Bed Load Sediments
Bed load sediments are those that are transported in constant contact with the bed of the tributary before they are deposited. The sediments stay close to the bed of the tributary because they are of larger size. These deposits can exist as bars: expansion bars, longitudinal bars, crescent-point bars, and pendant bars. Expansion bars are those that form within the middle of the tributary while longitudinal bars form along the side. Crescent-point bars form on the lee side of the bend of a tributary. Pendant bars extend down current as they form around an obstruction in the tributary. They are named as such because they look like a pendant that hangs around the neck.
Suspended Load Sediments
Suspended load sediments are those that are transported in the water of the tributary and are supported by turbulence before they are deposited. These deposits can exist as slackwater and eddy deposits. Slackwater deposits are those of finer particles in lower energy areas such as basins or ponds, while eddy deposits occur in areas of lower flow velocity such as tributary mouths. But sometimes bed load sediments work with suspended load sediments as is the case with the Lake Sacajawea Flood Bar (See References 4). Here, a pendant bar and an eddy bar come together to form one of the tallest Ice Age longitudinal flood bars.
Washload Sediments
Washload sediment, otherwise known as fine sediment load, is a concept described as sediment that is washed clean by water in a concrete channel. Because there is no significant trace of the sediment, it must then be considered washload. It is dependent on the supply of fine sediments and the upstream flow conditions. Determining what particles are washload is rather analytical and has been narrowed to three criteria: grain diameter, transport capacity and sediment size finer than 0.0625 mm.
Drift
Drift is the term used for the deposits of glacial ice and its meltwater, including glaciofluvial and till deposits. These deposits have sediments of varied sizes mixed with layers of pollen and soil, known as the till. Glaciofluvial describes the stratified deposits from glacial meltwater. Glaciers deposit sediments along the sides and toe of the ice forming ridges known as moraines. Lateral moraines form from till deposited to the side margins of a glacier. Medial moraines form when two tributary valley glaciers join and their lateral moraines merge. End moraines are the sediment carried forward by glaciers while terminal moraines are end moraines marking the furthest advance of a glacier. Recessional moraines are end moraines deposited by a retreating glacier. Retreating glaciers deposit till on the floor of the glacier trough, and the landscapes created by these deposits are ground moraines.