Study On Water Use Planning And Water Distribution Pattern Of Main Canals In Huailian Irrigation District

Since the 21st century,the Central Document No.1 has focused on the work of’agriculture,rural areas and farmers’ for 19 consecutive years,especially the opinions of the Document No.1 on the key work of comprehensively promoting rural revitalization in 2022,which pointed out that food production and supply of important agricultural products should be fully guaranteed,the basic support of modern agriculture should be strengthened,and the bottom line of national food security should be firmly kept.Large-scale irrigation districts are an important infrastructure for agricultural and rural economic development.After decades of continuous construction and water-saving transformation,they have become important production bases of agricultural products in China,and effectively promoted social and economic development,which ensured food security and effective supply of major agricultural products.They are of great significance in promoting agricultural production and increasing farmers’ income.Huailian Irrigation District is a large-scale irrigation district built in 1958,located in Huai’an City,Jiangsu Province.During the growth period of rice every year,high temperature weather usually lasts for a long time,so irrigation water quantity is relatively large and concentrated,which leads to the contradiction of temporal and regional water supply being prominent.Therefore,in order to effectively improve the guarantee rate of irrigation design and effectively alleviate the contradiction and dispute of local water use,it is of great guiding significance and application value to carry out the research on water use planning and water distribution pattern of main canals in Huailian Irrigation District,which provides technical support for the upgrading and modernization of irrigation area,the scientific irrigation and water distribution,and the automation control of backbone engineering.The main research contents and results include the following three aspects:（1）According to the long series of precipitation data from June to September in the irrigation area from 1981 to 2017,the theoretical frequency curve was obtained by using the hydrological statistics method.Based on this,the representative years of different hydrological years were selected,and the irrigation schedules of rice in four hydrological years（25%,50%,75%and 95%）were calculated by using the design representative year method and water balance principle.（2）According to the irrigation water utilization coefficient and the rice irrigation area controlled by the main canals along the general main channel in different level years（present 2018,recent 2025 and long-term 2035）,under 12 scenarios generated by the combination of 3 level years and 4 hydrological years,the irrigation water plans for different growth stages of rice in the areas controlled by the main canals（including the hanging bucket canal）were given respectively,which provides a basis for the scheduling and management of the main water sources in the irrigation area.（3）Based on the generalization of the main canal system in the irrigation area,the MIKE11 software was used to simulate the change process of cross-section water level along the general main channel with time under different hydrological years and different water distribution modes（including the water quantity distribution,and different working modes of the four main canals）in view of the current level year.The corresponding flow change processes at the head of the four main canals with time were also simulated,which provided technical support for the irrigation area to respond to the dynamic response of the automatic operation of the head gates of the main canals（including the opening time,duration and degree of gates）under different hydrological years and different water distribution modes.At the same time,the result lays the foundation for the construction of digital twin platform and intelligent management of irrigation area in the future.