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Water Supply

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Water Supply

This page contains data, reports and information related to water supply forecasts, reservoirs, and the Surface Water Supply Index (SWSI).  This information is provided to assist in forecasting the water supply for the western United States.

Snow Survey and Water Supply Forecasting

The purpose of the program is to provide western states and Alaska with information on future water supplies. NRCS field staff collect and analyze data on depth and water equivalent of the snowpack at more than 1,200 mountain sites and estimate annual water availability, spring runoff, and summer streamflows. Individuals, organizations, and state and Federal agencies use these forecasts for decisions relating to agricultural production, fish and wildlife management, municipal and industrial water supply, urban development, flood control, recreation power generation, and water quality management. The National Weather Service includes the forecasts in their river forecasting function.

The objectives of the program are to:

  • Provide water users with accurate forecasts of surface water supply within the first 5 working days of each month, Jan.-June.
  • Efficiently obtain, manage, and disseminate high quality information on snow, water, climate, and hydrologic conditions.
  • Develop and apply technology necessary to meet changing needs of water users.

Water & Climate Center Website

Snow scene in Flagstaff, Arizona
The National Water & Climate Center website delivers snow and water data that is updated on a daily, even hourly basis. The Center website will be moved to a new web content management system used by NRCS in 2012. In the meantime, please visit the current National Water & Climate Center website.