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In 2002, China launched the South-to-North Water Transfer Project after completing a 50-year feasibility study. By 2050, the three-route (i.e., East, Middle, and West) project will be capable of transferring 44.8 billion m3/year of water from the water rich Yangtze River to the arid north to alleviate water shortage and help secure a balanced social and economic development across the nation. However, diversion of such a large quantity of water could profoundly change the riverine environment of the upper Yellow River and the lower reach of the Han River, a tributary of the Yangtze River and the water supplying area of the project’s Middle Route, because of changes in the annual discharge. Secondary salinization seems inevitable in the water receiving areas of the North China Plain, and decrease in the discharge of the Yangtze River will result in seawater intrusion into the Yangtze Delta. This paper describes the project and discusses its environmental implications. Additionally, a long-term monitoring strategy under the umbrella of the Chinese Ecological Research Network is proposed for environmental monitoring. [ABSTRACT FROM AUTHOR]

The diverse hydro-climate between northern and southern China causes serious complications related to increasing food demand, declining water availability, and increasing flood risk in Changjiang and Yellow River basins. The huge projects of Three Gorges Dam (TGD) for diminishing flood and South-to-North Water Transfer Project (SNWTP) for driving water from Changjiang to Yellow and Hai Rivers to compensate for an imbalance of environmental resources will not necessarily solve all of the problems that they were originally intended to address. A sophisticated eco-hydrological model is required to evaluate the optimum amount of transferred water associated with these projects, together with socio-economic and environmental consequences. For this purpose, the process-based National Integrated Catchment-based Eco-hydrology (NICE) model was modified to couple with complex sub-systems in irrigation, stream junction, reservoir operation, and water transfer, to develop coupled human and natural systems and evaluate cause and effect of uneven water resources. The model clarified the impact of irrigation on eco-hydrological processes and predicted hydrologic change after TGD and SNWTP to estimate whether dilemmas between water stress, crop productivity, and ecosystem degradation would diminish. The result also showed the missing role of surface water - groundwater interactions and lateral subsurface flow, usually not considered important by assuming stationarity in previous researches of continental scales. A heterogeneous pattern of Time-Integrated Normalized Difference Vegetation Index gradient in agricultural fields helped to estimate uneven crop yield and its relation to water availability. This integrated approach will have some roles not only to re-consider this complex process from the view point of hydrologic and biogeochemical cycles, but also to clarify how the substantial pressures of complicated problems can be overcome by effective trans-boundary solutions. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A one-year study was carried out to investigate the seasonal fluxes and source variation of organic carbon transported by two major Chinese rivers, the Yellow River and Changjiang. In 2009, the Yellow River and Changjiang transported 3.20 × 1010g and 1.58 × 1012 g DOC and 3.89 × 1011g and 1.52 × 1012 g POC, respectively. The dominant input of the terrestrial organic matter occurred during the high discharge period from June to July for the Yellow River and from June to August for Changjiang, accounting for 36-44% of the DOC and 72-86% of the POC transported by the two rivers in 2009. The Yellow River transported much higher concentrations of inorganic carbon than organic carbon, while a reverse trend was found in the Changjiang, indicating the different sources of carbon discharged by the two rivers. Using radiocarbon and stable carbon isotope measurements, we identified the different sources and seasonal variations of organic carbon transported by the Yellow River and Changjiang. The Yellow River carried old POC with radiocarbon ages ranging from 4000 to 8000 years, while POC transported by Changjiang had a relatively younger 14C age ranging from 800 to 1060 years. The 14C ages of DOC were relatively younger (305-1570 years) and showed less variation between the two rivers. The seasonal variations found in 14C ages of DOC and POC indicate that a large fraction of recent-fixed labile organic carbon was transported by the two rivers in the spring and summer months. The different sources and seasonal variations in both fluxes and sources of organic carbon transported by the Yellow River and Changjiang could have an important influence on the biogeochemical cycle and ecosystems in the estuaries and adjacent coastal waters of the East China Sea. [ABSTRACT FROM AUTHOR]