"Second Hangs The River" Prevented Flood To The Low Reaches Of The Yellow River Influence And The Countermeasure

The Yellow River is the second great river of our country with a long history. It has the inherent development law, and at the same time because of the change of natural environment and the influence of human activity, the new situation appears , it will creats new problems. The " second hangs the river " at the down stream of the Yellow River is a new problem under the new situation. Near these decades, because of the influence of human activity, the situation of the water and sand in the Yellow River has change a lot, overflow beach opportunity in the down stream reduces , in the main channel it is accelerate to deposit, cause the main channel higher than the beach of two sides, and the beach of two sides is higher than the ground outsind the Yellow River embankment, so it forms the " second hangs the river ", it leads to the serious influence to the preventing of flood in the down stream of the Yellow River.In order to probe the forming mechanism of " second hangs the river " , analyse its endangering and development trend, seek effective measures. At first in this text we summarize the current studying situation of the " second hang the river " both inside and outsinde our coutry, analyse the characteristics and preventing flood situation at the downstream of the Yellow River. Secondly, on the basis of making a concrete analysis of development course and existing problem of the " second hangs the river ", analyse the origin cause of formation, find that the change of the water and sand terms in the downstream, and the reduce of great flood opportunity are the basic reason, the channel controling projects and production bank construction , prosperity in the beach and the great scale utilizes are important reasons to form the " second hangs the river ". Finally, aim at the reason of the " second hang river ", combine the river characteristics at the downstream of the Yellow River, discuss the control countermeasure , propose that " reduce sand and increase water " can solve the " second hangs the river " problem fundamentally, the improve of wide river border overall arrangement at the down stream can slow down the state of " second hangs the river " too, put forward the view that the control of " second hang river " should combine the river channel control and the beach conrol together .Regard the contoling countermeasure as foundation , combine the forming reason of the " second hang river " , propose the administration measure: Standardized dyke engineering construction, transfer the water and in good time, silt the beach and clusters of ditch, silt and fill out the river and dyke, dredge the main channel, build safety devices in the beach district and reinforce the management of the production bank construction, forbid planting high pole plant ,and other non-engineering measues within the range of river, and bring the use and management of beach district into the administration measure of " second hangs the river".On the basis of above-mentioned research, this text makes the section of the south light dyke to Penglou whose " second hang river " is the most serious for the project instance, through administration measures like dredging up the main channel, silt clusters of ditch , fill out dyke and river ,etc. having proved its feasibility and practicability. Through managing, in this section ,this main area of trough is expanded , the ability of passing flood increases, and at the same time, the average bed high of the main river reduces , which alleviates the situation of " second hangs the river " in this section. The implementation of the experimental project has reduced the possibility of " great calamity of little water " to a certain extent, has lightened the threat of flood to people of beach district, and has improved the traffic condition of the beach district and ecological environment.