Water Environmental Problems Associated with Natural Processes and Human Activities in the Lower Reach of the Yellow River

摘要

Human activity has a stronger impact on environment at modern stage than ever before, and many problems have occurred in the lower reach of the Yellow River, which is fragile in ecological conditions. Though it is difficult to differentiate human activity from natural processes, such as climate and land cover change since both of them are well integrated at the modern stage, it is worth identifying the main cause for a specific problem in order to put forward an appropriate countermeasure. Human activity was diagnosed as the reason for drying up in the Yellow River, while groundwater flow system was found to be the cause for widely distribution of salinized. land and the existence of nitrate in the shallow layer of aquifer. On the other hand, water diversion in the middle and lower reaches of the Yellow River since 1970s affected geochemical characteristic along the groundwater flow system by accelerating water balance and circulation.