backwater analysis — A hydraulic analysis, the purpose of which is to 



compute the water surface profile in a reach of channel with varying 

 bed slope or cross-sectional shape, or both. 



bank — A comparatively steep side of a channel or floodplain formed by an 

 erosional process; its top is often vegetated. 



bank-full discharge — Discharge corresponding to the stage at which the 

 overflow plain begins to be flooded. 



bar — An al I uv i a I deposit or bank of sand, gravel, or other material, at 

 the mouth of a stream or at any point in the stream flow. 



beaded stream — A sma I I stream containing a series of deep pools intercon- 

 nected by very small channels, located in areas underlain by permafrost. 



bed — The bottom of a watercourse. 



bed load — Sand, silt, gravel or soil and rock detritus carried by a stream 

 on, or immediately above its bed. 



bed load material — That part of the sediment load of a stream which is 



composed of particle sizes found in appreciable quantities in the shift- 

 ing portions of the stream bed. 



bed, movable — A stream bed made up of materials readily transportable by 

 the stream flow. 



bed, stream — The bottom of a stream below the low summer flow. 



braided river — A river containing two or more interconnecting channels 



separated by unvegetated gravel bars, sparsely vegetated islands, and, 

 occasionally, heavily vegetated islands. Its floodplain is typically 

 wide and sparsely vegetated, and contains numerous high-water channels. 

 The lateral stability of these systems is quite low within the boun- 

 daries of the active floodplain. 



carrying capacity, biological — The maximum average number of a given organ- 

 ism that can be maintained indefinitely, by the habitat, under a given 

 regime (in this case, flow). 



carrying capacity, discharge — The maximum rate of flow that a channel is 

 capab I e of pass i ng . 



channel — A natural or artificial waterway of perceptible extent which 



periodically or continuously contains moving water. It has a definite 

 bed and banks which serve to confine the water. 



configuration — The pattern of a river channel (s) as it would appear by 

 looking vertical ly down at the water. 



contour — A line of equal elevation above a specified datum. 



596 



