Watershed Restoration Program using Large Sediment Traps on Slope Failure

COFFEE CREEK PROJECT

Location: Nelson, British Columbia

Client: Meadow Creek Cedar Ltd.

Objective: To prevent sediment delivery to Coffee Creek while establishing vegetation within riparian areas.

Mitigation of Major Sediment Source

Coffee Creek is located in southeast British Columbia near the town of Nelson. In November 1999, a major rain on snow event occurred which caused a number of debris slides and debris flows in the Coffee Creek watershed and a debris flood in the Coffee Creek channel. Some of the slides were related to logging and drainage diversion on roads and some were natural.

As part of the Restoration Plan KL 18, prepared by Meadow Creek Cedar Ltd., with funding from Forest Renewal BC (Zimmer and Putt, 2001), a program for watershed restoration was outlined. The program included mitigation of major sediment sources in the Coffee Creek drainage.

The focus of the proposed rehabilitation work was to help stabilize and re-vegetate the major point sediment sources. The treatment was implemented in the fall of 2001. Local materials were used to build sediment traps, and a grass/legume mix, together with alder (Alnus incana ssp. tenuifolia) and black cottonwood (Populus balsamifera ssp. trichocarpa) plugs, were planted to speed up re-vegetation of the sites. Removal of trees from the slide headwall was carried out to reduce the risk of further headwall failure and for safety reasons. The sites were then monitored in the summer of 2003 and functioning sediment traps were observed.