关键词: 三角洲, 废黄河口, 河口延伸, 苏北, 河口泥沙, 决口扇, 云梯, 海岸, 治河方略, 中值粒径

Abstract: The abandoned Yellow Eiver Delta was formed during 1194-1855, when the Kiver captured the Huaihe River, in Northern Jiangsn. It took 661 years to complete this process. In the early years, 1194-1495, only a part of discharge of Yellow Eiver flowed into Huaihe River, but a great quality of sediments deposited on the Huang-huai Plain. By then, the development of the abandoned delta was not so obvious, the river estuary was only 15 km long. Since 1495-1855, due to the changing of the old policy ’’ divert the flow to the south’’ into ’’ divert the discharge to the east to erode the silt", accelerated the silt deposition rapidly downstream, the delta building was quickened, its apex moved from Huaiyin to Ertao at the downstream of Yunntiguan. The extent of the delta was small yet the length of the estuary entended to 90 km.The develop model of the abandoned Yellow River delta was different from the present dalte. The old one was com posed of a number of parallel Subdeltas, forming a type of fan delta under the margin of Huaihe River fiord. These subdeltas were mainly take shape by the longititude deposition of sediments of the river, the lateral deposition of burst diversion of discharge and diffusion deposition by the shore. The present delta is formed by the frequency swinging of the River channel and numerous tonguelike deposition.Originally the Hongzehu lake was connected with the abandoned river. Before 1855, the fresh water of the lake played a role of adjustment by eroding the river channel. The back deposition of the estuary, generally, will not beyond Huaiyin. The raise of the river bed at downstream of the Yellow River was mainly due to the deposition along the river channel.