Rated based on the variety and spatial complexity of slow- or still-water habitat within the sample segment. It should be noted that even in high-gradient segments, functionally important slow-water habitat may exist in the form of larger eddies. Within a category, higher scores are assigned to segments which have undercut banks, woody debris or other types of cover for fish.
| Range | Category |
|---|---|
| 0 - 5 | Pool/glide/eddy habitat minimal, with max depth <0.2 m, or absent completely |
| 6 - 10 | <10% pool/glide/eddy habitat, with shallows (<0.2 m) prevalent; slow water areas with little cover |
| 11 - 15 | 10-50% pool/glide/eddy habitat, with deep (>0.5 m) areas present; or >50% slow water with little cover |
| 16 - 20 | >50% pool/glide/eddy habitat; both deep (>.5 m)/shallows (<.2 m) present; complex cover/&/or depth >1.5 m |