|Citation||Millard, T. 2001. Transport of logging slash and sediment in S5 and S6 streams near Boston Bar, Chilliwack Forest District. Forest Research Technical Report TR-012, Vancouver Forest Region.|
|Abstract/Description or Keywords||Under the Forest Practices Code of British Columbia, a forest
reserve may not be required alongside S5 and S6 streams. S5 and
S6 streams are non-fish streams outside of community watersheds.
In S5 and S6 streams that have harvesting adjacent to
their banks, deposition of additional quantities of woody debris
(logging slash) into the stream may occur. Removal of this logging
slash (usually referred to as stream cleaning) is often done
to prevent increased transport of woody debris and sediment
into fish streams connected to the S5 or S6 stream. This report
investigates the transport of logging slash and sediment in “slashfull”
This study is the second phase of a project initiated in 1999 to
examine the effects of logging slash in channels, and to provide
recommendations to assist in the decision of whether stream
cleaning would be beneficial. The first phase of the project examined
streams near Nitinat Lake, in southwestern Vancouver
Island (Millard, 2000). This second phase of the project examined
streams within the Anderson River watershed, on the east
side of the Fraser Canyon near Boston Bar.
The project has two objectives:
1. To determine how channels respond if logging slash is left in
the stream, and,
2. To identify stream parameters that can be used to predict the
likelihood of channel disturbance and downstream transport
of logging slash and sediment.
Forty-three stream reaches were surveyed, with the data from
42 streams analysed. Most of the streams were logged from 1986
to 1993, with two additional study reaches logged in 1997. Most
of the channels were located in thick, fine-grained till sediments.
The following response variables were measured: size of woody
debris transported, the size of woody debris jams that developed
in the study reach, the size of sediment wedges that developed
in the study reach, and the overall level of disturbance in
the channel. Bankfull channel width was shown to be the most
significant predictor variable for all of these response variables.
The size of sediment transported in the study reach was another
significant predictor variable.
Based on the results of this study and Millard (2000), recommendations
for stream cleaning of S5 and S6 streams were developed.
|Regional Watershed||Lower Fraser|
|Sub-watershed if known|
|Contact Name||Tom Millard|
|Contact Email||[email protected]|