| Irrigation area as part of ensuring national food security, maintaining social stability, spreading advanced technology, promoting rural progress, support economic development, reducing disaster damage, protecting the environment and other aspects, occupies an important place of national foundation and international strategy. Due to the current shortage of water resources, the situation of agricultural water using is more and more severe, water shortage and ecological deterioration are seriously impacting on agricultural production. In the irrigation area, improving water resources development and utilization, allocating scientifically and rationally, improving water use efficiency, are important measures to solve agricultural water crisis, improve the ecological environment quality, and to promote the sustainable development of production.In this paper, from the actual situation of irrigation area, after checked and summarized the researches of agricultural water resource allocation for irrigation area, regarding current issues, based on water allocation, water cycle and coupling theory, the agricultural water resources optimization coupled model in irrigation areas was built. After then, People’s Victory Canal Irrigation District was chosen as the case to validate the feasibility of this model, in order to provide some guidance. The main contents include the following aspects:(1) The construction of the agricultural water resources optimization coupled model in irrigation areas. For properties of irrigated areas, total water consumption minimum was set as the target, underground water and surface water in each period, partitions as the conditions, the actual evapotranspiration, soil moisture in the root zone, and groundwater depth as the constraint, to establish the agricultural water distribution model. The agricultural water resources optimization coupled model was built by coupled the water transformation model and the water allocation optimized model, which was put the time and space scales of data conversion as feature, the irrigation module as a link, and different water-use process as the coupling point.(2) Study area and parameter calibration of water transformation model. People’s Victory Canal Irrigation District was selected as the study area, which means meteorology, soil, topography, geology and other data needed to be collected, to prepare for the MIKE SHE. Choosing evapotranspiration, overland flow, unsaturated flow, unsaturated flow, irrigation and other major modules, Setting appropriate range of simulation and calculation unit, importing data, putting correlation coefficient and Nash efficiency coefficient as evaluation index, based on the 23 observation wells measured data, the model was calibrated in the period of 2009 to 2011, and validated in 2012. The model was reasonable and feasible, which showed fitting result, in the same of groundwater level process of calibration and measured data with the verification period.(3) The application of the agricultural water resources optimization coupled model in irrigation areas. For the features of People’s Victory Canal Irrigation District, the agricultural water resources optimization coupled model was used to analyze respectively three scenarios, which was including the current status, Yellow River water reduction, rainwater utilization, and propose the best deployment plan, at the same time, to provide some guidance.Under three kinds of situations, the final allocation scheme of the total water consumption were 4.33×108 m3, 4.21×108 m3, 4.51×108 m3, reducing 11.22%, 13.66%, 7.47%, and the ratio of well and canal water were 1:3.155, 1:2.192, 1:2.803, which were in the ideal state; During the Groundwater depth process, the trends of the depth were consistency all over the district; The annual actual evapotranspiration was controlled less than 650mm; The average water moisture in root zone was maintained between 10% and 30%, which was suitable for crop growth. The results were significantly improved under all the scenarios after optimization. |
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