Walnut Gulch Experimental Watershed
The Walnut Gulch Experimental Watershed, surrounding Tombstone, Arizona, was established in the 1950s to study floods and the impact of soil and water conservation projects on runoff. Researchers continue to study the effects of land use changes on hydrological processes.
Rain gauges and runoff-measuring flumes collect data in the 37,000-acre watershed. In fact, over half-a-century of data has been collected so far. Researchers from the University of Arizona and the U.S.D.A. Agricultural Research Service analyze the information to characterize precipitation in thunderstorms and to study and model subsequent flood wave movement, transmission losses, and water yield from rangeland watersheds.
Historical records indicate that most of the Walnut Gulch Experimental Watershed was grassland a century ago, but shrubs now dominate the lower two-thirds of the watershed. Major vegetation includes the grass species of black grama, blue grama, side-oats grama, bush muhly and Lehmann love grass, and shrub species of creosote bush, white-thorn, tarbush, snakeweed, and burro-weed.