关键词: 潮间带, 淤积速率, 滩面稳定性, 长江口

Abstract:

Based on the data, which were obtained weekly at 24 sites along a transection set up in the Eastern Shore of Nanhui from Apr 1999 to Apr. 2000, this article quantificationally examines the cross shore differences of annual vertical accretion rate, absolute and relative stabilities of sediment surface. The results are as follows: (1) The annual vertical accretion rates are distinctly different at each site along the transection with a maximum of 49.5 cm/a at the site where the submergence probability is about 30% (between the average neap high water level and the average high water level) and a minimum of 2.2cm/a at the site near the seawall. The maximum is 22 times of the minimum. The annual vertical accretion rate is comparatively low where the marsh and the bare flat meets. Totally, the annual vertical accretion rates are lower at sites on the bare flat than those at sites on the marsh. (2) The absolute stabilities of the sediment surface are different at each site along the transection. Because it indicates the same phenomenon as the annual vertical accretion rate does, the difference of absolute stability is in accordance with the difference of the annual vertical accretion rate along the trasection. (3) The relative stabilities of the sediment surface are different at each site along the transection. The relative stabilities are much stronger at sites on the marsh than those at sites on the bare flat. (4) Vegetation plays an important role in protecting the shore from erosion and stimulating accretion It also enhances the relative stability of sediment surface The difference in short term evolution of intertidal muddy flat is a compositive reflection of the submergence probability, energy of the wave and tide as well as the distribution of vegetation along the transection

Key words: intertidal zone, accretion rate, stability of sediment surface, Yangtze River estuary