Definition of Terms

 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.
ABCDEFGHIJKLMNOPQRSTUVWXYZ
TermDefinition
Sand:
substrate particles between 0.062 and 2 mm (0.00003-0.01 in) in diameter.
Sediment:
Fragmented inorganic and organic material that is suspended in, transported, and deposited by water or air.
Sedimentation:
Action of forming and depositing sediments.
Silt:
Fine soil that is between 0.004 and 0.062 mm (0.00002-0.0003 in) in diameter.
Siltation:
Settling of fine suspended sediments in water where velocity is reduced.
Sinuosity:
Ratio of channel length between two points in a channel to the straight line distance between the same two points.
Stage:
Elevation of a water surface above or below an established reference point.
Stream:
Natural water course containing flowing water, at least part of the year, that supports living communities within the channel and riparian area.
Stream order:
Hierarchical ordering of streams based on the degree of branching. For example, a first-order stream is an un-forked stream. Two first-order streams flow together to form a second-order stream, etc.
Stream power:
Stream power is the amount of work performed by the stream flow per unit time, which can be expressed relative to a unit of stream bed area or length of channel. Power is traditionally expressed in watts, which ultimately can be expressed as ML2/T3 , where the dimensions include: M = mass, L = length, T = time.

 

  1. Stream power per unit area [? a (M /T3 -or- watts/L2)] can be defined as a product of the shear stress [t (M/LT2)] and average velocity [V (L/T)]. That is, ? a = t V.
  2. Stream power per unit length of channel [? l (ML / T3 -or- watts/m)] can be defined as a product of the water density[? (M/L3)], acceleration of gravity [g (L/T2)], discharge [Q (L3/T)], and water surface slope [S(L/L)]. That is, ? l = ? g Q S.
Suspended solids:
particles of unfiltered, undissovled solid matter such as soil that are present in water.