NYC Institutes First of its Kind Modeling System for Reservoir Management

Operations Support Tool Uses Real-Time Data and Advanced Forecasts to Guide Reservoir Operations Review of Data Leads to New Standard for “Normal” Storage in Reservoir System

OST functionalities support a wide range of DEP uses, including short term operational projections, outage planning and emergency management, operating rule development, and water supply planning.

(NEW YORK, NY – January 22, 2014) – Department of Environmental Protection (DEP) Commissioner Carter Strickland today announced that an innovative reservoir management system, known as the Operations Support Tool (OST), has been integrated into the daily operations of New York City’s reservoir system. The OST predicts future storage in the City’s reservoir system by accounting for dozens of variables such as weather forecasts, current demand for water, and myriad changes to the operation of the water supply. The $8 million modeling system will allow DEP to divert or release water from its reservoirs at the most opportune times to help ensure the highest quality drinking water is delivered to more than 9 million New Yorkers, and to benefit downstream communities by enhancing the health of local streams while reducing the risk of flooding.

“New York City is breaking new ground with the development of the Operations Support Tool, which is the first modeling system of its kind for any water utility in the country,” Strickland said. “By integrating the best available data into our operational decisions, the OST will help to ensure that we can continue to supply nearly half the state’s population with the highest-quality drinking water while respecting the needs and desires of those that live in and around the watersheds.”

The OST incorporates dozens of variables – including real-time data – into the decision making process. Information used by the management system includes:

Reservoir operating rules: The capacities of the City’s aqueducts and reservoirs, as well as operating rules related to stream releases and water supply diversions, serve as a foundation for OST. These rules include the Flexible Flow Management Plan for Delaware System reservoirs, the Interim Release Protocol for Ashokan Reservoir, required releases from Croton System reservoirs, and more. This ensures that OST does not yield options that are outside the scope of existing regulations or the water supply system’s capacity.

Weather and environmental data: OST uses real-time data from a number of sources, including stream gauges, devices that measure the water content of snowpack throughout the watersheds, and rain gauges, as well as forecasts from the National Weather Service. These data help DEP forecast the amount of water expected to enter the reservoir system, also known as runoff or “inflow,” over a period of time.

In-city and upstate demand: The modeling system also incorporates the demand for drinking water in the city and among the more than 70 communities upstate that use water from the city’s water supply system. Along with required releases to rivers, creeks, and streams, demand accounts for “outflow” from the system.

Operational changes: OST also allows DEP to test different operational decisions to project how each would affect the water supply system in the months ahead. For instance, if DEP chose to divert 300 million gallons a day from one of its reservoir systems instead of 500 million gallons, OST can project how that decision and dozens of others will affect system storage, water quality, required releases, and more.

This advanced modeling allows DEP to test different operational changes in a virtual setting – and understand their outcomes – so that daily decisions are made with the best available information. OST also takes into account how ongoing construction projects might affect the water supply, and it will help DEP make operational changes ahead of big storms to limit turbidity, and the effect of wind and other factors.

DEP began developing OST with consultant Hazen and Sawyer in 2009 and portions of the system were phased into DEP’s daily water supply operations as they were completed. The OST will continue to be updated in the future to reflect changes to regulations, infrastructure, and other factors affecting water supply operations.

For more information, visit the DEP website.

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