Definition of Terms

There is a lot of technical terms on the Rivers and Streams website. This page is designed to help navigate and define these words and phrases. Use the line below to skip to a certain letter.
Bank angle:
Angle formed by the slope of the bank, measured in degrees from the horizontal.
Bank erosion:
Erosion of bank material caused by water current, wave action, or surface erosion.
Bank-full depth:
Depth of water measured from the surface to the channel bottom when the water surface is aligned with the top of the stream bank.
Bank-full discharge:
Maximum streamflow that can be held within the channel without overtopping its banks and spreading onto the floodplain.
Bank-full width:
Distance between the tops of the most prominent banks on either side of a stream channel.
Bank sloughing:
Slumping of saturates, cohesive soils near a water body that cannot freely drainage during rapid drops in water level.
A submerged or exposed accumulation of sand, grave, or other alluvial material formed in a water body along the banks. Common types of bars include alternate, braided, channel junction, delta, diagonal, dune, island, and mid-channel.
Base flow:
Water that percolates into the ground and is conveyed to the stream slowly over long periods of time, thereby sustaining streamflow during periods without rainfall.
Bed load:
Substrate moving on or near a streambed and frequently in contact with it.
Solid rock, underlying surficial deposits or exposed.
Bottom-dwelling organism including plants, invertebrates, and vertebrae animals that inhabit the benthic zone of a water body.
Biological indicies:
A measure of the health or condition of a water body based upon values for a specific biological or physical parameter.
Biological based standards used to assess or regulation water body conditions.
Use of biological characteristics of a water body to assess its health or condition.
A substrate particle larger than 25 cm (10 in) in diameter.
A stream that divides into a network of several branching and reuniting channels separated by bars.