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Sediment transport processes are a key mechanism of ecological change in riverine systems, and certain levels of sediment flux are necessary for healthy ecosystem functioning. Altered flow regimes and sediment mobility are contributing to a global problem of higher substrate embeddedness reducing the frequency of substrate scour events and leading to increases in periphyton accrual. Excess periphyton accrual leads to fish and invertebrate kills from oxygen depletion, degraded ecological health, altered sediment dynamics, deterioration in water taste, and odour nuisance. In recent decades, reports of toxic periphyton proliferations have increased and are linked with health problems in humans including asthma, skin rashes, liver damage, and the death of domestic dogs. Excess periphyton accrual is prominent in impounded catchments where dams have a considerable impact on flow and sediment regimes. With at least 3,700 large dams currently under construction or in the planning phase the problem is set to increase in the foreseeable future. Hydrological limits are widely implemented by authorities in an attempt to manage periphyton accrual. Hydrological limits are frequently based on flow-ecology relationships but are often ineffective. Sediment transport thresholds have been found to have a better relationship with periphyton accrual than hydrological metrics. Flow-ecology relationships do not account for the mechanisms of periphyton removal (scour, abrasion, and molar action) which are likely to vary between sites at equivalent flows, and the species-specific resistance to each mechanism also likely varies. Abrasion and molar action result from transport of sediment. Improving the effectiveness of hydrological limits as a tool for river management therefore relies on setting flows with the aim of inducing sediment transport to initiate mechanisms of periphyton scour. This will require models which can accurately predict the flow required to induce different phases of sediment trans

In a fluvial system, mountain basins control sediment export to the lowland rivers. Hence, analysis of erosion processes and sediment delivery patterns in mountain basins is a key factor for many applications such as land‐use management, hazard assessment and infrastructure design. Several studies have investigated the alterations triggered by recent climatic change on the hydrological regime, while only a few works have explored the consequences on fluvial sediment dynamics. Here, we combined and analyzed the quasi‐unique dataset of climatic conditions, landform response and sediment export produced, since 1986 in the Rio Cordon basin (5 km2, Eastern Italian Alps) to examine the sediment delivery processes occurring in the last 3 decades. The temperature, precipitation and fluvial sediment fluxes in the basin were analyzed using continuous measurement executed by a permanent monitoring station, while the evolution of sediment source areas was investigated using three sediment source inventories. The results showed that during the period 1986–1993 the sediment fluxes (339 Mg yr−1) reflected the stable trend of the climatic conditions. The period between the first and second source inventory (i.e. 1994–2006) was characterized by climatic fluctuations and by the occurrence of high magnitude floods. Nevertheless, a limited increase in the extent of sediment source areas was detected, suggesting that the increased sediment export (759 Mg yr−1) was mainly driven by in‐channel sediment supply. Notwithstanding the marked climate warming and the increased precipitation, a weak source area evolution and a reduction in sediment export (237 Mg yr−1) were observed during the period 2007–2015. In particular, the higher rainfall did not result in an intensification of flood events, stressing the absence of hillslope‐channel connectivity.