Density and grain size vary according to the amount of turbulence. Sediment Wedge Thick, wedge-shaped deposit of mixed soil, rock and organic debris injected into a stream channel by debris avalanches and debris flows from adjacent hillslopes. Gravitational deposit of transported material in flowing or standing water. Sedimentation Dam A dam which is designed to collect sediment from the water flowing over or through it, thereby filling in a portion of a streambed or gully. Seep An area of minor groundwater outflow onto the land surface or into a stream channel.
Flows are too small to be a spring.
Seepage Percolation of underground water through the banks and into a stream or other body of water. Seiche Resonant oscillation of a large body of water due to transient variation of atmospheric pressure. Seston Particulate matter suspended in water. Settling Basin Retention basin whose primary purpose it is to provide extremely low flow velocities to allow water-borne silt to settle out. The energy expended on the wetted perimeter of the stream increases proportionally with the energy slope and water depth.