北仑河口潮汐汊道稳定性的环境影响因素分析

在自然条件和人类活动的双重影响下,处于中越之间的北仑河口潮汐汊道稳定性问题备受关注。本文基于历史资料与最新的调查结果,分析总结了影响河口潮汐汊道的各类环境因素。自然因素方面,汛期暴雨洪水及其携带的泥沙对塑造河口潮汐通道以及地貌形态起到重要作用;多次调查结果显示,非暴雨时期河口的含沙量较小,潮流动力不强,余流流速不超过10 cm/s;平水期和丰水期的常浪向以及强浪向均为南向波浪,对河口中国一侧浅滩有不利影响;风暴潮增水有利于河口西侧淤积、东侧侵蚀。人为干扰方面,由于越南一方大量开展水利、围垦、造堤连岛等工程建设,局部改变了河口水流流向,尤其是在竹山港西面,主航道深水线偏向中国一侧,这种情况短期内已无法扭转;来水来沙减少、人工采砂以及红树林滥砍滥伐加剧了中国一侧河槽、岸滩侵蚀。维护北仑河口潮汐汊道的稳定性是中越两国合作共赢的共同选择。

Analysis of Environmental Factors Affecting the Stability of Tidal Inlet in Beilun Estuary

Under the dual influence of natural conditions and human activities, the stability of the tidal inlets in the Beilun Estuary between China and Vietnam has received much attention. Based on the historical data and the latest results of survey, various environmental factors affecting the tidal inlets of the estuary were analyzed and summarized in this paper. In terms of natural factors, rainstorm, flood and sediment carried by them played an important role in shaping the tidal inlets and geomorphology of the estuary. The results of many surveys show that the sediment concentration in the estuary during the non-storm period is small, the dynamic of tidal current is not strong, and the velocity of residual current does not exceed 10 cm/s. The direction of normal wave and strong wave are both southward waves during normal season and wet season, which have adverse effects on the shoals of our side of the estuary. Storm surge is beneficial to the deposition on the west side of the estuary and erosion on the east side of the estuary. In terms of human disturbance, due to the construction of a large number of water conservancy projects, reclamation projects, dyke building and island linking projects on the Vietnamese side, the current direction of the estuary has been partially changed, especially in the west of Zhushan Port, the deep waterline of the main waterway is biased towards China, which cannot be reversed in a short time. Meanwhile, the erosion of river channel and beach on our side is aggravated by the decrease of incoming water and sand, artificial sand mining and mangrove deforestation. Maintaining the stability of the tidal inlet at Beilun Estuary is a common choice for win-win cooperation between China and Vietnam.