Rated based on the depth, complexity, and functional importance of riffle/run habitat in the segment, with highest scores assigned to segments dominated by deeper riffle/run areas, stable substrates, and a variety of current velocities.
| Range | Category |
|---|---|
| 0 - 5 | Riffle/run depth < 1 cm; or riffle/run substrates concreted |
| 6 - 10 | Riffle/run depth generally 1-5 cm; primarily a single current velocity |
| 11 - 15 | Riffle/run depth generally 5-10 cm, variety of current velocities |
| 16 - 20 | Riffle/run depth generally >10 cm, with maximum depth greater than 50 cm (maximum score); substrate stable (e.g. cobble, boulder) & variety of current velocities |