Coupling Analysis Of Urbanization And Water Environment In The Huaihe River Basin,China

An a link between river source and estuary,river basin is not only a hydrological unit with integrated,independent and self-formed system,but also an important regional unit of organization and management of regional and national economic with exploitation and utilization of resource system.The Huaihe River was the first hydrological unit where water pollution was prevented from a view of river basin in China.As one of the seven largest rivers,pollution in the Huaihe River basin became more and more severe with fast development of economic and accelerating of urbanization process since the 1980s.In the context of open-up in the eastern and rising of central China,as a link between the eastern Longhai region and central China economic area,the rate of urbanization in the Huaihe River basin will exceed average national rate.The fast increase of population and rapid development of economic will bring great pressure on the improvement of water quality,and meanwhile,the South-to-North Water Transfer East Line Project needs higher water quality.As a opening and complicated system,the urbanization and water environment in the river basin exists an interacting and coupling relationship.On one hand,the accelerating of urbanization process certainly causes the change of water environment in the river basin,and such change is characteristic by the worsen of water environment in the early time but by the improvement of water environment in the middle and later time.On the other hand,changes of water environment may result in changes of the quality and rate of urbanization process in the river basin,wherein the improvement of water environment is favorable to rising of quality and rate of urbanization process,and the worsening of water environment can restrict the urbanization process.Therefore,it is necessary to study on the coupling and coordination relationship between urbanization and water environment in the Huaihe River basin.In this study,the conception of coupling relationship between urbanization and water environment was analyzed based on the summary on its research at home and abroad.The stress effects of urbanization on the water environment and restraint effect of water environment on urbanization was explored from three aspects including population urbanization,economic urbanization and space urbanization.And then,such coupling relationship between urbanization and water environment in the Huaihe River basin was examined using the Complex Theory from the view of self-organization theory,synergetic theory,theory of dissipative structure and systemic dynamic.Based on the analysis on the on changes of urbanization and water environment in the Huaihe River basin,change phases of urbanization and the construction area in the Huaihe River basin was analyzed.The upper and middle reaches in the Huaihe River basin were divided into the sub-basin,and the relationship between eco-society development and water pollution was discussed by the method of correlation analysis and linear regression mode.Additionally,spatial and temporal changes of water quality in the Huaihe River basin during the period of fast urbanization process were investigated by the methods of mathematical statistics and wavelet analysis.The evaluating indicators of urbanization quality were constructed to measure the urbanization quality in the Huaihe River basin according to the connotation of quality of urbanization.The mode of coupling and coordination measurement between urbanization and water environment was established to evaluate their coupling relationship in the Huaihe River baisn,and spatial distribution of coupling and coordination measurement in different cities in the river basin was studied by the method of exploratory spatial data analysis.And main conclusions in this study can be attained as follows.In general,the urbanization level in the Huaihe River basin was low and belonged to fast development phase in the middle of urbanization process.The construction area in the municipal district of the Huaihe River basin increased by 1522.94km2 in 2000-2010,and temporal changes of construction area show phase changes.In the study period,the rate index and amplitude index of construction area in the Huaihe River basin was 12.25%and 0.52.The difference of the rate index and amplitude index of construction area in different cities was obvious.And the concentration of the scale of land use for city construction in the high rank cities in the Huaihe River basin was not obvious.The middle and low rank cities were dominate in the Huaihe River basin.The distribution of land use for city construction was even.The value of divided dimension of the land use for city construction show increasing trend in the Huaihe River basin,indicating that difference between city systems in the Huaihe River basin decreased along with time going on with increasing equilibrium degree of land use for city construction.Furthermore,medium scale of cities was dominate in the Huaihe River basin,and medium and small cities evolved toward big and medium type respectively.There are periodic variations for CODMn,DO,NH3 and pH contained in the river at multiple scales,including seasonal scale(0.25-0.5a),annual scale(?1.0a)and inter-annual scale(2-5a).And the periodic variation at annual scale(-1.0a)was significant.The periodic variation of water quality in the Huaihe River was influenced by basin precipitation and riverine discharge.And the signal of periodic variation became weak due to the strong disturbance of human activities.The long-term trend of water quality in the Huaihe River basin was depended on the combined impacts of human activities during the process of urbanization in the Huaihe River basin.The urbanization quality in the Huaihe river basin was generally low.The difference of evaluated result of urbanization quality in different cities was significant,and the highest score of urbanization quality was more 2.46 times than the lowest score.Citied with higher score of urbanization quality was the provincial capital and these cities with good development base in the lower reaches,including Zhenzhou,Hefei,Yangzhou and Zibo cities.And the urbanization quality in the middle area of river basin was relatively low.Additionally,the structure of urbanization quality in the Huaihe River basin was uneven,and the values of development level of green urbanization reflecting sustainable development of urbanization was the highest,however that of harmonious urbanization was relatively lower.In the Huaihe River basin,the urbanization and eco-environment system is in the antagonistic stage,and the development pattern of urbanization belonged to extensive mode,which put great negative effects on the water environment.There is significance integrated coherence and synergistic effect between urbanization and eco-environment construction in the Huai River Basin in the study period,indicating low coordination coupling stage.The significant difference of coupling and coordination degree existed among different cities in the Huaihe River basin.The cities with similar coupling degree tended to concentrate in the river basin,and there are negati've spatial self-correlation for the coordination degree of different cities.