suspended load — The portion of stream load moving in suspension and made 



up of particles having such density of grain size as to permit movement 

 far above and for a long distance out of contact with the stream bed. 

 The particles are held in suspension by the upward components of turbu- 

 lent currents or by colloidal suspension, 



talik — A zone of unfrozen material within an area of permafrost. 



terrace — An abandoned floodplain formed as a result of stream degradation 

 and that is expected to be inundated only by infrequent flood events. 



thalweg — The line following the lowest part of a valley, whether under 

 water or not; also usually the line following the deepest part or 

 middle of the bed or channel of a river or stream. 



thermokarst — Landforms that appear as depressions in the ground surface 

 or cavities beneath the ground surface which result from the thaw of 

 ice-rich permafrost material. 



top width — The width of the effective area of flow across a stream chan- 

 nel . 



velocity — The time rate of motion; the distance traveled divided by the 

 time required to travel that distance. 



wash load — In a stream system, the relatively fine material in near-perman- 

 ent suspension, which is transported entirely through the system, 

 without deposition. That part of the sediment load of a stream which is 

 composed of particle sizes smaller than those found in appreciable 

 quantities in the shifting portions of the stream bed. 



water quality — A term used to describe the chemical, physical, and biolog- 

 ical characteristics of water in reference to its suitability for a 

 part i cu I ar use. 



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