A Comprehensive Evaluation System for Water-saving Irrigation Projects

【Objective】 Implementation of saving-water irrigation is a strategy affecting not only crop growth but also many other aspects directly or indirectly. How to comprehensively evaluate its consequence is an issue that remains largely elusive. The purpose of this paper is to fill this knowledge gap. 【Method】 A comprehensive evaluation system for water-saving irrigation projects was constructed, with its impacts on technical aspect, socioeconomic aspect, and ecological and environmental aspect taken into account. It considered irrigation precision and intelligence, economical return, and consequence for ecology and carbon; the evaluation system was built based on literature review, content analysis and knowledge management reconstruction. The precision includes effective utilization of irrigation water, irrigation uniformity and implementation of water measurement technologies; the economy includes crop yield increase, investment return, and timely payment for water bills; intelligence includes convenience of operation and management of irrigation project, as well as soil-moisture monitoring network; ecology includes vegetation coverage, soil salinization, surface water and groundwater improvement; carbon includes land and energy saving. We applied the model to three >10 000 mu (1650 acres) irrigation districts with smart irrigation system in Gansu, Ningxia and Qinghai province, respectively. 【Result】 In Qinghai province, the unattended and remote-control photovoltaic water lifting and micro-irrigation district improved photovoltaic water lifting efficiency and irrigation uniformity, thereby increasing comprehensive water efficiency by 32.8%. In Gansu province, implementation of the intelligent scheduling of canals with integrated gates for measurement and control increased the comprehensive water efficiency by 26.6% due to the improved irrigation automation, reliability of measurement, timely payment for water bills, and reduction in energy and labor. In Ningxia, the improvement in flow matching of pumping station units and extended water networking link increased its comprehensive water efficiency by 27.5% due to the enhanced water supply, water saving irrigation guarantee. 【Conclusion】 Constructing modern irrigation districts needs a comprehensive evaluation system to evaluate its impact not only on crops but also on many other aspects such as automatic monitoring of soils and crop traits, intelligent control and precise scheduling of the irrigation projects.