The value of performance studies of irrigation projects for lending agencies

This paper looks at the World Bank's experience with irrigation and drainage projects and compares their performance expected at appraisal stage with the performance re-assessed at completion and at the time of impact evaluation, typically 3 to 5 years later when projects have reached their full potential. This review confirms the over-optimistic assumptions of project performance at appraisal and completion stages. The deficiencies in water distribution are far greater than suspected, affecting cropping intensity and crop yields much more than originally thought. An important lesson from this memo is the need to adopt more realistic values of key parameters in the preparation of irrigation projects.