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January 21, 2010


Anne Canty/Mercedes Padilla/Angel Roman (718) 595-6600

DEP Expands Initiative To Better Measure Snowpack, Mitigate Flooding

Electronic ‘Snow Pillows’ Provide Real-Time Data on Amount of Water in Snowpack

The New York City Department of Environmental Protection (DEP) today announced it is expanding the testing of electronic "snow pillows" first installed in 2008.  The snow pillow is a device that measures the amount of water in snowpack for a watershed area. Snowpack is a crucial indicator of overall water supply because melting snow drains into reservoirs. DEP, the first agency in the country to use this state-of-the-art technology, installed five new snow pillows over the last month on the Catskill/Delaware watersheds. The total cost of this project is $50,000.

"This is a prime example of new technology that will improve our operations by providing real-time information concerning the water content of the snowpack," said Environmental Protection Commissioner Cas Holloway.  "Data from the snow pillows will supplement the detailed information we already collect in the Watershed, such as stream flow, weather conditions, and reservoirs levels.  Taken together, this information increases our operational responsiveness and our ability to protect water quality by helping us better anticipate the likelihood of turbidity events caused by large snow melts."

The electronic snow pillow was initially developed by the U.S. Army Corps of Engineers in Alaska.  Based on knowledge gleaned from the pillows installed by DEP in 2008, DEP developed a simpler design now being used at locations within the Cannonsville, Pepacton, and Neversink reservoir watersheds. One of the original 2008 pillows is used at a location within the Schoharie Reservoir watershed. Locations for the pillows were chosen in partnership with the National Weather Service, which is using data from several sites to improve a snowmelt and flash flood forecasting model they are developing.

The new snow pillow design is an aluminum triangle with highly accurate scales that take measurements every 60 seconds, sending the information to a DEP facility every hour via radio transmission. While DEP staff will continue to perform field checks throughout the watershed, the snow pillows provide continuous, real-time data on snowpack water content.

Under the Flexible Flow Management Plan, which is intended to provide a more adaptive means for managing the Cannonsville, Pepacton, and Neversink reservoirs, DEP includes half of the   water content in the snowpack in the total storage for its Delaware reservoirs. Accounting for this snowpack water allows DEP to enhance the flood attenuation already provided by the reservoirs.

DEP manages the City’s water supply, providing more than 1 billion gallons of water each day to more than 9 million residents, including 8 million in New York City, and residents of Ulster, Orange, Putnam and Westchester counties. Approximately 1,000 DEP employees live and work in the watershed communities as scientists, engineers, surveyors, and administrative professionals, and perform other critical responsibilities. DEP has invested over $1.5 billion in watershed protection programs.

More Information

NYC Department of Environmental Protection
Public Affairs

59-17 Junction Boulevard
19th Floor
Flushing, NY 11373

(718) 595-6600