[Mapping and Assessing Terrain Stability Guidebook Table of Contents]

Appendix 4. Example classification and criteria for assessing the risk of sediment delivery to streams

Risk of sediment

Proximity of stream channel to polygon delivery to streams

 

No stream channel in or adjacent to polygon

Minor stream* channel in or adjacent to polygon

Major stream** channel in or adjacent to polygon

Very Low

Gentle to Steep slope

   

Low

 

Gentle slope

 

Moderate

 

Moderate slope

Gentle slope

High

 

Steep slope

Moderate slope

Very High

   

Steep slope

 

Slope steepness downslope from polygon to stream channel

* Minor streams are those perennial streams with channel widths that are less than or equal to 1.5m, or any ephemeral stream.
** Major streams are perennial streams with channel widths that are greater than 1.5m.

Note: Perennial streams are defined in this guidebook as any stream where it is reasonably likely that the stream flows after July 15 (during the summer period) in most years.


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