长江口北港分流通道近期演变及治理措施

Recent evolution and regulation of distributary channel of Beigang in Yangtze River estuary

南、北港分流口河段是长江口河势演变最为复杂、最为动荡的河段,也是长江口河势演变的控制性河段,而该河段演变的重点又在于北港分流主通道的演变。依据该河段多年实测水下地形资料,对北港分流通道的历史和近期演变机理、趋势进行了探讨。分析认为,近期随着上下游河段一系列涉水工程的实施,明显抑制了历史上北港分流主通道"上提下移"的循环演变模式,但洪水以及扁担沙体的活动性,仍使北港分流主通道的稳定存在较大隐患。结合长江口综合整治规划,综合考虑河势、航道、水土资源利用等因素,进一步提出了稳定北港分流通道的治理设想。

The tributary reaches of Nangang and Beigang channels are the most complex and easily changed ones in Yangtze River estuary, and also the controlling reach in Yangtze River estuary. The evolution of the distrihutary channel of Beigang is the key in this reach. Based on the field data,the historical and recent evolution mechanism and trend of the distributary channel of Beigang is discussed. The resuh reveals that the previous evolution of moving up and down in the main passage channel is re- strained by a serious of engineering measures at upper and lower reach in recent years. The stability of the main passage channel of Beigang is threatened by the flood and activity of Biandan shoal. Based on the comprehensive planning of Yangtze River estuary （2004） , a new thought to stabilize the distributary channel of Bcigang is presented in consideration of the river regime, naviga- tion and utilization of the water and land resources.