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Poyang Lake is the largest freshwater lake in China and is internationally recognized as an important lacustrine and wetland ecosystem with abundant biodiversity. Since 2003, the average la...

Overexploitation of water resources at middle reaches has threatened downstream oasis in arid inland river basins. To achieve sustainable development, ecological water conveyance is one effective measure to reallocate water resources between socio-economic and natural systems. A comprehensive impact assessment of ecological water conveyance on groundwater-dependent ecosystems that are common in downstream inland river basins is needed. The present study integrated the technologies of remote sensing analysis, trend detection, and numerical simulation into a technical framework that identifies the spatial response and temporal dynamics of vegetation to groundwater changes induced by ecological water conveyance. The Normalized Difference Vegetation Index (NDVI) was used as a proxy to estimate vegetation. The structure of the framework we used is clear and reasonable. We used remote-sensing data and ground truth information, and a decision tree that incorporates an iterative self-organizing data analysis technique. The decision tree classifies the land cover into affected and unaffected areas, and the results indicate the spatial range of impact. The Mann-Kendall algorithm and Sen's slope detect the tendency in NDVI series that indicates the temporal response of vegetation. The Verhulst logistic function, combined with environment carrying capacity function, constitutes a simplified vegetation dynamic model that can be used to predict potential impact through scenario analysis. An application in the Shiyang River basin in Northwest China evaluated the performance and usefulness of the framework; the accuracy of the results suggested that the framework is effective and practical. Additional case studies are required to assess the reliability and applicability of the framework and identify the factors that affect assessment results beyond our case study in the Shiyang River basin.

Water conservancy projects occupy an extremely important status in human development history. Human cognition about water conservancy projects has been in constant evolution along with the changing relationship between humans and nature (water). Based on a literature review, this study provides a systemic summary of the evolution of the human need for water resources and of water conservancy projects, as well as the equilibrium between humans and nature (river and lake ecosystems). More importantly, the transformation of cognition concerning the governance of nature and river and lake ecosystems is reviewed. Taking the perspective of modern rationalism on water conservancy projects, four major changes in human cognition are identified. Further, the most salient water-related issues arising from China&rsquo, s largest freshwater lake, Poyang Lake, are analyzed and the history and predicament of its governance are described. This is accompanied by a discussion on the countermeasures. Finally, based on the evolution of the human&ndash, water relationship and cognitive transformation concerning water conservancy projects, several suggestions are proposed for the planned construction of the Poyang Lake Hydraulic Project. The conclusions of this paper shed new light on the principles of water governance and water conservancy project construction in a new era that has witnessed a growing conflict between socioeconomic development and the water environment. Our suggestions are also valuable for the governance of Poyang Lake.

With the continuous growth of economic water consumption in arid regions, many endorheic rivers and terminal lakes have desiccated. As an important ecological engineering measure, water transport in arid regions has vital ecological significance for protecting the regional ecological environment and delaying desertification. In this study, Qingtu Lake, the terminal lake of Shiyang River, was selected to analyze the ecological effects of water transport by means of remote sensing interpretations and current year field investigations. The results demonstrated that, in July 2018, the water surface had formed and recovered to 5.68 km2. Additionally, Qingtu Lake formed a spatial gradient distribution in groundwater depth. The depth increased in gradient from the waterside to the desert edge. There was a significant increase in the overall regional vegetation coverage, which mainly occurred in the water areas because of the extensive growth in Phragmites australis, which reached 10.54 km2 in area in 2018. Furthermore, the regional vegetation formed a gradient distribution, which transitioned from hygrophytes to xerophytes. This study can provide guidelines for the protection and restoration of lakes in arid regions.