This paper describes a spate irrigation system in Makanya village, Tanzania that emerged in response to increased upstream water use. It uses the hydrological, hydraulic and sociological dimensions of spate to assess the Makanya system. The paper finds that improving system efficiency by modernising the diversion and distribution structures in this case is not feasible due to the large amounts of sediments delivered to the system each year. It suggest that instead, investments in conjunctive use of groundwater could be the solution because it involves a relatively small intervention, minimises the physical disturbance of the system, and therefore is likely to respect the existing locally developed water management arrangements.