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Accurate river runoff simulation is of great importance for basin hydrological simulation, water resources plan and sustainable management, hydrological disaster prevention and control. With the rapid development of the earth observation satellite remote sensing techniques, microwave remote sensing monitoring can provide a new method for river runoff simulation. To date, for river runoff simulation, further exploration is needed based on passive microwave remote sensing brightness temperature observations. This paper applied the M/ C signal method to river runoff simulation in typical river basins in China based on a high-resolution passive microwave remote sensing brightness temperature dataset. The usability of this method was discussed. To analyze the influence factors of the simulation results, 7 geomorphologic and hydrometeorological factors were chosen, including river width, mean observed discharge, control area, vegetation percentage, elevation, land use / cover and climate type. Results of the monthly runoff simulation show that among the 61 typical sites in 7 river basins in China, R² of 59. 0% of them exceeded 0. 5 and more than 41. 0% reached an ENS larger than 0. 5. Performance for the sites in basins of the rivers in Southwest China is obviously better, especially for the sites on the Tibetan Plateau; elevation, mean observed discharge, climate type and width of the river cross section are found out to be the dominated factors; and the M/ C method is more suitable for sites on small rivers of high elevation under mountain plateau climate. Generally, this paper can inspire research ideas for river runoff simulation, thus providing reliable guidance for extending the hydrological application of microwave remote sensing in China. [ABSTRACT FROM AUTHOR]

Climate change and human development have significantly altered the processes of natural water cycling, aggravating the challenge of worldwide water governance. China has initiated a new paradigm of water governance. However, the gap between concept and reality widened due to a lack of appropriate data and methodology. Current water management focuses on limiting the water withdrawals and improving the water use efficiency, and is not yet able to ensure the implementation of the new water governance paradigm. After a thorough study of the advanced development and achievement of water governance policies both at home and abroad, the conclusion has been reached that the total water consumption should be introduced as an additional management indicator to implement a dual control of water withdrawal and consumption. The paper proposes to: (1)Establish water consumption monitoring infrastructure with evapotranspiration remote sensing monitoring as its core component. (2) Implement the rigid water resources constraint by determining available water consumption targets of human activities in the basin, considering water requirements of environmental flow and ecosystem restoration, and establish a cascading system assigning targets to the sectors and/or stakeholders. (3) Implement the water consumption reduction schemes by limiting agricultural planting areas and optimizing ecosystem restoration with indigenous species. It is expected that the proposed approaches will effectively ensure the implementation of China′s new water resources governance paradigm with innovative data, methods, and measures. [ABSTRACT FROM AUTHOR]

The macro-tidal estuary with a mountain stream is a typical estuary on China′s southeast coast, characterized by intense dynamic forces, active sediment movements, and a robust response to human activities. It demands further investigation of its evolution mechanism under both natural conditions and anthropogenic stresses. This paper takes the Jiangxinyu reach of the Oujiang River estuary as a case example to explore the river′s evolution under the influence of human activities, including effects of longitudinal dam construction, sand mining, and shoreline adjustment since the 1970s. Measured data analysis and a two- dimensional flow and sediment mathematical model were used. The results confirm that anthropogenic stresses have altered the natural periodic alternation of the river′s main and side branches. Moreover, the undercutting of the riverbed caused by sand mining from the beginning of this century has increased tidal range by 0. 5 m and tidal prism by 47%, while weakening the discharge asymmetry and sediment transport asymmetry indices by 0. 08—0. 30 and 0. 28—0. 54, respectively. The undercutting of the riverbed has also weakened the ebb and flood asymmetry. These conditions have subsequently helped slow down the shrinkage of the side branch. The evolution mechanism is dominated by both natural and human activities. Overall, the research findings may be a reference for river evolution and protection under the influence of human activities. [ABSTRACT FROM AUTHOR]

Water security is an integrated concept of multiple dimensions, including water resource utilization, water eco-environmental protection, water disaster prevention among others. In this paper, an evaluation indicator system of water security are constructed, focusing on five dimensions: water quantity, water quality, sustainability, affordability, and flood security. It is based on a summary and discussion of the definition, connotation, and evaluation of water security dimensions. We provide increased understanding of applicability and usefulness of water security evaluation systems, thereby avoiding content duplication or overlaps between different dimensions and promoting the accuracy of problem diagnosis. In doing so, we used a multi-expert decision-making method to quantify indicators weight and to standardize data. Compared with evaluating the water quantity security using indicators of water resources endowment alone, this evaluation system implies concepts of water demand and sustainable security that included in resource security, which is capable of analyzing actual reasons for water shortage. Affordability, which is seldom considered in previous studies, is supplemented to ensure system integrity of water security assessment. Finally, a case study of water security evaluation of China is carried out with cluster analysis. The main water security problems in each region of China were diagnosed well, which are in line with the current situation of China. This test indicates that the evaluation system is both reliable and practically applicable. [ABSTRACT FROM AUTHOR]