Understanding water delivery performance in a large-scale irrigation system in Peru

During a two-year field study the performance of the water delivery was evaluated in a large-scale irrigation system on the north coast of Peru. Flow measurements were carried out along the main canals, along two secondary canals, and in two tertiary blocks in the Chancay-Lambayeque irrigation system. The most important finding was the unexpectedly high accomplishment rate of the actual delivery at field level compared with the on-request schedule. Delivery performance ratios (DPRs) were very close to unity. Three main factors were identified contributing to this good performance: the high degree of accountability of the Water Users' Association towards the water users, the skills and experience of the operators to deal with the - difficult to operate - undershot sliding gates, and the high degree of mutual social control among the water users and their high labour input. It is concluded that the institutional design and skills of operators made a good delivery performance possible, overcoming the difficulties caused by the irregular water supply, infrastructure and on-request schedule. Copyright (c) 2005 John Wiley D Sons, Ltd.