Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Basic Hydraulics: Solids Transport What is sediment? • Matter that settles to the bottom of a liquid • Matter transported by water or wind • May be particles that are derived from rocks, biological materials, or chemical precipitates • Highway sediments may be a mix of materials, including pavement dust, natural soils, vehicle rust particles, tire dust particles. Soil erosion (scour) • Caused by impact and dislodgment of individual soil particles by rain drop impact. • Caused by flow of water over soil surfaces. • Caused by movement of water in channel systems. Erosion and transport mechanisms • • • • Rill and sheet erosion Gully erosion Bed and bank erosion Suspended material transport • Bed material transport • Wash load transport Australian Dept. of Environment Rill erosion progressing to gullies Suspended material transport • Channels accumulate sediment from sheet/rill and gully erosion • Lighter sediment carried as suspended material • Heavier materials settle to bottom, added to material eroded from banks and bed Bed material transport • Stream bed load is part of total sediment load that moves along bottom of channel • Sediment particles roll, bounce, or slide along bottom • When stream has ability to re-suspend, some of particles will move • When it loses ability to carry particles in suspension, they will drop out again • Depends on local stream velocity and settling velocity of individual particles Wash material transport • Material that tends to flow through a reach without significant interaction with the bed • Material is usually coarse sand, smaller in size Solids transport – bed & suspended load • El Paso District Solids transport – bed & suspended load • Terrell County Solids transport – debris • Also have bouyant solids (debris) in the flow