Channel Assessment Procedure Field Guidebook

[Table of Contents]
Figure 9c. Field indicators of channel disturbance-morphological features.


Field
code
Description Typical photograph

Field indicators: morphology
C1 Extensive riffles or cascades. In intermediate and large channel morphologies, the channel is dominated by riffles and relatively shallow pools or glides. In small channel morphologies, extensive riffles are replaced with extensive cascades. Occurs in all morphologies and both aggrading and degrading channels.
C2 Minimal pool area. Pools are limited in frequency and extent and are often only associated with individual pieces of LWD. Occurs in all morphologies and both aggrading and degrading channels.
C3 Elevated mid-channel bars. Channel bars have aggraded with bar-tops at equal elevations or higher than adjacent bank-tops. Typically, such bars have relatively steep downstream faces. Occurs in aggrading CP and RP morphologies.
C4 Multiple channels or braids. Multiple channels develop as the channel aggrades and shifts from past single thread to recent multiple channels. Typical of CP and RP morphologies, and occurs in aggrading channels.
C5 Disturbed stone lines. Steps associated with step-pool morphologies are disturbed (stone lines are no longer intact and water flows around individual stones, rather than cascading over actual stone lines). Occurs in SP and CP morphologies, typically in degrading channels (although may occasionally be present in aggrading channels).


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