ENTRENCHMENT RATIO
Entrenchment is a measure of the vertical confinement (bank height) of the stream. The entrenchment ratio is determined by dividing the width of the flood prone area by the bankful width. The flood prone area is defined by measuring the width of the channel at twice bankful depth. Entrenchment determines whether the flat area next to the stream is a frequent fllod plain, an ancient flood plain, or outside of the flood zone. The entrenchment ratio is used in level 1 Rosgen classification. These values are measured by the Cross-section group.

W:D RATIO
The width/depth ratio is determined by dividing the bankful width by the mean bankful depth. Ratios below 12 are considered low. High ratios may indicate excessive siltation which may result in overheating and loss of habitat. These values are measured by the Cross-section group.

D50
D50 is a measurment of the stream bed material. Recorded as the diameter at which 50% of the particles are that size or smaller. This value is used as an indicator in level 2 Rosgen classification. These values are measured by the Pebble Count group.

SLOPE
Slope is determined by the change in stream surface elevation over a given distance. Recorded as a percent, higher values imply greater scouring of the channel while lower values imply greater sediment deposition. Slope is used in level 1 channel typing. These values are measured by the Cross-section group.

CHANNEL TYPE
Channel Type is given as a combination of values describing channel characteristics (A - G) and substrate characteristics (1 - 6, where 1 is bedrock and 6 is silt or clay).

SINUOSITY
Think of sinuosity as the degree to which the stream channel wanders back and forth. The value of sinuosity is determined by dividing channel length by valley length. This ratio is then used as part of the level 1 Rosgen classification. These values are most easily determined from aerial photos.