In Zimbabwe during the 1980s and early 1990s, a sequence of severe droughts caused widespread food shortages and great hardship to rural communities. The droughts exacerbated the problems of environmental degradation in communal lands and highlighted the lack of understanding of the links between the climate, land use and hydrology of dryland regions. The Romwe Catchment Study addresses these issues, and has led to the establishment of the first fully-instrumented research catchment in a communally-managed dryland environment in southern Africa. The key objectives were (a) to improve the understanding of hydrological processes in communal land areas, mostly underlain by crystalline basement aquifers, and (b) to investigate the impacts of variations in climate and changes in land use and management on the hydrology and water resources. In this introductory paper, the physical characteristics of the catchment are described together with the instrumentation to monitor hydrological processes and quantify the catchment water balance.