Contested waterscapes: Irrigation and hydropower in the Great Ruaha River Basin, Tanzania

摘要

This interdisciplinary research examines contemporary discourses regarding causality of hydrological change within the Great Ruaha River Basin, Tanzania. Of particular significance is the allocation of water for upstream rice irrigation in the Usangu Plains, and downstream requirements of the Mtera-Kidatu hydropower system. Tension between these two users was initially brought into focus during the mid-1990s, when low river flows into the Mtera reservoir led to a decrease in hydropower generation. Increasing seasonal water scarcity has subsequently become a normality in the basin. Interviews with actors highlighted a number of causalities for hydrological change. The most commonly cited causalities are an increase in the area and water use inefficiency of traditional smallholder irrigation, which represents the contemporary sanctioned discourse. This is interpreted as an exertion of power by the government and other actors in blaming upstream farmers, setting the limits upon which policies and plans should be pursued. A number of marginal discourses offering alternative explanations are advocated by coalitions of actors. Causalities and management solutions are considered within the water governance arena, determined by institutional arrangements, technical issues, economic and sociopolitical dimensions governing water use and allocation. Water allocation represents a temporal and spatial hydro-political balancing act for the government. On the one hand, promoting upstream agriculture-based livelihoods and sustaining the farmer vote; whilst on the other hand, avoiding downstream hydropower generation failure with associated political ramifications and negative economic consequences. Midstream environmental flow requirements of the Ihefu wetland and Ruaha National Park have been demoted to secondary hydro-political significance. In order to understand actual causalities of hydrological change, studies should be conducted and considered without being subjected to quasi-science and actor appropriation to serve partisan and self-interests. A greater egalitarian approach would help to bring all actors together to promote common management solutions for the equitable allocation of water in the basin.