渚滑川河口拦门沙演变特性

Evolutionary characteristics of river mouth bar in the Shokotsu River

河口拦门沙的存在可导致径流流出不畅,并能引起一系列的河口生态及环境问题。特别是弯曲型河口,在波浪流、河川径流及弯道副流的共同作用下,拦门沙的形成及演变将更为复杂。通过对日本渚滑川河口多次实地调查资料的分析,揭示了渚滑川河口拦门沙的演变特性。结果表明:渚滑川河口修筑防波堤后,在东北方向的海洋入射波作用下,拦门沙由河口右岸发育并向左岸逐渐延伸扩展,其河水流动也相应由右岸偏向左岸一侧;不论河口有无拦门沙,3次洪水在右岸的最大冲深均稳定在-6m高程,且河床横剖面的形状基本不变,即汛期时该河口河床形状已达平衡状态。

The bar in a river mouth is formed depending on the balance between river dynamics and ocean dynamics, when the river channel curves in a river mouth, the bar maybe evolute most complexly due to channel s curvature. In this paper, by analyzing a great deal of data obtained in-site, the evolutionary characteristics of the Shokotsu River mouth bar were clarified as： （1） due to the coupling action of the bulwark built in the mouth of Shokotsu River and incident wave with the direction of north-east, a fiver mouth bar occurs in the fight bank originally, and gradually develops and extends toward left bank, accordingly the direction of the water flow varies from the right to left bank; （2） no matter river mouth bar exists or not, the elevation of the river bed keeps to a level of 6m after 3 ＇ times flood run out, that is, the bed form at the Shokotsu River mouth has been balanced between scouting and sediment in flood season.