The performance of medium scale jointly managed irrigation schemes in Sub-Saharan Africa : a study of the Wurno irrigation scheme, Nigeria
The subject of `irrigation performance assessment' has grown in importance since the early 1970s. This has been as a result of the increasing realization that irrigation schemes around the world, particularly those in developing countries, do not live up to their expectations. There has therefore been an increasing interest in probing into the operations of existing irrigation schemes in order to understand their strengths and weaknesses, and to developing methodologies and indicators for performance assessment, with a view to improving their performance and water use efficiency. This study presents a conceptual methodology and performance indicators for evaluating the performance of medium scale irrigation schemes in Africa with joint participation between smallholder farmers and an irrigation agency. The proposed methodology provides a logical sequence of the main processes involved in irrigation performance assessment with emphasis on the 'whole system' or 'farming system' approach. Performance indicators have been proposed which relate to the inputs, processes of transformation, and outputs, which is a marked variation from existing approaches which focus only on the evaluation of outputs. The indicators describe qualitatively and quantitatively the level of attainment of the objectives of an irrigation scheme, or parts thereof. The methodology and concepts outlined in the first part of this work are applied to study the operation and performance of the Wurno Irrigation Scheme, Nigeria, a typical formal medium scale jointly managed irrigation scheme in sub-Saharan Africa. The results of the case study show the performance of the Scheme to be unsatisfactory. This raises questions regarding the views of international lending agencies and governments of developing countries who are looking to smaller, as opposed to large, scale irrigation schemes as the way forward. The study argues that the critical issue is not that of size per se, but the linkages between the primary characteristics of the physical design of the irrigation infrastructure, and the structure of the organizational and institutional arrangements for the operation and management of the scheme.