Assessment Of Groundwater Sustainability Using Multi-indicators In The Hohhot Plain

In recent years, with the rapid social and economic development, an increasingly serious problem of water resources occurred in Hohhot, the capital city of Inner Mongolia Autonomous Region. In Hohhot plain, intensive abstractions of groundwater lead to depletion of shallow aquifer and a water depression cone in confined aquifer. Such serious environmental geological problems presented severe challenges to groundwater resources on urban sustainable development.This thesis selected sustainability assessment as the starting point by the DPSIR (Driver Pressure-State-Impact-Response) framework of indicators assessment theory, the indicators system of groundwater sustainable evaluation was built through theoretical analysis, numerical laws of statistics and other methods in Hohhot. Considering the respects of natural conditions, socio-economic development and environmental and geological constraints for indicator frame, indicator evaluation weight was determined by utilizing analytic hierarchy process and information entropy method. Then through indicators integrated analysis methods, it assessed groundwater state and groundwater sustainable levels and trend under different mining plans.Through evaluation and analysis, it obtained following conclusions:(1) It introduced the indicators system of sustainability evaluation of groundwater, and applied for assessment of groundwater resources sustainable utilization in Hohhot plain. According to the existing problems of groundwater resources in Hohhot, the system was established under the DPSIR framework to address the practical problems and by analysis and mathematical statistics methods, these indicators were filtrated for evaluation.(2) It created a method to calculate indicators weight by jointing analytic hierarchy process and information entropy method. The weight of groundwater sustainability assessment indicators was the core process and mostly determined the evaluation results. Compared with single method, it was a more reasonable method to determine weight, reducing man-made error and quantization error from actual condition.(3) It analyzed the spatial distribution of groundwater sustainable level and its reason under present state in Hohhot plain. Assessment results showed that, there was a big difference on spatial distribution of groundwater sustainability. In urban area and western economic development zone, the level was the worst, and the contrary in the Piedmont recharge area, Big Black River upstream region. From the spatial distribution trend analysis of environmental geological problems, overexploitation led to more severe problem in south-east because of big aquifer thickness and easy surface subsidence; located at Heihe downstream, water quality was relatively poor due to easily be polluted by upstream, and resource utilization level was lower, so this area is prominent in resources and environment problems during regional development.(4) Groundwater sustainable variety and rule were predicted and analyzed, combining the "twelfth-five" plan and groundwater utilization scheme of the study area.. In view of the overdraft problem and mining scheme, it analyzed the assessment results of2015and2020two periods, which demonstrated the trend was benign in more than half area of the research region. It could achieve better effect by scheme of planar compression comparing to by scheme of concentration compression. From the trend analysis result, the sustainable level was poor in double aquifer structure zone than in monolayer structure area, providing direction for groundwater resources planning.(5) Zoning method of groundwater resources sustainability assessment was developed, and made it more reasonable in lateral correlation of groundwater sustainability in different study region. Based on sustainability assessment, by cumulative distribution function of data from evaluation, the division was made depending on groundwater sustainable assessment result in current year, and reasonable exploitation and utilization suggestions were proposed about each division.