Study On Numeric Simulation And Reasonable Irrigation Mode In Shi Jin Irrigation District

In Hebei province, the water resources of the groundwater is shortage. Exploitation of groundwater was overloaded seriously. These reasons caused that the declining of the underground water level, the expanding of the groundwater funnel area, the settlement of underground water, and a series of ecological problems. Right now in Shi Jin irrigation district of Hebei province, the groundwater level descends continuously. This article accorded to the numeric simulation principle and the finite-difference methods, and a 3D transient surface-groundwater interaction model was developed using the MODFLOW part of Visual MODFLOW in Shi Jin irrigation district of Hebei province.On the basis of hydrogeology condition, recharge, run off and excretion conditions, dynamic features of groundwater and distribution status of groundwater mineralization are analysed of study area. Secondly, hydrogeological parameters in study area are determined. Then, the balance between recharge and excretion of shallow groundwater quantity is analysed. Thirdly, based on the discretization and hydrogeological condition generalization in study area, the hydrogeological conceptual model and groundwater mathematical model in Shi Jin irrigation are established, which is solved by Visual MODFLOW software. In the following, the established model is identified and validated by the water lever datum of 2013. The results show that the model accords with precision requirements and better reflects actual hydrogeological conditions of the study area and dynamic change law of groundwater. It can be used by predicting groundwater dynamic changes.On the basis of the above work, the model was used to predicting groundwater dynamic changes in Shi Jin irrigation district in the next 10 years. It is concluded that the underground water level continuing. Under of this conditions,the groundwater exploitation is unsustainable.Considering the the present situation of the irrigation district, the MODFLOW software was used to predict the groundwater table of future. It was under the condition of water-saving irrigation mode and the south-north water diversion project. It is concluded that: when the channels of the irrigation district were best transformed, the ground water table decreased about 3 m; when the low pressure pipeline irrigation was used in all of the irrigation field, the ground water table decreased about 1.7 m; when the channels of the irrigation district were best transformed and the low pressure pipeline irrigation was used in all of the irrigation field, the ground water table decreased about 1 m.When the south-to-north water transfer project water was used, the ground water table increased about 0.4 m; when the south-to-north water transfer project water was used and the channels of the irrigation district were best transformed, the ground water table increased about 1 m; when the south-to-north water transfer project water was used and the low pressure pipeline irrigation was used in all of the irrigation field, the ground water table increased about 2.2 m; when the three kinds of measures were complicated in the same time, the ground water table increased about 2.8 m.In conclusion, basing on the above analysis of the data and considering the actual situation of the irrigation area, the Shijin irrigation district should change the irrigation mode to control the groundwater table and to promote the sustainable development of the irrigation area.