The Heihe Watershed Allied Telemetry Experimental Research (WATER) (HiWATER) experiment is currently being conducted in the Heihe River Basin in China. Its predecessor experiment, the WATER project, was conducted in the same river basin from 2007 to 2010. As an interdisciplinary, intensive, coordinated, and multiscale experiment, WATER produced data that ranged from remote sensing observations to field campaign measurements. These data, which comprise a total of 2.1 TB contained in 255 data sets, were released on the WATER data Web site in July 2010. This letter provides an overview of the WATER data repository, the major data sets, and some data examples. The WATER Information System (WIS), which enables the user community to explore and to order the data in a simple manner, was designed. The data acquisition records indicate that the WATER data sets have received extensive attention and demonstrate that WIS works effectively. Numerous scientific applications have been achieved with the aid of WATER data collection, and some of these applications have revealed that the availability of complete high-quality data produced from a large-scale experiment can provide substantial support to studies of ecohydrological processes and remote sensing and also aid the development of watershed sciences. HiWATER will use the data information system developed during WATER to make it freely available to international scientific communities.