WRF-Hydro and the National Water Model


Over the past four years, a team of RAL scientists and engineers have developed and transitioned the community WRF-Hydro modeling system into the National Water Model (NWM), the first operational, high-resolution, physics-based hydrologic prediction model ever implemented across the continental U.S.  Developed in close collaboration with the National Weather Service (NWS) Office of Water Prediction, the USGS, and a number of university partners, the RAL team delivered the first version of the model in only one year (two years ahead of schedule) on a modest budget. The model is now being used, to solve a complex problem—tracking water flow across the country to aid local communities and emergency managers in responding to water-related threats.  It is also providing consistent, reliable, high-resolution data to decision makers across the country, helping them address increasingly complex societal issues related to flooding, drought, water availability and water quality. In addition to providing significant benefit to the operational community, the NWM is proving to be a valuable tool in the conduct of research and as a mechanism for moving research to operations.  The NWM provides an important bridge between the numerical weather prediction community and the terrestrial hydrology community. As an open source, open platform model, the NWM and WRF-Hydro will continue to evolve to meet the nation’s complex needs for water resource planning and management information while also providing a seamless pathway for academic researchers to innovate new improvements in water prediction. 

Notable Recognition - National

In September 2017 the Department of Commerce recognized the development and implementation of the National Water Model with a Gold Medal for Scientific/Engineering Achievement; this is the highest award given by the agency. The award noted that “the NWM is the first high-resolution CONUS-wide water forecast model executed in the operational NOAA supercomputing environment.  It provides first-of-its-kind water resource guidance to NWS River Forecast Centers and other end users…” The NOAA/NCAR development team was specifically praised for demonstrating “exceptional dedication, hard work, expertise, and creativity.”  The WRF-Hydro modeling system, which was developed at NCAR, has been successfully transitioned into the nation’s new state-of-the-art operational water prediction system through this exemplary NOAA/NCAR partnership.

Local Recognition

In December of 2017, the NCAR WRF-Hydro/NWM development team within the Research Applications Laboratory was awarded an Outstanding Accomplishment for Scientific and Technical Advancement for the development and implementation the National Water Model, the first operational, high-resolution, hydrologic prediction model to be implemented across the continental U.S.

Accomplishments & Goals:

FY2019 National Water Model (NWM) Version 2.1 development lead to many scientific and technical advancements which include but are not limited to the following.

  • Improved representations of meteorological forcings and groundwater fluxes for the NWM implementation for Hawaii.
  • Development and implementation of the NWM for Puerto Rico and the U.S. Virgin Islands making this implementation the first 24/7 analysis and hydrologic forecast service for this region.
  • Expanded and improved hydrologic model parameter estimation, calibration, and regionalization methods increased the skill in NWM analyses and forecasts.
  • Improved treatment of snowpack ablation and melt water dynamics and their interactions with soil runoff generation mechanisms.
  • Implementation of new meteorological forcing data bias corrections to improve the quality of source meteorological data driving NWM forecasts.
  • An expanded capability for ensemble seasonal water supply forecasting in the western U.S. was established to demonstrate and provide quantitative evidence of ensemble seasonal water supply forecasts in the western U.S.
  • Significant expansion of reservoir and water management representation to improve analysis and prediction of mainstream river flows impact by human operations.
  • An updated representation of soil depth to bedrock structure using geomorphically derived soil depth estimates.

FY2020 Goals for NWM Version 3.0 include improvements to the whole WRF-Hydro/NWM Ecosystem and suite of tools as well as focusing on engaging and training our community partners. Listed below are some of the overarching themes.

  • Expand the oCONUS domain and implementing NWM for the Cook Inlet region of southeast Alaska
  • Improve the meteorological forcings in terms of downscaling and rain/snow partitioning and additional bias corrections
  • Improve the land use and land cover representation by using a dynamic land cover specification
  • Improve computational performance
  • Continue code modularization efforts
  • Update groundwater/baseflow representation to better represent low flow conditions and hydrograph recession characteristics.
  • Partner with entities that are working on coupling the NWM to coastal prediction models.
  • Expand options for representing infiltration and surface runoff processes in the NWM.
  • Engage NWS River Forecast Centers with individual hands-on training

Goals of FY20 are to continue to build the WRF-Hydro community by:

  • Expanding the number and type of video recorded webinars on WRF-Hydro and NWM development activities
  • Expanding WRF-Hydro and NWM related news outlets such as Twitter to broaden entrainment of the  global hydrologic community
  • Expanding the online training suite of education modules to reach those users who are unable to attend the hands-on training workshops due to limited seating
  • Expanding the translated model documentation and user guides into Spanish to reach our Latin American and Spanish speaking users around the globe