A framework for the definition of irrigation water equity and its application in small-scale systems in Tanzania

Water equity is a key priority for the provision of water services and stands as one the three pillars of Integrated Water Resources Management. Potable water supply and sanitation attract growing attention regarding equity of access and its implications for wellbeing, health and poverty, as reflected in the 2016 United Nations Sustainable Development Goal Number 6. By contrast, the concept of water equity remains ill-defined in relation to irrigation, despite accounting for 70 percent of the world’s freshwater withdrawals. Based on a thorough literature review, this study develops a new conceptual framework for the definition of irrigation water equity, based on eight key aspects. Under this new optic, institutional frameworks in the United Republic of Tanzania are examined to understand how the multiple dimensions of water equity affect irrigators within traditional schemes. While volumes are the cornerstone of formal irrigation equity principles, water deliveries within farmer-managed systems are rarely accounted, due to lack of human and technical capacity. Instead, practical evidence gathered during this study reveals that smallholders are most concerned about other equity dimensions, which are not yet recognised by formal or customary rule systems. These include timing and reliability of supply; barriers in accessing decision-making institutions; and inconsistent application of rules and penalties across varied socio-economic strata. This study argues that, in Tanzania, as in other developing countries, a comprehensive and consistent definition of irrigation water equity -across national, regional and local levels- would assist smallholders in managing their resources in a more equitable manner.