Channel Disturbance Index
NetMap's Watershed Assessment
Watershed Attribute: An index of channel disturbance provides insights into the degree of fluvial and hillslope dynamics in individual channel segments. The disturbance index may be useful in planning restoration or monitoring.
Data Types: Line (stream layer)
Field Name: CDI; Channel Disturbance Index
Units: numeric (0-1), a product of the geometric mean model
NetMap Level 1 Module/Tool: Aquatic Habitat Module/Channel Disturbance Index
Model Description:
The index is created using the same (geometric mean) modeling structure used in habitat intrinsic potential modeling. Disturances can include landslide erosion or debris flow impacts. It may also refer to changes in valley width or floodplain width that would indicate increases in sediment storage. Predicted sedimentation is another disturbance etc.
NetMap’s Channel Disturbance tool predicts the most likely locations within a river network that would have the highest potential for disturbance related to sediment and wood supply, transport, and storage (and hillslope influences, such as landslides and debris flows).
In the Watershed Assessment Package - Aquatic Habitats, the attributes used in calculating the channel disturbance index include: 1) channel gradient, 2) floodplain or valley width transitions (confined to unconfined, unconfined to confined), 3) tributary confluence effects, including debris flows, 4) hillslope erosion potential and 5) floodplain width.
