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.
Overhead cover or branches and foliages from adjacent vegetation.
A life history strategy that includes migration between fresh- and saltwater. Fish reproduce and spend their early life in saltwater, migrate into freshwater to grow, and return to saltwater as adults.
The land area above a specific point from which water drains towards a water body.
Catchment area:
The total area draining into a given water body.
A natural or artificial waterway that periodically or continuously contains moving water, has a definite bed, and has banks that confine water at low to moderate streamflow.
Channel bottom:
The submerged portion of the channel cross section.
the mechanical alteration of a stream by deepening or straightening an existing channel or creating a new channel to facilitate water movement.
Channel unit:
Relatively similar areas of a channel that different in depth, velocity, and substrate characteristics from other areas, creating different habitats in a stream. Common types of channel units include: cascade, chute, falls, rapids, riffles, run, glide, and pool.
Stream substrate particles between 64 and 128 mm (2.5-5 in) in diameter.
Gently inclined surface at the base of a slow that represents a transition between landforms. Characterized by erosion, transport and sites of deposition.
A measure of the ability of a solution to carry an electrical current. Dependent on the total concentration of dissolved, ionized substances in an solution.
The location where two streams flow together and form one.
A small lotic system that serves as a natural drainage course for a small basin.
A passage, typically a pipe that is beneath a road or railroad to transport water.
Water moving in one direction and the speed at which it is moving.