Seafloor Topography and Surface Sediment Characteristics in the Western Sea Area of the Rizhao Port
JIANG Fei
LI An-long
ZHUANG Zhen-ye
Abstract：The bathymetric and bottom sediment data are of great significance for port channels,anchorage planning and environmental assessment after the port construction. However,there is a lack of such data for the southward-expanded waters of the Rizhao Port.In order to provide helpful suggestions for the rational layout in the southward-ex-panded waters of the Rizhao Port,bathymetric survey and bottom sediment investiga-tion were carried out in the western 50 km2 waters of the southward-expanded sea area of the Rizhao Port by using single beam echo sounding and clam type sediment sampler. The results show that the western sea area of the Rizhao Port can be divided into four water depth zones,in which the seafloor topography and sediment characteristics can be described as the followings:1)the Channel Zone:the shallow channel zone is about 500 m wide and has a water depth deeper than 1 1 m.The isobathic lines there are parallel to the dock water front and four grades of stepped topography inclining southward are formed.In the dredging center of deep channel the water depth reaches to 24 m and a-round the dredging center the isobathic lines show a semielliptical shape with an opening to the south.At the entrance of the opening the water depth is 23 m.The bottom sedi-ments in this zone are dominated by medium sorted gravelly sand;2)In the Harbor Ba-sin Zone,which includes the nearshore area from the southern Rizhao Port to the ash dam of power plant and is highly concentrated with fishing harbors,the water depth is shallower than 6 m and increases gradually toward the south.The isobathic lines are parallel to the harbor shoreline.The seafloor is even,with a gradient ratio being 3‰. The bottom sediments are dominated by well sorted silt and sandy silt,with small a-mount of poor sorted muddy and sandy gravel occurring in the nearshore area;3)In the Estuary Zone from the Taoluo River to the Futuan River,underwater delta topography is evident.The isobathic lines shallower than 5m show an arc-shape and protrude south-eastward,with the maximal gradient ratio being 14.2‰.The bottom sediments in this zone consist mainly of excellently sorted sand and silty sand;4)In the Shallow Water Zone,the seafloor is even,with the average gradient ratio being 1.9‰.The 6 ~ 10 m isobathic lines extend parallel toward the offshore along the northeastern direction and then deflect eastward near the southward-expanded dock.The bottom sediments are mainly composed of well sorted sandy silt and silt and show a coarse-fine-coarse banded distribution toward the deep waters and parallel to the coastline.The sediment distribu-tion is basically consistent with the water depth conditions.However,the coarsening of sediment in the deep waters may probably be due to the current deflection caused by the southward-expanded dock.The bottom sediments tend to move southward.
Keywords：western waters of the Rizhao Portbathymetric surveyanalysis of bottom sedimentseafloor topographysediment characteristics
Publication Date：2016-01-01
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)
Pages：11( 32-42 )