سیستم پشتیبانی تصمیم گیری مبتنی بر وب برای مدیریت آبیاری کانال Web-based decision support system for canal irrigation management

1. Introduction China is facing severe water scarcity while the demand keeps increasing and distribution of water resources is spatially and seasonally uneven. Although the total fresh water volume in China is large in absolute value, ranking sixth in the world, the per capita water resource is only 25% of the world average. In the past 10 years (2006–2015), the Chinese average total water consumption was 601.4 billion m3 , 62.5% of which is agricultural water consumption (“China Statistical Yearbook-2015,” 2015). Therefore, conserving water in agriculture is important for both water and food security for China. With urbanization and enhanced living standards, the amount of water used for domestic and industrial purposes has also increased (Peng, 2011). Increasing the efficiency of water use in irrigation practice is important for ensuring the sustainable development of agriculture. However, the lack of practical methods of irrigation management results in substantial waste of irrigation water and labour. Surface irrigation using canals is the main method of water application in paddy rice irrigation systems in Southern China. Owing to the constraints of canal water delivery capacity, irrigation often has to be rotated, and it usually takes several days to complete one round in a large irrigation system. Uncertainty of rainfall and difficulty of monitoring overall field water availability complicate the irrigation practice. Unexpected rainfall and underestimated actual field water availability will lead to the wastage of labour, water, and energy. An irrigation decision support system is a platform developed for irrigation water management. It can improve irrigation efficiency and reduce labour inputs in daily irrigation management with a few added engineering services. Furthermore, adopting the latest technology in agricultural practice is also meaningful. The influence of rainfall uncertainty on irrigation decisions can be improved with the help of weather forecast information (Gowing and Ejieji, 2001). Daily reference evapotranspiration (ET0) prediction using the public weather forecast information can be adopted for real-time water allocation and irrigation management (Cai et al., 2007, 2009; Luo et al., 2014).