Disilting Analysis For The Regulating Reservoir Of Wanjiazhai Yellow River Diversion Project Connection Works

The sedimentation of the reservoir is a general existing problem for the rivers rich in sand and the appearance of the problem is also extremely complex. The Fen 1 Reservoir, as the short term regulating reservoir of SM Connection Works, also has the sedimentation problem. With the increasing sedimentation and the useful storage decreasing, the reservoir is losing the ability of regulating and a new reservoir will be needed to build upstream the river. In this case, in order to determine the operation mode of the reservoir in flood season, the joint operation of Fen 1, Fen 2 and Haoshuigou reservoir, the density flow desilting rule and the control mode of the Fen 1 reservoir, we analyze the disilting for the regulating reservoir of Wanjiazhai Yellow River Diversion Project Connection Works.The analysis adopts a model entitled "the Model of Silt Souring for River and Reservoir " , calculates the model and parameters and establishes the model of disilting the regulating reservoir basedupon the data in 1967. We also analyze the density flow desilting of Fen 1 reservoir in accordance with the data from July 6 to 7, 1977 and the partial data from Guanting reservoir.According to the calculation, the sedimentation feature of the Fen 1 reservoir is the triangle, the Fen 2 reservoir is taper and the Haoshuigou is strap.We also got the results about operation mode of the reservoir as follows: the dead storage in flood season should be 6m higher than the sedimentation elevation and 4m higher in the non-flood season. By 2002, the dead storage in flood season should not less than elevation 1122m.In order to avoid making the Fen 1 reservoir to be a muddy water reservoir, the Fen 1, Fen 2 and Haoshuigou reservoir should be jointly controlled and operated. While the reservoir can discharge large amount of the silt, it can meet the requirement of the urban and industrial supply, bring light effect to the agriculture water supply, and alleviate the sedimentation of the Fen 1 reservior and prolong the life circle of the reservoir. This analysis established a mathematic model of disilting calculation of Fen 1 reservoir, provided a reference model for the major and middle size reservoir in Fen river basin, analyzed the density disilting of the Fen 1 reservoir in flood season, raised a model of three dimension reservoirs joint operation, reduced the sedimentation of the Fenl reservoir and provided a base for the future control.The analysis is very important for the Yellow River DiversionProject as it gives the sedimentation feature and operation model of SM regulating reservoir, which is significant for alleviating the sedimentation of Fen 1 reservoir, prolonging the life circle of the reservoir and assuring the quality of the yellow river water. The mathematic model of disilting and desity disilting rule has practical significance and provides reference and experience for the future calculation with similar situation in Fen river basin.