Research On Water Ecological Environmental Assessment Based On The Concept Of "Water Resources, Water Environment, Water Ecology And Water Disasters Co-governance"

The water ecological environment is closely related to human survival and social development.With the rapid development of human society,the water ecological environment has been greatly affected.The shortage of water resources and the low level of conservation and utilization,the decline of water environment quality,the destruction of water ecology,and the prominent problem of water disasters are frequent.Therefore,scientific evaluation of water ecological environment quality is of great significance to the sustainable development of human society.In this paper,combined with the concept of " four water treatment," the relevant indicators are selected from four aspects : water resources and conservation and utilization level,water environment quality,water ecological quality and stability,water disaster and prevention and control ability.Combined with variable fuzzy recognition theory and scoring method,the water ecological environment evaluation model is constructed and applied to Qingjiang River Basin.The main conclusions are as follows :(1)Combined with the water control concept of ’ four water treatment at the same time ’,a water ecological environment evaluation index system with 3 levels and 38 indicators was constructed.In the selection of evaluation indexes,the three indexes of flow rising times,average duration of flow rising and flow reversal times in IHA index system are used to evaluate the quality and stability of water ecology.(2)Combined with variable fuzzy recognition theory and assignment method,a water ecological environment evaluation model based on ’ four water treatment ’ was constructed.The subjective and objective weights of each index are determined by analytic hierarchy process and space vector theory,and the comprehensive weight is obtained by coupling the subjective and objective weights by the minimum information entropy method.The grade standard of the evaluation model is determined.(3)The RVA method was used to analyze the impact of water conservancy projects on the water ecological environment of the Qingjiang River.During the construction period(1987 ～ 2008)of the water conservancy project in the Qingjiang River Basin,the hydrological change degree was 46.19 %,and the hydrological change degree in the comprehensive utilization period(2009 ～ 2020)was 64.33 %,which was moderate change.The construction and operation of the water conservancy project had an impact on the water ecological environment of the Qingjiang River Basin.(4)The water resources and conservation utilization level,water environment quality,water ecological quality and stability,and water disaster and prevention and control capacity of the Qingjiang River Basin were analyzed.The results showed that the water resources and conservation utilization level,water environment quality,water ecological quality and stability quality of the upper and lower reaches of the Qingjiang River were improved.The quality of water disaster and prevention and control capacity was greatly affected by the intensity of flood and drought disaster and the affected area of flood and waterlogging disaster in the basin,but the compliance rate of embankment in the basin was on the rise,and the flood and waterlogging disaster prevention capacity in the basin was improved.(5)The water ecological environment evaluation index model of ’ four water treatment ’ concept was applied to Qingjiang River Basin.The evaluation results of the variable fuzzy recognition model show that the water environment quality in the lower reaches of the Qingjiang River increased from 0.599 to 0.765,and the water environment quality in the upper reaches of the Qingjiang River increased from 0.555 to 0.716.The evaluation results of the scoring model showed that the overall water ecological environment score of the lower reaches of the Qingjiang River increased from 62.6 to74.1,and the water ecological environment quality score of the upper reaches of the Qingjiang River increased from 54.0 to 74.3.The overall water ecological environment of the Qingjiang River Basin showed a gradual improvement trend.The evaluation results of the variable fuzzy recognition model are close to the evaluation results of the scoring model,which are consistent and reasonable,and can provide corresponding scientific basis for formulating reasonable water ecological environment governance measures.