These issues concern a section of the Lower Oder River which is approximately 110 km long, as well as the Lake Dąbie. They are jointly addressed by the two neighbouring countries. The key objective of the modernisation is to improve the conditions for navigation on the whole border section of the Oder River. It is supposed to ensure minimum depths of about 1.8 m at minimum firm flows in the Oder River, equal to 228 m3·s-1 on the section from the outlet of the Warta River to Widuchowa and 151 m3·s-1 from the outlet of the Lusatian Neisse River to the outlet of the Warta River. Another important objective is to improve the efficiency of ice-breaking operations and thus mitigate the risks caused by ice jamming. The channel of the Oder River was regulated in early 19th century with the use of a system of spurs located on both river banks. The regulation structures did not ensure the expected channel stability and navigable depths. In 1924–1941 corrections were made to the river regulation system with the use of spurs for the socalled low water level, however the efforts have never been completed. The crowns, heads and main bodies of the ...
The muds settled in the Lake Dąbie have visco-plastic properties. They contain many organic matter and are polluted by sewage from communities and industry. The presence of this substances changes clearly the dynamic properties of the fine grained material, as well the conditions of sedimentation and resuspension of solid particles. An important navigation way is located in the lake Dąbie with following parameters: length 14.5 km, width 150 m and guaranteed depth 3.2 m. This way is periodically deepened by dredgers. The authors have performed a preliminary estimation of the physical and rheological features of mud samples from the Lake Dąbie in the region of the navigation way. The thickness of the mud layer is equal 3–5 m. The fine grined sediments have a liquid consistency, and their water content is equal to some 300- 500%. The nominal granulometric size d50 changes between 12–15 μm for superficial muds and between 44-95 μm for bottom muds, and the organic matter content varies between 10 – 30%. The studies on rheological features of organic sediments proved that they behave as non-newtonian liquids. Their behaviour can be described by the twoparameter rheological model of Bingham. ...
The balance of Dąbie Lake water has been analysed in three ways: as daily balance, averaged balance in a decade calculated on the basis of Regalica river flows determined by Mikulski and Ostapska-Bojanowicz (1965), and the water balance based on flows in water-courses reaching Dąbie lake, which has been determined using the model of lower Odra steady flow (Buchholz 1991). The method based on Odra river hydraulic model has turned out to be most important in the examination of Dąbie lake water balance. The share of Regalica river in the general inflow to the lake (calculated on the basis of this model) is 73,5%, (6557,8 millions m3), Orli Przesmyk canal has 23,9% (2135,3 millions m3), drainage area contribution is 2,3 % (205,5 millions m3) and precipitation brings 0.33% (29.3 millions m3). The outflow is shared by Iński Nurt canal (84%, 7503,2 millions m3), Babina (15,63%, 1395,5 millions m3) and evaporation – 0,33% (29,9 millions m3). Total inflow in the average year of multi-year period is 8927,9 millions m3 of water. On the basis on 1948-1990 period it has been calculated that on average 65 water exchanges take place in the lake yearly. ...
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 ...
