Study On The Model Of Regualting Groundwater Irrigation Carrying Capacity On The South Bank Of The Yellow River In Inner Mongolia

As the source of life,water contains dual attributes,both basic natural resource attributes and strategic economic resource attributes.However,due to the differences in geographical location,climate change and human mining activities have a negative impact on the water cycle process,resulting in a series of problems such as differences in the distribution of water resources,serious water pollution and shortage of water resources,which have a serious negative impact on national economic development and people ’s lives.As an important water supply source for urban domestic water,industrial water and farmland irrigation water,groundwater plays an important role in regional economic and social development.With the development of the national economy and the improvement of living standards,people ’s demand for water has increased rapidly,and the amount of groundwater exploitation has increased year by year.However,due to the lack of reasonable planning and scientific management and control of groundwater development,groundwater has been over-exploited in some areas,and the water level has continued to decline,causing ecological degradation,land subsidence,water pollution and other ecological and environmental problems.At the same time,due to the lack of overall planning and system protection,the groundwater carrying capacity is gradually decreasing,and the groundwater ecological environment is facing many severe tests.This study aims to improve the groundwater irrigation carrying capacity of the south bank of the Yellow River in Inner Mongolia(Otog Banner as an example).Based on the evaluation of the groundwater irrigation carrying capacity of each Gacha in Otog Banner,the area with the lowest groundwater irrigation carrying capacity was selected as the research area,and the groundwater numerical simulation model was used to determine the available amount of irrigation water in this area.On this basis,a multi-objective optimization configuration model was used to construct a regional groundwater irrigation sustainable utilization combination plan,which provided a scientific basis for improving the groundwater ecological environment and formulating a reasonable groundwater resource development and utilization strategy.(1)Based on the established evaluation index system of groundwater irrigation carrying capacity,the groundwater irrigation carrying capacity of each Gacha in Otog Banner was comprehensively evaluated by using the method of entropy weight coefficient-analytic hierarchy process.The conclusions are as follows :(1)There are three Gacha with groundwater irrigation carrying capacity evaluation grade I(ideal state),accounting for 4.17 % of the total;there are 52 Gacha with grade II(bearing),accounting for 72.22 % of the total number of Gacha.There are 17 Gacha with evaluation grade III(weak bearing),accounting for 23.61 % of the total.(2)The best groundwater irrigation carrying capacity is Bagaer and Tugacha,the bearing capacity score is 0.8405,and the evaluation grade is grade I(ideal state).(3)The worst groundwater irrigation carrying capacity is Saiwusu grass seed field,the bearing capacity score is 0.4628,and the evaluation grade is grade III(weak bearing).(4)The average comprehensive score of the bearing capacity of each Gacha is 0.6741,and the average bearing capacity evaluation grade is III(weak bearing).(2)Based on the evaluation of groundwater irrigation carrying capacity,the Saiwusu irrigation area with the worst carrying capacity is selected as the research area.Based on the groundwater numerical simulation model under the condition of overexploitation,the groundwater numerical simulation model under the condition of non-overexploitation is established,and the groundwater recoverable amount was calculated to be 31990425 m~3.The amount of available irrigation water is 31392462 m~3.(3)The multi-objective optimal allocation model is constructed,and the model is solved by the NSGA-II algorithm to obtain the best optimal allocation scheme of groundwater resource allocation in the study area.The scheme adopted three measures:planting structure adjustment,planting mode adjustment,and water saving with chemical.(4)By comparing the groundwater irrigation carrying capacity of Saiwusu Irrigation District in the base year and the scenario year,it can be seen that the groundwater irrigation carrying capacity score based on the base year is 0.5765,and the evaluation grade is grade III(weak bearing).After adopting the best optimization scheme,the groundwater irrigation carrying capacity score in the scenario year is 0.7060,and the evaluation grade is grade II(bearing).Therefore,the effect of groundwater irrigation carrying capacity in the irrigation area after adopting the optimized configuration scheme is better.Compared with the carrying capacity score before the scheme is not adopted,the carrying capacity score is increased by 0.1295,the increase range is 22.46 %,and the carrying capacity level is increased by one level.