Abstract:At the Satino site in the center of the Russian Plain, major events of the Holocene erosion history are concentrated on sides of river valleys incised into smooth moraine landscape. Valley sides are dissected by Pleistocene gullies. Extraordinary for the Holocene was formation of four new permanent gullies. Three of them had appeared in the Late Atlantic -Early Subboreal time. One gully permitted direct dating of the fan base, which gave estimation of its appearance between 4.3-4.6 ka BP (cal). Two other gullies were constrained within the two intervals 5.2-5.5 and 5.9-6.2 ka BP (cal), based on assumed correlation with extreme runoff events dated over the area. After a long break of erosion, two of the gullies had exhibited the second phase of activity between 3.0-3.7 ka BP (cal). As in the Bronze Age no settlements are known in the study area and surroundings; human reinforcement of erosion was minor if any. The four intervals of extraordinary linear erosion on valley sides coincided with extremely high runoff events in streams of various sizes, which left prominent geomorphic and sedimentological features: meander arcs, coarse-grained alluvium, buried floodplain soils, etc. Altogether, this is considered to indicate a highly irregular climatic pattern in the area in the interval of 3.0-6.2 ka BP (cal) with several phases containing a series of extreme downpours, which had no analogs throughout the Holocene.

Abstract:Białka is a typical river that has its origins in the high mountains of the High Tatra and the Belanske Tatra Mountains. Transport of gravel from the Tatra Mountains down to the foot of the mountains over a long period of time, during the Pleistocene and the post-glacial era, led to the formation of a typical braided river channel. During the last 150 years the river channel was gradually narrowed and deepened. This process has clearly intensified since the end of the 1960s due to human intervention that changed the course of the river channel. Exploitation of the river channel by extraction of sediment also had an impact. From the geomorphological and ecological point of view, the changes occurring in the Białka River channel, which are still continuing, are not progressing in a positive direction.

A. Analyses of sand sizes used in flume experiments and fed into flume-river. _ _ _ _. _ _ _ _ _ _ _ B. Data o n size characteristics of sand on channel bed and on bars in flume-river.__ _ _ _ _ _~-~- .- .-C. Summary of data on flume experiments a t California Institute of Technology .__._-~ ~. .- .-D. Comparison of hydraulic characteristics of uiidivided and divided reaches of braided streams.

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