Geoecological Zoning of the Seaport of Arkhangelsk Water Area during Dredging

Abstract

Based on point classifications, methods for geoecological zoning of water areas during dredging have been developed. Fourteen factors and quantitative indicators of their assessment are proposed characterizing the degree of negative influence of dredging on the ecological state of water areas. An expert assessment of the influencing factors significance was carried out. The weighting coefficients of the factors were calculated by the ranking method. Geoecological zoning of the seaport of Arkhangelsk water area in the Northern Dvina mouth area was carried out during dredging operations by means of a point-rating assessment of the water area. The areas most susceptible to the negative effect of dredging are those with the largest observed volumes of annual sediment accumulation (sea canals in the estuarine seashore zone (Mudyug canal)) and those with the highest level of pollution of waters and bottom soils (water areas with active harbour and other technogenic activities (Bakaritsa)). Delta areas, in particular the Maimaksan channel, have the most favorable conditions for dredging with the least possible negative impact on the ecological situation. With regard to the mentioned objects, a verbal-numerical scale of geoecological assessment has been compiled. The method can be recommended for use in all tidal estuaries of rivers in the Arctic seas.