Interaction Mechanism And Distributed Model Of Social Economy-Water-Ecology In The Shaying River Basin

Socioeconomic-water-ecosystem,which is consisted of socioeconomic,water and ecological subsystems,is a complex system.The subsystems are interrelated and muti-constrained.With the rapid human society development,the interaction between human and nature tends to be close.Simultaneously,the impact of human development on the natural ecosystem is becoming complex.In particular,the hydrological,water resources,ecological and environmental problems have become the key to restricting the harmonious development between human and nature in the highly human disturbed basins.However,in literature,the current research on the mechanism of social economy,water and ecology and the corresponding model developing,which consider solely the natural or social factors,have shown some limitations in dealing with the complex socioeconomic-water-ecosystem problems.Therefore,it is necessary to research the interaction mechanism of social economy,water and ecology from a system perspective and then forming the corresponding quantitative models.On the base of the team research and the literature,a quantitative method for assessing the impact of socioeconomic system on the river system is proposed.The proposed method is then applied to the Shaying River Basin for studying the interaction mechanism of social economy,water and ecology of the basin.According to the water cycle module of the SWAT model,a distributed socioeconomic–water-ecological model is developed by studying the coupling mechanism between the processes of natural and social water cycles,and the river water quality and ecological models.The model program has also been developed.By integrating with the harmonious regulation model,the proposed model is then applied to study the socioeconomic,water and ecological harmony regulation in the Shaying River Basin.The results contribute to the technical and methodological foundation for the integrated water resource management of the basin.The main research contents and conclusions are as follows:?1?Evolution characteristics of the main factors of the socioeconomic–water-ecosystem in the Shaying River Basin.According to the analysis of the concept and structural composition of the socioeconomic-water-ecosystem and the characteristics of the Shaying River Basin with multi-sluices and dams,high pollution and strong human activities,some representative indicators were selected from aspects of social economy,river and lake water system,hydrology,water quality and ecology.Some statistical and numerical methods were then selected to analyze the evolution characteristics of the socioeconomic-water-ecosystem.The results indicate that the Shaying River Basin has a rapid socioeconomic development recently.The flow rate shows a decreasing trend.Due to the effect of social economy,the concentration of water quality indicators fluctuated drastically,but there is no obvious decreasing trend.?2?Interaction mechanism of social economy,water and ecology in the Shaying River Basin.The interaction between two or three subsystems of social economy,water and ecology was analyzed firstly from a qualitative perspective in the Shaying River Basin.A quantitative method for studying the impact of socioeconomic system on the river system was then proposed by coupling the CCA method and the river water quality and ecological assessment method.The proposed method was applied to the Shaying River Basin for studying the impact of socioeconomic development on river water quantity,quality and ecology so that to reveal the interaction mechanism of social economy,water and ecology under complex environmental conditions.The results indicate that socio-economic development has an important effect on the basin's river environment and ecology.Taking water quality as an example,the influence degree,changing between 0.19 and 0.79 from 2000 to 2015,decreased slowly since 2010.The main influence factors are human density and sewage treatment rate.?3?The distributed socioeconomic-water-ecological model?SEWE?.According to the interaction mechanism of social economy,water and ecology,the distributed socioeconomic-water-ecological model?SEWE?was built by coupling the processes of water withdraw,water use,water consumption and drainage,the rainfall-runoff model and the river water quantity and quality models?the nonlinear relationship between water quantity,quality and ecology?from a system perspective of social economy,water and ecology.The SEWE model can perform an integrated simulation of the processes of hydrology,water withdraw,water use,water consumption,drainage,river water quality and ecology of the basin.The results indicate that the simulation accuracy of flow rate can be accepted with R²=0.78 and NSE=0.73 in the calibration period and R²=0.74 and NSE=0.70 in the validation period at the outlet section of the basin.The simulation accuracy of the water quality and ecological indicators can be accepted basically.However,the relative error of water quality and ecological indicators in some sampling sites of the basin are greater than 20%.?4?Application of the SEWE model in the harmonious regulation of social economy-water-ecology of the Shaying River Basin.In order to solve the mismatch between socioeconomic data and river water quality and ecological data,and the insufficient consideration of the interaction mechanism of social economy,water and ecology by the harmonious regulation model and the similar regulation methods in dealing with the harmonious problems between systems,a framework for studying the harmonious development of social economy,water and ecology was proposed by integrating the SEWE model and the harmonious regulation model.The results indicate that the harmonious development level of social economy,water and ecology is poor in the Shaying River Basin.The main influence factors are reginal GDP,the proportion of tertiary industry in GDP,the number of health beds per 10000 people,daily water consumption per capita,water consumption per mu of farmland irrigation,water consumption per 10000 of industrial added value,the quality of habitat environment,the concentrations of COD_Cr,COD_Mn,NH₄-N and TN contained in sewage water of industry,agriculture and household of the basin.