Assessing irrigation performance with comparative indicators : the case of the Alto Rio Lerma irrigation district, Mexico

This report advocates complementing process indicators with a minimum set of comparative indicators to assess the hydrological, agronomic, economic, financial, and environmental performances of irrigation systems. In support of this thesis, comparative indicators were applied to the Alto Rio Lerma Irrigation District (ARLID) in Mexico, as well as to two modules within the district. The results and data collection procedures of the comparative indicators were compared with those of a small set of process indicators. Assessment of ARLID with comparative indicators points to irrigation management under conditions of relatively abundant water availability, planned irrigation depths that are high relative to crop requirements, economic outputs per unit of water and land that are favorable compared with those of other districts, full recovery of operation and maintenance (O&M) costs, and overexploitation of the aquifers. The application of process indicators at district and module levels, as well as at the level of selected canals and fields, provided good insight into the processes and dynamics of system management. Results indicate that actual water allocation at the district level closely follows the volumes concessioned to the modules and that there are few problems related to timeliness and spatial distribution of water delivery within the selected canals. In all cases observed, actual irrigation supply to canals and fields was higher than planned and reported. An important advantage of using the process indicators was that it provided an opportunity to cross-check the reliability of the district data used to develop the comparative indicators. The application of comparative indicators was less time- and resource-intensive than the procedure for collecting primary data for the process indicators. Yet it proved to be more complex than was anticipated, mainly due to the need to collect and aggregate data at lower system levels to cross-check aggregated district-level data; also, several problems were encountered with the calculation of the indicators. Once these methodological problems have been resolved, the minimum set of comparative indicators will be a useful and cost-effective instrument for monitoring outputs and impacts of irrigation management, as well as for providing a good basis for correlating type and quality of process performance with comparative performance. Includes references. (Author abstract, modified)