Study On Comprehensive Evaluation Of Water Resources-Water Environment Carrying Capacity In Hangzhou Main District

Water is an important basic material for human survival and an indispensable strategic resource for urban development.As a key core city within the scope of the Yangtze River Delta urban agglomeration and the Greater Bay Area around Hangzhou Bay,Hangzhou City must not only have a strong economic base and demographic dividend,but also have considerable material resource reserves.At present,the rapid expansion of Hangzhou's urbanization process will increase the contradiction between supply and demand of regional water resources and increase the pollution of the water environment.How to solve such problems of water resources and water environment is essential for maintaining the social and economic development of the city.This article takes the main district of Hangzhou as the research object,on the basis of referring to a large number of documents,sorts out the concept development of water resources and water environment carrying capacity at home and abroad,summarizes related research methods;selects the principal component analysis method for comprehensive evaluation of water resources carrying capacity,Introduce the concept of water resources security for further evaluation and analysis;adopt the analytic hierarchy process-entropy weight method to evaluate the water environment carrying capacity;combine the water resources and water environment carrying capacity evaluation values for comparative analysis,find the connection between the development of the two,and propose improvements Relevant suggestions for water resources,water environment carrying capacity and industrial development.The main research contents and conclusions are as follows:(1)In terms of water resources evaluation,the principal component analysis method was used to evaluate the water resources carrying capacity in the study area from 2007 to 2017.The water resources carrying capacity in the core urban areas of Hangzhou differed significantly in different time periods.From 2007 to 2017,the comprehensive principal component score increased from-1.38 to 0.49.Except for 2011,2014 and 2017,which were affected by the decline in the total amount of water resources,there was a slight fluctuation in water resource carrying capacity(compared to the same period of the previous year,the total amount of water resources fell by 32 %,29 %,and 32 %).trend.The comprehensive index evaluation method was used to evaluate water resources security.From 2007 to 2017,the water resource security status of Hangzhou's core urban areas was in general and poor status,and the recent poor status occurred more frequently,and the trend of future water security status is downward..Through the analysis of both carrying capacity and water resources security,the same result is obtained,that is,the water resource pressure in the core urban area of Hangzhou will increase year by year in the future,mainly affected by the three major indicators of water resources,water environment pollution,and social economy.(2)In terms of water environment evaluation,the analytic hierarchy processentropy weight method is used to evaluate the water environment carrying capacity from 2007 to 2017,and the spatial-temporal changes of water environment carrying capacity are analyzed by three indicators: water surface rate,water control index,and water quality index.The overall development of the carrying capacity of Hangzhou's core urban areas fluctuated greatly,showing a positive "V" type development.The lowest and highest years of carrying capacity were 2010 and 2017,with scores of 55 and 80 respectively,mainly affected by water surface rate and water quality.2017 The water surface rate was 8.5 % overall,but it was only 6.6 % in 2010;the water quality fluctuation was the most obvious.The proportion of the four types of water quality and above from 2007 to 2017 was reduced from the highest(2010)of 72.5 % to the lowest 25.9 %(2017),The water environment of the river has been greatly improved.The spatial distribution of the water environment carrying capacity is in three grades.The overall water environment carrying capacity of the main cities of Binjiang and West Lake,the Xiaoshan River Xiaoshan,and the north of the west of the city is high,medium and low,mainly affected by water pollution and water surface ratio Impact of change.(3)Through the comparative analysis of water resources and water environment carrying capacity,the results show that changes in water environment carrying capacity can inhibit or promote the decline of water resources carrying capacity.When the water environment carrying capacity showed a downward trend from 2007 to 2010,the water resources carrying capacity When the water environment carrying capacity showed an upward trend from 2010 to 2015,the decline rate of water resource carrying capacity slowed down,and when the water environment carrying capacity accelerated from 2015 to 2017,the water resource carrying capacity showed a slight upward trend.The interannual fluctuation of water resources carrying capacity is small,and the interannual fluctuation of water environment carrying capacity is large,which is susceptible to human intervention.(4)Through comprehensive evaluation of the water resources and water environment carrying capacity of Hangzhou's core urban areas,it puts forward suggestions on the development of urban regional industries and proposed measures to improve the carrying capacity of water resources and water environment.