Numerical Simulation On Flood In Downstream Of Weihe River And Countermeasure Study On Controlling Flood And Decreasing Calamities

The Yellow River is much more affected by human action than other rivers. Since the construction and use of San Men Gorge reservoir, the conditions of water and sediment and evolvement laws of riverbed of lower reaches of Weihe River had taken place greatly. The lower reaches had changed from the river of the balance of scour and sediment to that filled up strongly, from that not fortified to fortified, from save and affluence to calamities frequently, and became the typical example of the lower reaches of the Yellow River. The mission of flood control is very huge. Since Wei He River locates at the accordant junction area of the Yellow River, Luo He River, Jin He River, Wei He River and other tributaries in South Mountains, the problems of water and sediment are very complex, and so the flood control and treatment of the river are rather complicated, formidable and perennial and integrative treatments have to be taken for the whole drainage area.The main problems in the lower reaches of Weihe River are as following: filling up of sediment seriously, rising of riverbed and continuously development of overground suspended river, shrinking of main riveway, weakening of flood discharge, slowness of flood advancement, much higher of water level under the same flux, receding of flood control standard, inverse gradient ratio of riverbeds of tributaries in Er Hua South Mountain, aging of projects for flood control and discharge, easily breaking of bad quality banks, seriously insufficiencies of capacity of discharging accumulated water in flood control areas, decreasing and turnoff of main waterway and deterioration of environment. The main waterway of Weihe river can be visually described as "there is no water in upper reach, contaminated in middle reach, filled up seriously in lower reach". Considering these problems, numerical simulation and prediction had been taken for water march of flood progresses in 1954 and 1981, respectively one time for 100 years and 50 years and provided theories for making decisions and treatment of the lower reach of Weihe river. On these basis, research on the integrate treatment of lower reach of Weihe river should take the large drainage areas of the Yellow River and Weihe river into account for different complicated factors according to the author's experience of working on flood control, project construction and management from the point of view of drainage areas, and so solves these questions ultimately. And some countermeasures were put forward for flood control systems, integrate treatment and using of resources as followings "blocking in upper reach, discharging in lower reach and leading and enforcement in middle reach.The paper aimed at providing instruction for making decisions for flood control in lower reach, treatment and layouts, research in the prophase and project construction for flood control and management.