Health Assessment And Evolution Of Water Cycle In The Main Urban Area Of Handan City

With the climate change and the rapid development of human society,the global environment has undergone tremendous changes,resulting in a series of water problems such as water shortage,intensified contradiction between supply and demand,serious water pollution and water ecological degradation.The essence of this is the interference effect of human activities on the natural water cycle,and it is an unhealthy manifestation of the “natural-society” dualization of the water cycle.Therefore,in the situation that the water cycle has been dualized,it is the key to solve the above-mentioned series of water problems that how to “put the veins” on the health of water cycle.In the paper,the main urban area of Handan City in North China Plain was selected to evaluate the health assessment of the regional water cycle in the past 12 years,which is of great representativeness and is seriously interfered by human activities and has poor natural endowment of water resources.The main research contents and results are as follows:(1)Starting from the water cycle process and connotation,the concept of healthy water cycle was explained based on the analysis of the evolution process of the "natural-society" binary water cycle and the characteristics of urban water cycle process,which were compared with other similar concepts between similarities and differences;(2)Nineteen evaluation indicators and five dimensions(water source,water supply,water use,drainage and reuse)were selected,based on the interpretation of the concept of healthy water cycle and the key performance indicator method(KPI).The weights of each dimension and each index were calculated through the analytic hierarchy process.According to the characteristics of the water cycle in northern cities,and the thresholds of each index were set with reference to relevant norms,standards and research results.Finally,a water cycle health assessment system for the northern urban areas was constructed.(3)The comprehensive index method was used to calculate indicators,dimensions and comprehensive scores,and the corresponding health levels of different indicators and dimensions were evaluated.The results show that: in general,the water cycle process in the main urban area of Handan City experienced a trend of deterioration and then rebound.And it was in a sub-health state from 2005 to 2015.Among them,2006 is the lowest year of health and also a turning year.Since 2007,it had been presented a state of steady rise in the twists and turns.And in gradual it returns to health state in 2016.(4)In terms of health assessment of each dimension in 2016,the score of water use dimension is highest,4.68,which was in a healthy state and affected the score of the overall evaluation in 2016.However,the score of the reused dimension is the lowest,2.88,and still in a pathological state.Then the main factors affecting the water cycle health in the main urban area of Handan City were analyzed according to the evaluation results,and reference suggestions of five water cycle processes,namely,water source,water supply,water use,drainage and reuse were put forward.The above results could provide background support for the construction of water ecological civilization in Handan City,provide a strategic basis for solving local water problems,and provide decision-making reference for sustainable development of local and even northern cities.