Assessment of sedimentation volumes of the shipping channel in the port of Arkhangelsk

Abstract

Sedimentation is one of the natural negative factors limiting navigation and obliging to regularly carry out dredging. The navigable channel of the seaport of Arkhangelsk is significantly exposed by sedimentation processes, the annual volume of repair dredging is on average 1 million m³, which leads to environmental problems and economic costs. One of the tools for studying the sedimentation processes is the analysis of bathymetry and grain-size distribution of alluvial soils. The paper presents a quantitative assessment of the volume of a storm and the seasonal sediment accumulating regions of the ship channel of the seaport of Arkhangelsk in the example Mudyug, Solombala channels and the waters of the Bakaritsa handling area according to the digital models of the bottom topography, received during the annual hydrographic work from 2004–2017. The analysis of the grain-size distribution of alluvial soils in the water area of the selected objects was performed. It is established that on average precipitates about 200 thousand m3 of alluvial soil deposits on the Mudyug canal for one storm period. In addition, by constructing a regression model (coefficient of determination R2 = 0,682), a direct relationship between wind speed and storm drift volumes on the Mudyug chanmel was found. It is revealed that the maximum layer of alluvial soils is 275 cm, 67 cm and 65 cm during the seasonal period for the Mudyug, Solombala channel and the Bakaritsa, respectively, which are essential for the safety of navigation. The possible reasons for the accumulation and sources of alluvial soils for each zone in the seaport of Arkhangelsk are shown.