Knowra Alluvium Alluvium Alluvium is loose sediment deposited by flowing water, especially in river channels, floodplains, and deltas. Its grains range from clay and silt to sand and gravel.
Sediment transport : The movement of mineral and organic particles by water, wind, ice, or gravity. Flowing water carries alluvial grains as dissolved load, suspended load, or bed load.
Sediment : Loose particles of mineral, rock, or biological material that can be transported and deposited. Alluvium is sediment distinguished by deposition from flowing water.
Alluvial soil : Soil developed in sediment deposited by rivers or other flowing water. Floods and channel deposits create fertile soils across many river valleys.
Colluvium : Loose material accumulated at the base of slopes through gravity-driven movement. Unlike alluvium, colluvium is deposited mainly by slope processes rather than flowing water.
Deposition (sedimentology) : The settling or accumulation of transported sediment when its transporting force weakens. A river deposits alluvium when flow loses enough energy to carry its grains.
Grain size : A measure of the diameter of individual particles in a sediment or rock. Grain size helps describe alluvium, from fine clay to coarse gravel.
Aquifer : A permeable body of rock or sediment that stores and transmits groundwater. Porous alluvial sands and gravels commonly store groundwater in shallow aquifers.
Loess : A wind-deposited sediment dominated by silt-sized particles. Loess is transported and deposited by wind, unlike water-laid alluvium.
Hydraulic sorting : The separation of sediment grains by differences in size, density, and transport behavior under flowing water. Changing current speeds sort alluvial grains into distinct layers and deposits.
Stratification (geology) : The arrangement of sediment or rock into distinct layers formed through deposition or other geological processes. Successive floods and channel shifts produce layered alluvial deposits.
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