Improving management scenarios of water delivery service in collective irrigation systems: a case study in Southern Italy

The performance of water delivery service in collective irrigation networks can be enhanced by improving measures ranging from a better water allocation to more expensive structural works. In any case, the efficacy of these measures must be simulated prior to their actual implementation and evaluated using quantitative performance indicators. The aim of this study is a strategic analysis of the water delivery service to understand whether a better water allocation is possible in collective irrigation systems by implementing improving measures at lower cost compared to structural works. For this goal, the performance of three water delivery systems was evaluated in Calabria (Southern Italy) over four irrigation seasons, using the indicators of adequacy, efficiency, dependability and equity developed by Molden and Gates (J Irrig Drain Eng ASCE 116(6):804–823, 1990). Subsequently, three scenarios for improving irrigation management (replacement of sprinkler methods with micro-irrigation, an arranged-demand water delivery service together with an irrigation advisory service, and a combination of both actions) were simulated and evaluated. Furthermore, two new indicators (“User Satisfaction Index” and “Water Exploitation Index”), measuring satisfaction of irrigation service users and water use levels, were proposed and applied. In the current situation poor adequacy, reliability and equity of water delivery service with low user satisfaction together with fair efficiency in exploiting the limited irrigation resources were detected. The simulation of an arranged-demand distribution and irrigation advisory service was found to be more efficacious and favourite to the system users than the replacement of current sprinkler systems with micro-irrigation. The combined adoption of these scenarios is advisable, to assure the optimal performance in water delivery systems and to make the collective service more adequate and efficient for both irrigation users and managers.