Research was conducted in valleys of sinuous rivers that drain medium-high mountain, foreland basin and upland areas, where loose Quaternary deposits predominate. The cyclic pattern determined for deposits of the oxbow sedimentary subenvironment in the Upper Odra Basin can be expressed as a few alternative sequences. The best-developed cycle occurring on a relatively high level of probability, is represented by the unilateral transition from channel to overbank deposits and upwards-bilateral oscillations between overbank and biochemical, as well as biochemical and slope deposits. In the first stage, oxbow filling processes are usually determined by autocyclic factors (resulting from spatial relations between abandoned channels and the active channel). As a consequence, overbank and/or biochemical sediments usually overlie channel deposits. Later, allocyclic processes could easily dominate autocyclic processes. In these cases, overbank, slope and late-Holocene alluvial fan deposits were delivered to oxbow basins as a result of the influence of outside factors such as climate or human impact. In the Upper Odra catchment, facies succession in the sequences of deposits infilling abandoned channels was mainly determined by climatic factors (in the Late Vistulian, early and mid-Holocene) and anthropogenic factors (in the late Holocene, especially in the last dozen centuries or more). The course of sedimentary processes conditioned by climate and human activity was modified by orographic factors associated with spatial relations among abandoned channels and both the active channel as well as valley slopes. However, the geological structure had a smaller influence on the course of sedimentary processes in the oxbows. The diversity of bedrock lithology in the individual drainage areas determined the thickness and lithological features of the given series of deposits but not the facies succession.

Lithological analyses and radiocarbon dating were used to elucidate the patterns and controls of Late Quaternary valley floor development of the Kłodnica River, the Upper Odra Basin. The research results were discussed with data obtained from valleys of rivers draining piedmont basins and highlands of southern Poland. In consequence, five stages of morpho-sedimentary evolution of the Kłodnica valley were distinguished. In the Late Vistulian a large-scale deposition of channel alluvium took place in the conditions of high river discharges. This sedimentary style probably still existed in the Early Pre-Boreal as long as open grass communities survived in the Kłodnica catchment. The next phase, in the Late Pre-Boreal and Boreal, is characterized by a significant increase in accumulation rate of biochemical facies.. The considerable restriction of minerogenic deposition was connected with widespread of forest and gradual limitation of the river discharges. The third stage began at the decline of the Boreal and was defined by decrease of accumulation rate or even biogenic accumulation break. Synchronously, periodic increases of fluvial activity were noticed in the form of cutoffs of meander loops and overbank deposition in oxbows. The beginning of the fourth period took place not earlier than in the Early Sub-Boreal. This stage was distinguished by renewed peat growth/increase in biochemical accumulation rate and periodic increase in alluviation, generally taking place in the conditions of low channel-forming flows. The latest phase (from the Middle SubAtlantic till now) is characterized by common initiation of slope deposition and a rapid increase in fluvial sedimentation, especially overbank and tributary fan facies. An increase in minerogenic deposition occurred in response to human impact, which became more significant from the Roman Period and occurred on a large scale from the early Middle Ages. Older settlement phases, including intense settlement from the Hallstatt Period, were not clearly recorded in the Kłodnica valley fill.

The analysis of the positive feedback between landslides and erosion requires determination of the precise temporal and spatial relations between events of colluvium delivery and fluvial erosion. In our study we use decennial datasets on the occurrence of landsliding and erosion achieved through dendrochronological methods. Four sites covering areas of landslide slopes and adjacent valley floors with stream channels were studied. Landsliding on slopes was dated from the tree-ring eccentricity developed in stems tilted due to bedrock instability. Erosion in channels was dated using the wood anatomy of roots exposed by erosion of the soil cover. Analysis of the temporal relations between dated landsliding, erosion and precipitation record has revealed that two types of repeating sequences can be observed: (1) rainfall → landsliding → erosion; (2) rainfall → erosion → landsliding. These sequences are an indication of the occurrence of slope-channel positive feedback in the sites studied. In the first type, landsliding triggered by rainfall delivers colluvia into the valley floor and causes its narrowing, which in turn causes increased erosion. In the second type erosion triggered by rainfall disturbs the slope equilibrium and causes landsliding. Landsliding and erosion, once triggered by precipitation, can occur alternately in years with average precipitation and reinforce one another. Bidirectional coupling between landsliding and channel erosion was shown notably through the effects of channel shifting and forced sinuosity and by increased erosion of the slopes opposite the active landslides. Observations also suggest that the repetition of sequences described over longer periods of time can lead to a general widening of the valley floor at the expense of slopes and to a gradual change of the valley crossprofile from narrow, V-shaped into a wide flat-bottomed. Thus landsliding-erosion coupling/positive feedback was recognized as an important factor shaping hillslope-valley topography of the mid-mountain areas studied.

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