Particle size measurements and end-member modelling suggest increased fluvial transport of the sediment.
Unlike fluvial archives from the humid mid-latitudes, semiarid Southwest Mediterranean alluvial archives exhibit phases of increased fluvial dynamics under generally drier conditions.
Increasing fluvial activity of wet epochs formed open landscapes even in small valleys, and decreasing flow during arid time spans allowed valleys to be overgrown with forest.
In addition, humid conditions would have favoured the extension of sedge-rich vegetation (Cyperaceae, of which 20 60% are C4 plants in this region128) in riverine swamps and floodplains along the river course, explaining the detected increase in Cyperaceae pollen at times of increased fluvial discharge (Fig. 2).
Slight rises in regional precipitation produce elevation of the water table and increase of fluvial discharges that provide water and sediment to the system.
A substantial increase in fluvial sediment supply relative to transport capacity causes complex, large-magnitude changes in river and floodplain morphology downstream.
The resulting increases in "fluvial flow" downstream created the second type of reason for closing the barrier – protecting vulnerable locations just upstream from Teddington, such as the village of Thames Ditton and the residential Trowlock Island.
Gully erosion is commonly associated with agricultural landscapes where vegetation clearance and farming practices increase runoff, leading to fluvial incision.
Impacts on landforms include thermokarst subsidence, increased hillslope instability, enhanced fluvial and lacustrine erosion, ice wedge degradation, frost mound thawing, thaw lake expansion, and degradation of palsas.
Fluvial flooding increases in the wetter climate scenarios, but there are few cells which change class between scenarios due to the strong influence of topography, i.e. the flood prone zones.
