Slash in streams studies

Two studies were conducted on Vancouver Island and east of Boston Bar. The objective of the studies was to identify channels that become disturbed if slash is left in the channel after yarding is completed.

• Channel disturbance corresponds to high water transport potential

On this page:

• Study locations
• Slash in streams studies

Study locations

Vancouver Island study location:

• Near Nitinat Lake, southwest Vancouver Island
• Winter floods from rainstorms
• Mostly rocky terrain, coarse grained soils
• Study referred to as “Nitinat”

Boston Bar study location:

• All streams located within Anderson River basin, east of Boston Bar
• Almost Interior conditions
• Snowmelt dominated floods
• Deep, fine-grained till soils
• Study referred to as “Anderson”

Slash in streams studies

Study methods used in the two locations:

• Select streams that were logged 5 to 15 years ago, with the slash left in the stream
• Inventory amount and types of disturbance
• Collect data on width, depth, gradient, and other variables that may be used to predict disturbance
• Streams are less than 5 m wide

Disturbance includes:

• Large sizes of woody debris are transported
• Large amounts of woody debris are transported
• Frequent and large woody debris jams
• Channel and bank erosion

Severe disturbance

Click image to enlarge.

Variables assessed to predict channel disturbance:

• Channel width and depth
• Gradient
• Channel location
• Channel and bank types
• Size of sediment moving

Study results