Water Productivity Over Scales in Zhanghe IrrigationSystem

摘要

China has pioneered the water saving irrigation (WSI) techniques for rice andthe techniques have been widely adopted over large areas. However, a question of globalinterest is whether this on-farm practice has led to water “real” savings, which can betransferred to other agricultural and non-agricultural uses. By better understanding howfarmer practices and other interventions “scale up”, a typical large-sized irrigation system,Zhanghe Irrigation System (ZIS), located in the Hubei Province north of the Yangtze Riverwas selected for the research and we considered water use at different scales— farmers’fields, a mezzo scale, a main canal command scale and, finally at the irrigation system orsub-basin scale. Based on the analysis of two years’ experimental data and long-termdata on flow records, cropping area and crop yield in various sections of ZIS, the paperquantified the water productivity with and without WSI techniques at different scales anddescribed the trend of water productivity over time. The factors behind the increase inwater productivity at ZIS were explored. The water accounting methodology and relatedindicators developed by the International Water Management Institute (IWMI) wereapplied to ZIS to evaluate the status of water use and productivity at different scales.