Study And Comoarisons On The Vulnerability Of Karst Water Resources System And Its Evaluation Methods

Global environment has changed as a result of the change of global climate and rapid socio-economic development.It is an important part of current researches on the vulnerability of water resources that the stability of the water resources system has been destroyed due to the influence of external environment,which causes the deterioration of water quality and water quantity and the exacerbation of flood and natural disasters.The karst area is rich of water resources,but due to the specific hydrogeological structure,fragile ecological environment as well as concentrated human activities on its underlying surface,the stability of its water resources system has been affected to a certain extent.Karst water resources are the main bridge contributing to the sustainable development of socio-economic and ecological environment in the karst area.However,there are few researches focus on the vulnerability of water system in the karst region.Therefore,this dissertation studies the vulnerability of karst water resources system based on systematic theory and previous researches,discussing the basic theory of the vulnerabilityof karst water resources system and selecting the most applicable method among three common methods of water resources vulnerability.At last,it proposes a few suggestions on the management mode of karst water resources system.Its main research contents and conclusions are as follows:(1)It attempts to elaborate the concept and connotation of the vulnerability of the karst water resources system combining with the characteristics of the karst environment and water resources system.Based on the results of previous researches,the author analyzes the impact factors through the driving force,pressure,state,influence and response of water resources system.According to DPSIR conceptual model and the construction principles of evaluation index system,seventeen indicators are selected to evaluate the vulnerability of karst water resources system.(2)Choosing Guiyang as an experimental area,the author evaluates and compares the vulnerability of its water resources system from 2006 to 2015 based on set pair analysis method,fuzzy comprehensive evaluation method as well as projection pursuit method.It turns out that the methods focus on different aspects separately,among which the set pair analysis method is more applicable to the vulnerability assessment of waterresources system in karst regions due to the objectivity and practicality of its evaluation results.This may be attributed to the characteristics of the karst water resources system and set pair analysis method which is suitable for the study on the interactions of certainty and uncertainty in the system.(3)It analyzes the trend of vulnerability of the water resources system in Guiyang from 2006 to 2015,and explores how the socio-economic and ecological environment influence the water resources system in the karst region.(4)It evaluates and compares the vulnerability of water resources systems between karst and non-karst regions.The study shows that the vulnerability levels of water resources systems in Guiyang,Bijie,and Qiandongnan in 2015 were judged to be mildly vulnerable,moderately vulnerable,and invulnerable.The characteristics of the karst natural environment lead to the potential vulnerability of the regional water resources system.Meanwhile,social and economic activities as well as scientific and technological level in human society are the main factors driving the transformation of the potential vulnerability and the actual vulnerability of the water resources system.Therefore,in the study of vulnerability assessment of karst water resources system,wemust pay attention to the analysis of the impact mechanism of natural environment,anthropic social and economic activities and scientific and technological level of karst area on the vulnerability of karst water resources system.(5)During the assessment,it is necessary to take in evaluation index such as ratio of karst distribution area,forest coverage rate,capacity of water conservancy,proportion of groundwater resources,water quality standards,population density,per capita GDP as well as water consumption per 10 000 GDP,so that the indicator system can lay stress on the characteristics of the karst region,and can be more practical.(6)Aiming at those water safety issues in the karst region mentioned above,the author proposes a management model of water resources in the karst region and provides scientific and reasonable suggestions so that the issue of vulnerability of the water resources system in the karst region can be alleviated instantly or in the near future.