The National Water Model forecasting tool simulates how water moves throughout the nation's rivers and streams generating hourly forecasts for the entire river network. The model also improves NOAA's ability to meet the needs of its stakeholders -- such as emergency managers, reservoir operators, first responders, recreationists, farmers, barge operators, and ecosystem and floodplain managers -- with more accurate, detailed, frequent and expanded water information. Initially, the model will benefit flash flood forecasts in headwater areas and provide water forecast information for many areas that currently aren't covered. As the model evolves, it will provide "zoomed-in," street-level forecasts and inundation maps to improve flood warnings, and will expand to include water quality forecasts.