Technical Abstract: An historic experimental watershed in the Texas Blackland Prairie near the town of Riesel, Texas, has provided valuable information to the water resource community for more than 70 years, making it one of the longest continuously monitored hydrologic research sites in the country. The Riesel Watershed, as it is commonly called, is one of many experimental watersheds operated by the Agricultural Research Service (ARS) - the chief in-house scientific research agency of the U.S. Department of Agriculture. Of the three original watersheds established by USDA in the late 1930’s, the Riesel Watershed and the North Appalachian Experimental Watershed near Coshocton, Ohio, are still operating. The contemporary value of the ARS watersheds in providing science to conserve, protect, and allocate our Nation's precious water resources is especially urgent today, as most scientists and engineers expect increased water supply shortage, flood occurrence, and water quality degradation to adversely affect future generations. Cost-effective solutions to these extremely complex problems can only be developed with dedicated science, innovative engineering, real-world data, wise policy, and effective education; all of which rely on long-term watershed-based research and monitoring.