历史时期人类活动对黄河下游河道变迁的影响

THE INFLUENCE OF THE HUMUN ACTIVITY ON THE DIVERSION OF THE LOWER REACHES OF HUANGHO IN THE HISTORIC PERIOD

历史时期黄河下游发生过多次变迁,人类活动是影响变迁的重要因素。本文就此对战争中的人为决堤,治河中的人工挽堵、筑堤以及中游地区的农垦等方面的影响作了探讨。

The lower reaches of the Huangho river changed its way several times in the historic period. There were many reasons. One important reason among them is the influence of human activity. The paper discussed it in the following four sections.1) The course diverted due to the artificial burst of the banks in the war;2) The course diverted due to the artificial blocking, in order to make the Huangho return to its original course or to lead it to a new one;3) The influence of building banks artificially. For instance,after banking up the river, the sediment deposition increased. It caused the bed level to be elevated over the adjacent area, making Huangho a 'hanging valley'.Another example is, the river pattern changed from branching to single way due to banking. Some lakes disappeard from this region caused by banking. 4) Agriculture and livestock husbandry developed alternately in the middle reaches of Huangho in the history.The condition of the forest vegetation and soil erosion, the relationship between burst in the lower reaches and the phenomena mentioned above in the middle reaches, is discussed briefly. The author concludes finally that the influence of the human activity mentioned above and the experiences from it should be remenbered not only in studying the history of Huangho diversion, but also in harnessing Huangho in the future. The author suggests that we should pay attention to the task in the middle reaches of Huangho while working in the lower reaches. Only by the conservation of soiland water and eliminating the sediment input from erosion in the middle reaches of Huangho, can there appear a new situation securely for a long time.