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Operations Support Tool

Operations Support Tool

Operations Support Tool (OST) is a computerized decision support system that guides the managers that operate the New York City Water Supply System. OST was built through a joint effort of DEP staff, consultants, leading scientists, and the National Weather Service. It is one of the most advanced and complex support tools for water supply operations in the world.

OST is able to:

  1. join together computer models of reservoir operations and water quality,
  2. ingest near-real-time data on streamflow, water quality, reservoir levels, diversions, and releases, and
  3. incorporate cutting-edge ensemble streamflow forecasts from the National Weather Service.

OST then applies all the operating rules and laws governing reservoir operations on the data it collects, and predicts a range of possible future reservoir levels and water quality conditions (as well as their individual probabilities). OST can make projections of reservoir water quantity and quality up to one year in the future. This approach, known as Forecast Informed Reservoir Operations (FIRO), allows managers to make risk-informed decisions regarding water supply operations. Since OST is run frequently, it also allows managers to adjust reservoir operations in response to the latest environmental conditions and evolving weather and streamflow forecasts.

More OST Resources

  • Download our OST Fact Sheet (PDF).
  • A panel of experts from the National Academies of Sciences, Engineering and Medicine strongly endorsed OST for guiding the operation of New York City’s drinking water supply, managing risks such as droughts and turbidity events, and planning for the future effects of climate change. Read the review.

Reservoir Levels

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