Research On The Impact Of Irrigation On Groundwater And Groundwater Regulation And Storage Utilization

As a typical canal and well two-irrigation district, Jinghui irrigation district made a great contribution to the agricultural production of Guanzhong Region. In recent years, because of the water shortages, imperfect management structure, unreasonable irrigation water and groundwater overdraft, the groundwater level in the irrigation area continues to decline, and bring about a large area of greater depth and cone of depression. Therefore,the paper adopts the method of combining the field experiment and theoretical research, unions the moisture content of soil water and groundwater level monitoring test under different irrigation conditions in Jinghui test site and Visual Modflow 3d visualization softwareto research the evolution law of different irrigation water on groundwaterunder the condition of large buried depth. On this basis, combineing with hydrogeological conditions and groundwater dynamic datairrigation district,analyzedsystemly the necessity and feasibility of the groundwater regulation and storage in irrigation area, set up three kinds of groundwater regulation and storage scheme, and used the numerical simulation model to analysis the groundwater level dynamic and the status of the water balance under different regulation and storage scheme. The results of thesis are as follows:(1) Selected 7253.7 acres of land of the 12,15 and 16 bucket of the third lateral canal in Jinghui irrigation district as the experimental field test area to study therecharged lawof irrigation on groundwater under the condition of large buried depth.(2) Through the monitoring test of the moisture content of soil water and groundwater level under the condition of different irrigation water in Jinghui test site,we backstepped the irrigation infiltration coefficient under the condition of large buried depthto determine the irrigation on groundwater recharge conditions under different irrigation water. The irrigation infiltration coefficient of Jinghui irrigation district under the condition of large buried depth is 0.0875.(3) Based on the principle of soil dynamics and water balance theory, using Visual Modflow 3d visualization software simulated and verified the influence of irrigation on the groundwater level and the status of the water balance under the condition of different irrigation water.The results show that, during the spring and summer irrigation, supplying water to soil is insufficient to satisfy the crop growth, alsodraw a little amount water from the groundwater system, but the irrigation water is enough during the winter irrigation. So during the spring and summer irrigation, the district need to increase the leading of surface water.(4) From Precipitation, the surface and groundwater resources, groundwater dynamic, hydrologic conditions and the optimum ratio of water drainage wellsto analysis the irrigation area water environment, we found that the precipitation and surface water resources all showed a trend of decline from 1980 to 2010, negative equilibrium in different level years continue to grow and the the ratio of water drainage wells was unfitin the past 30 years. So it is imperative to regulation and storage the groundwater in irrigation district.(5) From the aspects of regulate the formation, the headwaters, the ways and the capacity of reservoir, comprehensive,we discussed the feasibility of groundwater regulation and storage in irrigation district, then set four kinds of groundwater storage schemes including benchmark schemeto explorewhich scheme can extremely recover the groundwater level to reasonable depth, then determine the best groundwater storage scheme.