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Slocan River Preliminary Side Channel Assessment: 2010
Feb. 2011 Prepared by Peter J. Corbett, RPBio
Side channels are a critical component to rainbow trout (Oncorhynchus mykiss) ecology and have become increasingly rare in human-modified flood plains. An initial inventory identified over 80 side channels throughout the Slocan River. Some of these were relatively minor in nature; small channels created by gravel bars. Many were historic. Only 11 identified as fully functioning, meaning that they provided trout habitat for all 3 seasonal habitat uses: spawning, spring refuges, and summer/fall habitat. There were a total of 45 significant channels identified throughout the river. From these 10 were selected for further field investigations; 3 fully functioning channels to act as benchmarks and 7 that have potential for restoration.
Biophysical data was collected throughout the year. Trout use was highest in the functioning side channels and was also proportionally higher than in their adjacent mainstem reaches. The 7 potential sites all shared similar biophysical characteristics with the benchmark sites, with the exception that stream discharge was much lower. The potential to increase rainbow trout production through side channel restoration on the Slocan River is evident and technical challenges should be explored to realize this goal.
Slocan River Riparian Restoration Monitoring: A Year Two Review of the 2005 Restoration Projects
Feb. 2008 Prepared by Peter J. Corbett, RPBio
As a component of the Brilliant Expansion Power Corporation’s (BEPC) Fish Compensation Program, the Slocan Valley Riparian Restoration Program was initiated. This program is designed to address riparian degradation on privately held land that if restored could contribute to the creation of habitat that could help achieve the goal of enhancing the rainbow trout (Oncorhynchus mykiss) population in the Slocan River. Through a public application for proposals, BEPC awarded 8 grants for riparian restoration projects to be undertaken in the fall of 2005.
In 2007, these initial 8 projects were reviewed. Measurable improvements were only observed on 4 of the 8 projects. These projects are Cross/Clarke, Dupont, Egan and the Trozzo site of the Slocan Valley Heritage Trail Society (SVHTS). The Blunderfield project has seen some significant changes from 2005 but most of these were brought about through the necessity to restore damages created by the property owner and would be difficult to say if the current conditions is an improvement prior to the landowner altering the site.
The number of observed trout observed at all the sites combined has increased from 5 trout in 2005 to 11 trout in 2007. The same increases have been observed elsewhere in the river and would be difficult to attribute these increases with the efforts of the Riparian Restoration Program.
Slocan River Riparian Restoration Monitoring: 2006
Feb. 2007 Prepared by Peter J. Corbett, RPBio
As a component of the Brilliant Expansion Power Corporation’s (BEPC) compensation efforts, the Slocan Valley Riparian Restoration Program was initiated. This program is designed to address riparian degradation on privately held land that if restored could contribute to the creation of habitat that could support a portion of the goal to restore 250 additional rainbow trout (Oncorhynchus mykiss) to the Slocan River. Through a public application for proposals, BEPC awarded 8 grants for riparian restoration projects to be undertaken in 2006.
As a component of the restoration program, pre and post monitoring of the restoration projects is to be undertaken to determine success of the program and will provide valuable insight into effective restoration prescriptions and techniques.
To this end, Level I Riparian Assessment Plots were established for all 8 projects. In addition, a stream bank assessment was conducted at each site as a baseline to determine changes at the riparian/stream interface and was complimented by fish assessments along the stream bank using underwater survey techniques.
All of the project sites have experienced riparian degradation and ecological function would be considered low to moderate. Rainbow trout were observed at only 1 of the 8 project sites, reflecting the potential of these projects to benefit trout and their habitat.
2005 Trout Population Index Site
June 2006 Prepared by Peter J. Corbett, RPBio
Monitoring of the Slocan River rainbow trout (Oncorhynchus mykiss) population began in 1985. In 1993 the river was closed to angling based on previous assessments that demonstrated the population was in severe decline. Since the closure, the population has increased but still displays a high variability in population size and structure. This variability may be explained in part by the variability of summer water temperatures, whereby in certain years a temperature threshold is exceeded causing trout mortality and/or a reduction in fitness. The one consistency in the data is that the Lemon Creek index site produces a significantly greater number of trout in all age/size classes than any of the other index sites.