The incision of the spit and fluvial sediment supply was also observed, in October 2009, by Yamashita et al. (2011), who reported the northeastward transport of fluvial sediment into the sand flat by a fluvial flooding event.
Knowledge of fluvial sediment supply to the coastal sediment budget is important for the assessment of the impacts on coastal stability.
A constant sea level in the middle to late Holocene, and continuous fluvial sediment supply, caused rapid bayhead delta progradation (highstand systems tract).
A substantial increase in fluvial sediment supply relative to transport capacity causes complex, large-magnitude changes in river and floodplain morphology downstream.
This study shows that the late Quaternary evolution of the Lower Tagus Valley is determined by a narrow continental shelf and deep glacial incision, rapid post-glacial relative sea-level rise, a wave-protected setting, and large fluvial sediment supply.
We suggest that these flooding surfaces, which occurred when sea-level in the Gulf of Mexico was rising < 2 mm/yr, were primarily driven by declines in fluvial sediment supply to the coast due to past climate changes.
Despite the damming of the four major rivers discharging into the Santa Barbara Cell, and the apparent reduction in fluvial sediment supply, there has been no systematic or significant reduction in the dredging rates at any of the harbors.
A number of general glacial fluvial landform relationships are identified and can be broadly clustered into three themes: 1) topographic and sedimentological glacial legacy effects; 2) landforms resulting from isostatic and lake baselevel change, and 3) superimposed patterns of Holocene fluvial sediment supply.
Therefore, the stratigraphic architecture and evolution of the Doce River deltaic plain suggest that fluvial sediment supply and relative sea-level fluctuations related to Quaternary global climatic changes and local tectonism exerted major controls on sedimentation through the variation of accommodation space and base-level changes.
It is estimated that the fluvial sediments supplied to the sand flat were dispersed by wave or tidal currents during normal conditions.
