Niagara Falls, Canada. Abstract Many stream in southern Ontario are entrenched into glacial deposits and have irregular meanders confined in narrow valleys. While the glacial material is erodible, and streams have a morphology superficially like alluvial channels, the glacial material, especially clay till and coarse outwash gravel, restrict their adjustment and modify their morphology. Bed material size shows no systematic trend along these streams because it depends on the type of material exposed locally in the valley floor and walls. Channel beds often have a one grain veneer of alluvium overlying resistant clay till which also outcrops in the banks.
Floodplains are often only superficially alluvial.
Channel morphology sometimes resembles bedrock channels more than alluvial channels. Long sections occur without any obvious bed topography, and bends often have multiple pools and riffles and sometimes no pool at all. This unusual morphology presents a channel to channel design and restoration practices and negates the validity of simple text-book design based on classical alluvial channels.