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Three Weichselian Lateglacial (13‐10 ka) terraces have been distinguished in the Maas valley which were formed when the Maas repeatedly incised in an increasingly narrow floodplain. The River Maas changed from a braided system (before c. 12·5 ka) via a transitional phase to a high‐sinuosity meandering river (c. 12·5‐11 ka), to a braided system (c. 11‐10 ka) again and finally to a low‐sinuosity meandering river (after 10 ka). These fluvial style changes involved phases of erosion and deposition. The amounts of eroded, deposited and reworked sediment during each Lateglacial period are calculated in this paper. The sediment budgets allow comparison of the transport capacity of the different river styles, which will help to explain the observed fluvial changes. Borehole information regarding the thickness of terrace sediments and lateral extensions of the Lateglacial terrace surfaces were combined in a three‐dimensional approach, using a geographical information system. Multiple regression analyses were used in calculating altitudes of entire terrace surfaces from individual altitude measurements. It will be shown that the fluvial development of the Maas can be explained not only by climate‐related external factors such as sediment‐discharge ratios and discharge characteristics, but possibly also by intrinsic factors such as floodplain dimensions and the channel morphology of previous periods. Copyright © 1999 John Wiley & Sons, Ltd.

The influence of geology, discharge regime, slope, vegetation type, vegetation density and permafrost conditions on periglacial channel morphology has been investigated in the Usa catchment (northern European Russia). Rivers are dominated by meandering or anabranching plan forms and rarely show braiding characteristics, despite a nival discharge regime, the presence of discontinuous permafrost and locally steep slopes.The dense vegetation cover is an important factor in determining the meandering morphology as it inhibits the sediment supply and hence braided conditions. Differences in vegetation types (taiga in the south, tundra in the north) have no effect on channel plan form.