HISTORY

After a severe storm caused transportation disruptions and structural damage throughout New York City on August 8, 2007, Mayor Bloomberg launched the Flood Mitigation Task Force to coordinate and enhance the City’s response to flooding and leverage the capabilities of each agency to address storm-water management. One of the goals of the task force was to develop a comprehensive citywide plan to improve residents’  flood preparedness (PDF, 1.59 MB) and ability to recover from flash floods.
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HAZARD DEFINITION: FLASH FLOOD

A flash flood is a rapid rise of water along a stream or in a low-lying urban area. Most flash flooding is caused by slow-moving thunderstorms, thunderstorms repeatedly moving over the same area, or heavy rain from hurricanes and tropical storms. Densely populated urban areas are at particular risk for flash floods because most surfaces are paved and impermeable. Very little rainfall in New York City is absorbed by the ground. Instead, most of it flows into street-level catch basins and then into sewers. Periods of intense rain can overwhelm storm sewers and cause flash floods. Clogged or obstructed catch basins can lead to flooded street corners, underpasses, underground parking garages, and basements.

OVERVIEW OF THE PLAN

The Flash Flood Emergency Plan describes a coordinated response to flash floods in New York City. The plan contains detailed procedures to minimize a flood’s effects on New Yorkers and their property. 

PLAN OBJECTIVES:

• Reinforcing weather monitoring protocols among City agencies to increase situational awareness
• Targeting stormwater infrastructure for maintenance in recurring flood locations
• Monitoring flood-prone locations during intense rain to target maintenance, emergency response, and recovery
• Providing recovery assistance to affected populations following a flash flood