "We liked the effectiveness, ease of installation, minimal set-up time, compact storage and reasonable cost," says Pan Am Equities President and Chief Executive Officer Scott Solomon. "We believe our acquisition of AquaFence may have actually made us insurable with respect to a flood casualty at this location."

Pan Am Equities purchased approximately 122 m (400 ft.) of AquaFence, enough to surround the building with a continuous temporary barrier. The barrier is stored at another nearby Pan Am Equities owned building and can be readily moved by truck to New York Plaza at Two Water Street.

"Pan Am Equities was somewhat concerned because they would be the first company in New York City to purchase AquaFence," notes Adam Goldberg, director of New York operations for AquaFence. "They were aware of our ongoing test program with FM Approvals and the Army Corps, which really helped."

How to avoid flood losses

Facilities at risk for flooding must prepare well in advance in order to keep water out of critical buildings and limit resulting damage if floodwater enters a structure. FM Global Property Loss Prevention Data Sheet 1-40, Flood, provides recommendations for the prevention and mitigation of losses due to flooding.

FM Global loss history studies show that well-prepared organizations—including those with a tested FERP—have significantly less damage and resume operations sooner than those unprepared. Guidance in preparing a FERP is included in FM Global Property Loss Prevention Data Sheet 10-2, Emergency Response.

If the relocation of critical equipment is not possible, then permanent protection should be considered. Other preparations include backflow preventers and sump pumps for drains and sewers; relocation of elevations greater than the flood level of high value stock and processing equipment; and permanent or temporary barriers to protect buildings and building openings against flood waters.

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