Water scarcity is a growing issue across the globe (Rijsberman, 2006) and because agriculture is the main consumer of water, investing in irrigation efficiency seems like a good solution to this problem. However, local gains in efficiency can reduce runoff and hence, have an adverse effect on downstream water availability (o.a. Perry (2018, 1999) and Simons et al. (2015)). The core of the water efficiency paradox lies in the positive connotation of efficiency, even though increasing irrigation efficiency can have negative consequences. On this paradox and how basin analysis can be included in World Bank financed irrigation projects. This is done in two parts.

The first part of this research looks into irrigation water consumption in the Amu Darya river basin in Central Asia. With the research question: ‘To what extent is it possible to analyze irrigation water consumption in Central Asia using a locally developed model combined with open source remote sensing data?’. Global open source data for evapotranspiration (ET), precipitation (P), areas equipped for irrigation and storage change are combined with outputs from the Aral Sea Basin management model (ASBmm). These are used to determine the actual irrigated areas, check the model data with water balances and calculate consumed fractions. The results show a trend of increasing CF with increasing irrigated area and larger CFs in downstream areas compared to upstream areas. It shows a big difference (40%) without and with complete reuse of upstream drainage water in downstream irrigated areas. These trends conform to the expectations.

The second part of this study investigates why basin analysis is not structurally included in World Bank financed irrigation projects. Knowledge exchange is crucial for innovation and adopting new paradigms (Filieri et al., 2014; Walter et al., 2007). This is researched with the research question: «\’To what extent can a social capital analysis of knowledge exchange between academic hydrologists, World Bank staff and World Bank water and irrigation consultants aid the incorporation of the basin scale perspective on water consumption in World Bank financed irrigation projects?’. The social capital perspective provides a systematic way to look at the dimensions of knowledge exchange in a social network (Adler and Kwon, 2002). The results from semi-structured interviews are compared to the conceptual framework which was deduced from a systematic literature review.

One of the main obstacles in knowledge exchange and including basin analysis in World Bank financed irrigation projects is lack of time and resources. Proper basin analysis is not conducted because it is not a formal requirement. Additional issues are: ambiguity of the term efficiency, spatial distance between people and differences goals and perspectives within the Bank and between the Bank and client countries. Client countries are leading in project development and the moment the Bank has a background role. The application of basin scale analysis in World Bank financed irrigation projects should be formalized. This does not mean that investments in irrigation efficiency must stop, it means that a basin analysis is necessary to make an informed decision about that investment.