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Abstract The quantitative assessment of the impact of socioeconomic development on river water environment is important to the scientific management of river basins. However, current methods have high data requirements or are difficult to deal with the impact between systems (which is defined by a collection of indicators). This paper first uses canonical correlation analysis (CCA) to understand the relationship between socialeconomic system (defined by a set of indicators reflecting socioeconomic development) and river system (defined by a set of indicators reflecting river water environment), and then proposes a method to assess the impact of socioeconomic system on river system by integrating CCA and the degrees of influence of river system indicators. The proposed method and framework are applied to the Shaying River Basin with the characteristics of multi-sluices, high pollution, and dense population based on data from 2000 to 2015. Results indicate that socioeconomic and river systems are highly related to each other with the average influence degree of greater than 0.9, indicating very close relationships between socioeconomic and river systems. The changes of influence degree vary between 0.19 and 0.79 with a turning point in 2010. Most of the influence levels are "moderate" (influence degree between 0.4 and 0.6) or "high" (influence degrees between 0.6 and 0.8) before 2010 but become to "low" (influence degrees between 0.2 and 0.4) since then. In addition, the influence degree shows a significant increase from upstream to downstream with Zhoukou Station as the turning point, meaning that the stronger the human activity is, the greater the impact of the socioeconomic system on the river system is. The main influential factors are population density and sewage treatment rate. The proposed method contributes to the research in river management with limited data availability and the results can serve as an important reference for basin management. Graphical abstract Unlabelled Image Highlights • A new method of river system impact assessment was proposed. • The impact of socio-economic development on the Shaying River Basin was assessed. • The CCA method was explored for assessing socio-economic impact of river system. • The key influential factors were identified for management purposes. [ABSTRACT FROM AUTHOR]

In order to study river health status from harmonic relationship between human and natural environment, a river health evaluation method was proposed from the aspects of ecosystem integrity and human service demand, and the understanding of river health connotation. The proposed method is based on the harmony theory and two types of river health assessment methods (the forecasting model and index evaluation). A new framework for assessing river water health was then formed from the perspective of harmony and dynamic evolution between human service demand and river ecosystem integrity. As a case study, the method and framework were applied to the Shaying River Basin, a tributary of the most polluted Huaihe River Basin in China. The health status of the river's ecosystem and its effect on the mainstream of Huaihe River were evaluated based on water ecological experiment. The results indicated that: (1) the water ecological environment in Shaying River was generally poor and showed a gradual changing pattern along the river. The river health levels were generally “medium” in the upstream but mostly “sub-disease” in the midstream and downstream, indicating that the water pollution in Shaying River were mainly concentrated in the midstream and downstream; (2) the water pollution of Shaying River had great influence on the ecosystem of Huaihe River, and the main influencing factors were TN, followed by TP and COD Mn ; (3) the natural attribute of river was transferring toward to the direction of socialization due to the increasing human activities. The stronger the human activity intervention is, the faster the transfer will be and the more river's attributes will match with human service demand. The proposed framework contributes to the research in water ecology and environment management, and the research results can serve as an important reference for basin management in Shaying River and Huaihe River. [ABSTRACT FROM AUTHOR]

• River water quality and ecology were investigated in dam dominated basin. • A framework was formed to assess impact of human activity on river water quality and ecology. • A significant seasonality of water quality was revealed with higher impact in winter than in summer. • Seasonality of the impact was weakened as human activity increased. • Seasonality of water ecology was almost not significant in our study. Improving water quality and ecological status is an important foundation for sustainability development. Increasing human activity and the corresponding land use change lead to the deterioration of river water quality (WQ) and water ecology (WE), but the pathway is complex, especially in dam dominated basins with the altered streamflow by the joint regulation of multiple dams and sluices that leads to changes in WQ seasonally. However, the research on this issue is inadequate and it is urgently needed since a large number of dams and sluices have been built worldwide for socioeconomic benefits, putting the basin's WQ and WE under pressure. Based on water ecological experiment, a framework was proposed to assess the impact of land use (LU) and urbanization on WQ and WE in different scenarios derived from human activities (low, and intense) and seasonality (winter, and summer) in a dam dominated basin. The framework was applied to the Shaying River Basin located in the Central China as a case study. The remote sensing of Landsat 8 OLI_TIRS images and Geographic Information System (GIS) were combined by using the support vector machine classification method to extract the land use patterns and to map the spatial distribution diagrams of WQ and WE indicators based on in-situ experimental data. A canonical correlation analysis method and Pearson correlation testing were adopted to evaluate the impact of LU and urbanization on WQ and WE in the basin. Results showed that LU and urbanization had a great impact on WE compared to WQ due to the slow reaction of ecosystem in the basin. Because the former was resulted by long-term regulation of dams and sluices, and the latter was related to the short-term changes of river environment. Moreover, the former was attributed to the latter largely. LU and urbanization impact on WQ had a significant seasonality with higher impact in winter than in summer, and the seasonality of the impact was weakened as the disturbance of LU and urbanization increased. The seasonal variation of WE indicators was almost not significant in our study due to their adaptability to surrounding environment. Our results provide insights to water resources management and ecological restoration in the Shaying River Basin and other similar basins with intensive dams and sluices. [ABSTRACT FROM AUTHOR]