Study on the Role of Tidal Currents in the Process of Formation and Development of the Changjiang River Delta

摘要

The Changing River Delta is a delta of tremendous scale which is formed under the control of tide and tidal currents. The study on the role of tide and tidal currents in the process of formation and development of the Changing River Delta can provide a typical example for the oceancontinent interaction process in the east area of our country. The tide and tidal currents in the Bohain Sea, Yellow Sea and East China Sea at the post-glacial transgression maximum are simulated, the sediment transport field in the Paleo-Changjiang River Estuary (PCRE) and its peripheral area at that time is calculated, and the seabed erosion/accretion pattern is obtained according to the divergence of sediment transport rate. The results show that a distinctive wave belly of standing tidal wave existed at the post-glacial transgression maximum and the wave belly lines protruded seawards from the wave belly point in the mouth of the PCRE. Under the wave belly control tidal currents coverage to or diverge from the wave belly point. After a single tidal cycle, sediments started by tidal currents are mainly transported into the PCRE in the southeast and east directions, while there is a small amount of sediment to be nettle transported to the northeast-soiluthwest area off northern Jiangsu coast. The above sediment transport certainly results in deposition within the PYRE, in the area to the northeast of PCRE, and in the nearshore area between the south bank of the PCRE and the northern one of the Qiantangjiang River Estuary, while erosion occurs in the areas to the east and southeast of PCRE.