Effects of Ice Covers on Alluvial Channel Flow and Sediment Transport Processes

• Main Authors: Sayre,W W, Song,G B
• Other Authors: IOWA INST OF HYDRAULIC RESEARCH IOWA CITY
• Format: Text
• Language: English
• Published: 1979
• Subjects: Hydrology; Limnology and Potamology; Snow; Ice and Permafrost; *SEDIMENT TRANSPORT; *ICE; *STREAMS; WATER FLOW; ALLUVIUM; SHEAR STRESSES; SAMPLING; CHANNELS(WATERWAYS); HYDRAULIC MODELS; COLD WEATHER TESTS; *Ice cover; Ice; permafrost
• Online Access: http://www.dtic.mil/docs/citations/ADA066991; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA066991

Ice covers cause a number of changes in alluvial channel flows by approximately doubling the wetted perimeter and thereby producing a redistribution of the boundary and internal shear stresses. A series of flume experiments was conducted to investigate the effects of simulated ice covers on various characteristics of alluvial channel flows. In comparison to free-surface flows with the same unit discharge and energy slope, flows with simulated ice covers were found to have substantially larger depths and lower average velocities. Due mainly to the lower velocities sediment discharges were found to be sharply reduced. Flow in an ice-covered channel is divided by a plane of zero shear stress into a lower and an upper layer. To the extent that the shear stress and velocity distributions in the lower layer are the same as in a free surface flow with the same mean velocity, and depth equal to the thickness of the lower layer, relationships developed for flows in alluvial channels with a free surface can be used for predicting several features of flows in ice-covered alluvial channels. (Author)