| In the late 1980s, the sediment yields diffused to the Gudong sea area decrease drastically with the Yellow River estuary extending to the east, which make the sea area become a serious eroded area. Though the Yellow River changes the estuary to the Qing 8, as a result of low water and few sands in successive years and a lot of oil fields in GuDong, coastal line backs off seriously. In 1999, the Xiaolangdi Reservoir was put into use. The characteristic of water and sediment in the estuary area changes remarkably as a result of 6 times regulating water-sediment from the 2002. According to the characteristics of the incoming water and sediment affected by the Xiaolangdi reservoir, and considering the new case that Yellow River changes its main channel to the Beicha river, this will be important scientific significance for analyzing the sediment transport and the evolvement of the shoal, predicting the tidal current changes with time and space, improving the present erosion status for Gudong bank.Based on analyzing wind field in the estuary and the ocean hydrodynamic condition, this paper used the Surfer Water Model System (SMS), set up a two-dimensional triangular (three -corner and three-mid side nodes) elements model for simulating the Yellow River Estuary and the extension sea area around it, and verified the calculating results by actual material, proved the SMS is of capable of simulating and forecasting the flow fields, tide level, and sediment transport and coastal shoal evolvement of Yellow River Delta Area.This paper gets the following conclusions by calculating the checked model that has been used to simulate the tidal current and the sediment transport in the case that the Yellow River estuary alter to the Beicha river.The calculating data show new characteristics for sediment transportation as a result of changing ocean dynamic condition and terrain in condition that Yellow River estuary changes to the Beicha river. The range of the sediment transported into sea become narrow in vertical seacoast and widen along the seacoast which is consistent of the reciprocating tidal current ellipse character. At the same time, the sediment will accumulate to both sides of the estuary and the attenuation isn't symmetry affected by Criolis'force and tidal current.According to the water and sediment condition and estuary position in recent years, the Dongying harbor will be not filled up in the early stage. Because new estuary is affected by the ocean hydrodynamic condition and the Criolis'force with the passage of time, it will extend to ENE in the early stage and then turn to southeast, this mouth will be away from the harbor and the effects aroused by the sand will be getting smaller.The route changed into Beicha river will flow into sea from the south of the Gudong sea wall; sediment diffuseness will affect the oil field directly. Averagely, the Gudong bay will be filled up between 3-18cm per year, and it will be strengthened with the sand quantity increase after the 2002. It will improve the sea wall scouring status, increasing the security of the Gudong bank. At the same time, the estuary will push out and creating a large area of land in near future which can make the oil exploits on land instead of in the sea.Some suggestions are obtained in the end of this paper. That is said it is necessary to master the rule of the estuary evolvement based on improving the forecast of flow and sediment, strengthening the observation of estuary channel process and ocean dynamic and research scientifically, First of all, it should make sure that changing the estuary does not affect an influence on the route and fixed number of year of channel. Also, the time of changing the estuary route scientifically must consider both the oil field development and its exploitation in beach area.
|
PDF Full Text Request