长江河口横沙东滩自然演变及工程影响

Natural evolvement and effect of project in the Hengsha East Shoal of the Changjiang River estuarine

横沙东滩(含横沙浅滩)是长江河口主要浅滩之一,在浅滩两侧(北港和北槽主槽)水流控制下,受浅滩横比降形成的过滩水流和较强的风浪作用影响,滩面长期以来少有淤涨。通过对1995～2002年的地形资料(吴淞基面)进行研究分析表明:从总体上看随着北港主槽向南岸进逼,造成横沙东滩窜沟西部到白条子沙之间的滩区北沿明显内凹;随着长江口深水航道治理双导堤工程的实施,在北导堤产生的堵汊、导流和拦沙的作用下,白条子沙至横沙东滩沟滩面出现微淤;而横沙东滩窜沟以东滩面难以淤高。采用促淤工程和就近吹泥上滩方式,增加横沙东滩的滩面高程以加快造地,从而达到既疏浚航道又增加湿地面积的双赢效果。

The Hengsha East Shoal including the Hengsha shallow shoals is one of the most important shallow shoals for the Changjiang River estuarineUnder effect of strong wave and the current over the shoal due to transversal water level gradient, the Hengsha East Shoal didn't deposit dramatically from long time agoBased on the topographic maps dated from 1995 to 2002, the paper mainly deals with the evolution of the Hengsha East ShoalThe results show: the condition of water and sediment changed due to the construction of Deep Channel Project for a long period of timeThe shallow shoal from Baitiaozi shoal to the Hengsha Channel deposited slightly because of these changesThere is little deposition on the tidalflat in the east of Hengsha East Shoal Channel because of the strong currents along the north dam and waves before the projectWith the Deep Channel Project continuation and blowing the sediment which was dredged form the main channel into the Hengsha East Shoal, the effect of project will become more prominent