Summary:

Estuary. During the winter inundations, this lake constitutes the receiver of ice jam from the river. This lake is intensively silted by river sediments type sand, silt and clay, delivered mainly by Regalica (the eastern branch of Odra) and by the rivers Ina and Płonia. The water volume of the lake decreased during 34 years (1962–1996) by 12,1 mln m³. The mean increase of sediments volume is equal 356 000 m³ * year^-1. The processes of sedimentation and erosion of muds are complicated by the waving of water level and by superficial and bottom currents. These currents are generated so by river inflow as by wind, causing changes of sea level during storms. Through this lake goes the main navigation way between Schwedt and the Pomeranian Bay. Its deepening is planned in the period 2007–2011, by dredging of 810000 m³ of bed sediments. This fairway has following parameters: length 14,5 km, width 150 m and depth 10m. The geotechnic measurements have shown that the thickness of muds is equal 3-5 m. The cohesive sediments contain 10-30% of organic matter and have a liquid consistency. Below the organic sediments, mainly fine sands occur. The muds are polluted, mainly by heavy metals as Al, Zn, Cu, Cd and Hg, and by oil compounds. The storage of the excavated material in the valley is a technical problem, because of the possibility of the contamination of the soil and of the ground water.