Abstract:According to collected survey data of the coastal zone in Rizhao city, the ancient channel sections exposed in several shallow formation sections are conjectured, the old channel system is reconstructed, and the distribution characteristics of the ancient channel in Rizhao coastal zone have been analyzed comprehensively. In Rizhao offshore area, there is a comb like channel network with the SW—NE trend main channel. The ancient channel was formed in the last glacial period about 44000 years ago. The formation of ancient river channel is the result of many factors, such as river erosion, transportation, sedimentation, sea level rise in the later period, tidal transformation and so on. In the last glacial period, the climate in the study area is humid, the flow velocity of the river is large, and the ability of the river to transport sediment is strong. Under the long-term erosion, the ancient river channel is cut, and the sand body carried by the river with more deposition is easy to form in the ancient river channel. The cross section of ancient river channel is mainly U-shaped, V-shaped, W-shaped, box shaped and inverted trapezoid. In the north west side of the main river, the branch river is dense, and in the south east side, the branch river is sparse. The main river course is about 40km long, and its cross section is gradually widened from southwest to northeast, with the widest section reaching 4km. Most of the branch rivers are in the NW direction, a few are in the NE direction, the length is between 8~20km, and the width is about 1~3km. The ancient channel is mainly located outside the closed depth of 16~24 m depth, and the sand body can be used as the sand source for artificial sand throwing in the future.
