Agricultural Water Resources Decision Support System

The Bureau of Reclamation (Reclamation) is the largest wholesale supplier of water in the United States and serves more than 31 million people in the 17 contiguous Western States, providing more than 9.3 trillion gallons of water each year. Accurate, timely hydrometeorological information is essential for efficient water management. The National Weather Service (NWS), in partnership with other agencies, has installed a network of around 140 WSR-88D or NEXt generation weather RADar (NEXRAD) systems throughout the contiguous 48 States. Great potential exists for agencies such as Reclamation to apply enhanced NEXRAD precipitation products for improving the efficiency of water resource operations.

One example of Reclamation's efforts to make operational use of NEXRAD precipitation estimates is the development of the Agricultural WAter Resources Decision Support (AWARDS) system. The AWARDS system is based on modern remote sensing, communication, computer, and Internet technologies. The AWARDS system is an automated information system that has been designed to assist water managers and users by providing easy access to rainfall and daily crop water use estimates. The purpose of the AWARDS system is to improve the efficiency of water management and irrigation scheduling by proving guidance on when and where to deliver water, and how much to apply.

AWARDS systems that have been implemented east of the Continental Divide use the NEXRAD Stage III hourly product produced by the NWS River Forecast Centers (RFC). Every hour, the Stage III data files are automatically collected into the AWARDS computer via file transfer protocol (ftp) from the RFC. Automated weather stations in AWARDS system areas transmit surface weather data via radio signal, phone, or satellite to local computer systems. The data are then automatically collected from the local computer systems, via ftp, into the AWARDS computer. NWS 24-hour Quantitative Precipitation Forecasts (QPF) are automatically collected from the RFCs. Finally, Eta model gridded parameters are automatically collected from the National Centers for Environmental Prediction (NCEP) and used to make 24-hour ET forecasts over the project areas.

Various Geographic Information System (GIS) data resources are used, such as watershed, hydrologic, political boundary, irrigation district conveyance system, and other features, for developing the base maps for the AWARDS system. These data are transferred to longitude-latitude coordinates for input to a graphics program available from the National Center for Atmospheric Research, called NCAR Graphics. The Hydrologic Rainfall Analysis Project's (HRAP) 4 km x 4 km resolution grid cells are plotted and overlaid with the NEXRAD precipitation estimates and weather station rain gage measurements. Once the day's data are accumulated, computer programs produce 24-hour summaries and make them available on the Internet site images. Lastly, the Penman based evapotranspiration (ET) crop water use estimates, weather data, QPF, and ET forecasts are integrated into the images via pop-up charts. Reservoir operators, water managers, and on-farm water users access the AWARDS system products via the Internet to make their operational decisions.