The subject of river sediment transport has been studied from centuries - by river engineers as well as geographers, geologists, river morphologists and fluvial geomorphologists. Up to now there are no well known complex methods and/or approaches with help of which one can determine the intensity of sediment transport. However, even the approximate knowledge of the quantity of sediment transport is important, especially when dealing with sedimentation of river deltas, and lakes, designing artificial water reservoirs and planning any river engineering works or designing hydraulic structures. The appropriate assessment of the intensity of sediment transport has the direct influence on an adequate functioning of any hydraulics structure or object, with the help of which the negative influence of sediment transport is eliminated (erosion, channel cutting, filling-up river and water reservoir water intakes). One has to bear in mind that all phenomena connected with sediment transport are very complicated and complex and belong to the most poorly recognized in river hydraulics, thus the best way to understand them is to do measurements directly in the field. This is especially recommended for mountainous streams and rivers. However, in practice, when we suffer the lack of huge financial support (since all river measurements ...
The results of investigations carried out in the stream Bukowiński are pre-sented in this paper. The aim of investigation was definition of influence of wood jam on change of dimensionless coefficient of resistance and coefficient of rough-ness. The performed measurements included cross-section leveling and longitudinal leveling of the stream channel, bed sediment sampling, and hydrometric meas-urements. Cross-section leveling included five cross-sections in the 47-m long stream sector; these were located upstream and downstream the wood jam and in its region. Differentiation of water flow velocity in the region of wood log was shown. The dimensionless coefficient of resistance was calculated taking into ac-count the equivalent bottom roughness determined by use of Gladki`s formulae [van Rijn 1984]. In the aim of the qualification of the equivalent bottom roughness three samples of bottoms sediment were taken in the cross-section with the log. It was found that the wood log in the Bukowiński stream caused a change of hydraulic conditions of water flow and, in consequence, the dimensionless coefficient of resistance in the wood jam section increased by about 71%. The coefficient of channel roughness was also determined and it was shown that the coefficient of roughness in the section of wood jam, ...
