The Upper Odra valley on sector between Chałupki (km 20,0) and Olza mouth (km 28,0) is subject of deformations caused by natural factors and by human activity. This sector constitutes the border river between Poland and Czech Republic. Seven unique meanders exist here. The I-st and the IV-th meander have been broken during the floods in 1997 and 1967. Together with road bridge (km 20,530) they constitute three critical places with regard to flow capacity of Odra valley in its upper course. The problem of the border between both states Poland and Chech Republic on this sector is still not solved, what causes serious lawful and economic complications. The studied sector is distinguished by intensive bank erosion and sedimentation. The dynamic of Odra morphological processes is high here, so changes of water course as well as shape of the riverbed are very indicative. At present, the new channels formed within the meanders I i IV are characterized by the rapid flow caused by the high bed slope. From the authors’ studies it follows, that the old river branches permit to pass only a small percentage of the average discharge. Great outwashes, islands and dense vegetation within the meanders cause a ...
Paper concerns the investigations of riverbed sediments in the meandering sector of the Border Odra, In the frame of meander I. As a result of fluvial processes the Odra riverbed is exposed to deformations, leading to often changes of the river itinerary. In the historical time, many meander breaks were registered, the last in 1967 (Meander IV) and in 1997 (Meander I). In the old river bed the discharge is gradually decreasing and the substantial part of the discharge is flowinging through the new channel. It leads to gradual silting of the old river part. The intensive formation of bars and of islands is observed. In the upper part of the old meander, mainly the bed load is deposed, and in the middle and lower part – the suspended load. The superficial part of the layer (cover) is exposed to the formation of pavement. The size of the pavement cover is equal 8,4–9,8 cm, and the granulometry of the lower layer (20–40 cm) equal to d50 = 2,3–2,9 cm. The islands formed by fine sediments were covered in 3-4 years by intensive vegetation (trees and bushes). This process causes an important decreasing of flow velocity in the old channel. The ...
