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FACT SHEET - Passaic River Flood Warning System

Flood Warning System Emergency Operations

U.S. Army Corps of Engineers, New York District
Published Nov. 20, 2023

DESCRIPTION: The 935-square-mile area covered by the Passaic River Flood Warning System contains 132 communities within the States of New Jersey’s and New York’s counties of Bergen, Essex, Hudson, Morris, Passaic, Sussex, Somerset, Union, and Rockland.  This area contains a population of approximately 2.5 million people and over 20,000 homes and businesses.  The Passaic River Flood Warning System consists of fifty-six (56) stream level gages and precipitation gages. 

The gages transmit observational data via individual Data Collection Platforms (DCPs) to the National Environmental Satellite, Data, and Information Service’s (NESDIS) Geostationary Operational Environmental Satellite (GOES) system.  The DCPs at the stations transmit near real-time stage, discharge, and/or precipitation data from these sites hourly via the GOES satellite. The data are displayed on the USGS National Water Information System (NWIS) Website (waterdata.usgs.gov/nj/nwis/rt), to be accessed by the general public. Historical daily-mean flow, peak flows, and field measurements of streamflow are available from the USGS NWIS database on the web at waterdata.usgs.gov/nj/nwis/sw. All stream and reservoir data will be published to the USGS NWISWeb.

The observations from this system form the basis for the river forecasts provided by the NWS Mid-Atlantic River Forecast Center (MARFC). The NWS Weather Forecast Offices in Mount Holly, New Jersey and Upton, New York use these observations and river forecasts in their watch and warning responsibilities for flood and flash flood events. The NWS provides the observed and forecasted streamflow data as well as watch warning and advisory information on the Advanced Hydrologic Prediction Service webpage: http://water.weather.gov/ahps.

In addition, the real-time data can be obtained from the US Geological Survey’s WaterAlert System, which is a subscription notification service that sends subscribers real-time data via email or text:   http://water.usgs.gov/wateralert/index.html. Daily and hourly updates are sent when the current conditions at the gage meet or surpass a threshold of concern that is set by the user. This system will notify users when the stage, discharge, or water-quality parameter at a USGS gage of interest reaches or exceeds a preset threshold.

AUTHORIZATION: Section 101(a)(18) of the Water Resources Development Act of 1990 (PL 101-640), as amended by Section 102(p)(1) Water Resources Development Act of 1992 (PL 102-580).

STATUS: Normal operations and maintenance efforts continue within a partnership between the US Army Corps of Engineers and the US Geological Survey.




Sean O’Donnell, P.E.
Emergency Manager/ Chief, Readiness Unit
P:  (917) 790-8500
Email: Sean.B.Odonnell@usace.army.mil

U.S. Army Corps of Engineers, New York District
26 Federal Plaza
New York, New York 10278

DISTRICTS:  NJ-5, NJ-7, NJ-8, NJ-9, NJ-10, NJ-11