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Alluvial and colluvial sediment deposition form a vital record of environmental change during the Holocene. Firm chronological control on these archives is necessary to enable us to relate sediment dynamics to human activity and climate variability. In the Eastern Mediterranean, such relationships are hard to establish due to the lack of spatially well distributed sediment archives with good chronological control. This scarcity is problematic with respect to regional-scale reconstructions of the temporal variation of sediment dynamics. Here, we present a radiocarbon database (n = 178) of geomorphologic activity collected from multiple distinct sediment archives within the territory of Sagalassos in south-western Turkey. The data were grouped according to their sedimentary facies for analysis using cumulative probability distributions (CPD) and sedimentation rate (SR) modelling. Two small-scale colluvial valleys, where chronological information was abundant, were investigated in more detail.Results show that sedimentation chronology differs between individual, nearby cores, since it strongly depends on the local geomorphic situation. A generalizing approach combining multiple cores' results yields more widely valid conclusions. High sedimentation rates coincided with the initial major anthropogenic disturbance of the landscape and decreased afterwards, probably due to hillslope soil depletion. CPD and SR analysis indicates that generally colluvial sedimentation rates did not change much from 2000 BC onwards. River floodplain sedimentation, in contrast, increased markedly during the first millennium BC and during recent times and a significant time lag in enhanced sediment deposition between the upper and lower reaches of the river valleys was observed.

Humans have greatly impacted the processes and intensities of erosion, sediment transport and storage since the introduction of agriculture. In many regions around the world, accelerated floodplain sedimentation can be related to increases in human pressure on the environment. However, the relation between the intensity of anthropogenic disturbance and the magnitude of change in fluvial sediment dynamics is not straightforward and often non-linear. Here, we review a number of case studies from contrasting environmental settings in the European loess belt, the Eastern Mediterranean mountain ranges and the eastern USA. Detailed field-based sediment archive studies and sediment budgets covering time periods ranging from 200 to over 5000 year, as well as the use of pollen and sediment provenance techniques, show that no overarching concept of changes in floodplain sedimentation following anthropogenic disturbance can be established. Slope-channel (dis)connectivity controls the existence of thresholds or tipping points that need to be crossed before significant changes in downstream sediment dynamics are recorded following human impact. This coupling can be related to characteristics of human pressure such as its duration, intensity and spatial patterns, but also to the geomorphic and tectonic setting. Furthermore, internal feedback mechanisms, such as those between erosion and soil thickness, further complicate the story. All these factors controlling the propagation of sediment from eroding hillslopes to river channels vary between regions. Hence, only unique patterns of fluvial geomorphic response can be identified. As a result, unravelling the human impact from current-day sediment archives and predicting the impact of future human disturbances on fluvial sediment dynamics remain a major challenge. This has important implications for interpreting contemporary sediment yields as well as downstream sediment records in large floodplains, deltas and the marine environment, in terms of changes in the drivers of environmental change.

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