Shandong Peninsula On The Lake Tidal Inlet Sediment Transport And Accumulation

Yuehu, known also as Swan Lake, lies in the southwestern part of Rongcheng Bay, eastern Shandong Peninsula. It covers an area of 4.94 km2. It is encircled by land in the west, north and south, and is separated from Rongcheng Bay by a sand spit in the east. In the southeast there is an entrance channel, 132 m wide, which connects the tidal basin with the open sea. The Yuehu tidal inlet system consists of an ebb delta, a flood delta, a tidal basin and a tidal channel at the entrance to the basin; it is a typical tidal inlet on sandy coast. We investigated the sediment characteristics, hydrodynainic conditions and geomorphological features of Yuehu extensively, from November to December, 1998 and from August to September, 1999. The results show that Yuehu is very shallow, with water depths of 0.5 to 1.5 mover most parts. The surficial sediment has a distinct distribution pattern: from the edge to the central part of the basin, sediment becomes progressively finer, from gravelly-sand, through muddy-sand and sandy-mud, to mud. A short core collected from the central part of Yuehu is composed of silt and clayey- silt; it is associated with an averaged water content of around 54.67 %, an averaged organic carbon content of around 2.7 %, a deposition rate measured by 2t0Pb dating method of 1.49 cm a1, a vertical sediment flux of 1.04 g cnf2 a?and an organic carbon flux of 0.028 g cm2 &? The tide in the Yuehu is irregularly semidiurnal in character. The flood duration is shorter than the ebb duration, but the flood current velocity is smaller than the ebb current in the central part of the entrance channel. Here, sediment transport is directed to seaward, and the material in transition is dominated by bedload. Within the tidal basin, grain size trend analysis indicates that the sediments are transported towards the center of Yuehu. ii ABSTRACT For the past 20 years, because of inappropriate utilization of the inlet system by the local people, siltation in Yuehu has been accelerated and the ecosystem has been deteriorating rapidly. If no effective measures are taken to improve its water circulation pattern and ecosystem, Yuehu will be closed soon.