Ministry of Environment
EcoCat:The Ecological Reports Catalogue
EcoCat Image
 

Report: Assessment and Development of Preliminary Design Options for Channel Improvements in Cowichan River Mainstem, With Emphasis Upstream of Skutz Falls

Report Documents
 
Map Plotfiles
  • No files of this type available
 
Data Files
  • No files of this type available
 
Digital Map Files
  • No files of this type available
 
Image Document
  • No files of this type available
 
Video Files
  • No files of this type available
 
All Documents

  • No files available

Contact

  • If you have any questions on the information presented, or require additional report data or attachments, please contact the Report Contact

 
Significant erosion sites have also been identified further upstream above Skutz Falls. An assessment of these erosion sites was completed in 2008 (Gaboury et al. 2008). In the assessment, the composition of the eroding banks, the mechanism of bank failure, the relative rate of bank erosion, and the existing or potential risk to downstream fish habitat was investigated and evaluated. The recommendations from the report provided the basis for focused assessments that have followed in 2009.

Author:  Marc Gaboury; LGL Limited environmental research associates. Prepared for BC Conservation Foundation

Date Published:  Jan 2010

Report ID:  23901

Audience:  Government and Public

The impact of fine sediments on salmonid egg incubation habitat in the Cowichan River is an ongoing concern among members of the Cowichan Stewardship Roundtable. High inputs of fine sediments, typically from excessive bank erosion, may infiltrate the interstices of the riverbed spawning gravel and reduce egg-to-fry survivals. Although sediment inputs from naturally eroding banks are apparent along the mainstem, several sites stand out as having larger areas of fine sediments and which are or have the potential to be significant sources of fine sediments to the river. For example, Stoltz Bluff has been identified as the most significant single source of fine sediments to the river (LGL and KWL 2005; KWL 2005). Rehabilitation measures were constructed at Stoltz Bluff in 2006 to stabilize the toe of the Bluff thereby reducing sediment inputs from this chronic erosion site. Significant erosion sites have also been identified further upstream above Skutz Falls. An assessment of these erosion sites was completed in 2008 (Gaboury et al. 2008). In the assessment, the composition of the eroding banks, the mechanism of bank failure, the relative rate of bank erosion, and the existing or potential risk to downstream fish habitat was investigated and evaluated. The recommendations from the report provided the basis for focused assessments that have followed in 2009. The recommendations included: 1. Investigate rehabilitation approaches that are less intrusive and less costly near Sites 5 & 7 2. Implement two activities at Site 9: a. characterize the unstable bluff to obtain a better understanding of the scale and potential impact of the hazard; b. explore rehabilitation opportunities for river re-alignment by moving the main river channel to the east (left bank) and away from the toe of the bluff; 3. Investigate the feasibility, cost and benefits of re-aligning the river near Site 8. This memorandum addresses the recommendations 1, 2b and 3 from Gaboury et al. (2008) and presents the results of assessments that focused on identifying opportunities for implementing rehabilitation measures at sites where the existing or potential risk of negatively affecting fish and fish habitat was considered high. The memo also presents conceptual rehabilitation designs to address these high risk sites in the Block 51 area. For this project, the area under consideration is restricted to the Cowichan River mainstem and between Site 5 and Site 9 (Broadway Run). This project was co-funded by Living Rivers-Georgia Basin/Vancouver Island (2006-11), a program of the BC Living Rivers Trust Fund.

Report Type
  Fish and Aquatic Habitat Information
 
Subject
  Fish and Fish Habitat - Channel Assessment
  Fish and Fish Habitat - Habitat and Stream Assessment
  Fish and Fish Habitat - Restoration
  Fish Species - Brown Trout - Salmo trutta
  Fish Species - Chinook Salmon - Oncorhynchus tshawytscha
  Fish Species - Chum Salmon - Oncorhynchus keta
  Fish Species - Coastal Cutthroat Trout - O. clarki clarki
  Fish Species - Coho Salmon - Oncorhynchus kisutch
  Fish Species - Cutthroat Trout (General) - Oncorhynchus clarki
  Fish Species - Dolly Varden Char - Salvelinus malma
  Fish Species - Rainbow Trout - Oncorhynchus mykiss
  Fish Species - Steelhead - Oncorhynchus mykiss
  Region - Vancouver Island
  Watershed Groups - 920 - Vancouver Island (East) Rivers
  Water Information - Channel Monitoring Surveys
  Water Information - Channel Morphology
  Water Information - Restoration
  Water Information - Water Quality
 


Warranty Disclaimer

This information is provided as a public service by the Government of British Columbia, Box 9411, Victoria, British Columbia, Canada V8W 9V1. This Web site and all of the information it contains are provided "as is" without warranty of any kind, whether express or implied. All implied warranties, including, without limitation, implied warranties of merchantability, fitness for a particular purpose, and non-infringement, are hereby expressly disclaimed. Limitation of Liabilities Under no circumstances will the Government of British Columbia be liable to any person or business entity for any direct, indirect, special, incidental, consequential, or other damages based on any use of this Web site or any other Web site to which this site is linked, including, without limitation, any lost profits, business interruption, or loss of programs or information, even if the Government of British Columbia has been specifically advised of the possibility of such damages.


 

COPYRIGHT | DISCLAIMER | PRIVACY | ACCESSIBILITY