A number of landslides that occurred during or after a severe storm event on November 15, 2006, caused severe impacts to fish habitat in the Sproat Lake watershed. Fish and fish habitat in an un-named tributary to Two Rivers Arm of Sproat Lake, located at 7.0 km on the Sterling Arm Mainline, was one of the most severely impacted areas. The landslide buried the entire fish bearing portion of the stream, which stretches 500 m upstream from the creek mouth at Sproat Lake (Wright, 2000). It is likely all juvenile fish [coho (Oncorhynchus kisutch) and cutthroat (Oncorhynchus clarki)], spawning sockeye (Oncorhynchus nerka) and coho, and incubating eggs were destroyed by the slide. The greatest impact to fish production was likely the loss of high value sockeye beach spawning habitat surrounding the creek delta. Williams (2006), Askin (2007a), and Campbell and Millard (2007), inspected the slide and concluded that more material is still available upslope and will likely be transported downstream in the future. To protect the critical beach spawning habitat a prescription was developed to trap future materials that could be transported downstream before it reached the critical beach spawning habitat in Sproat Lake. The prescribed works were completed in two phases in 2007.
The trap has been effective in trapping sediment debris since it was constructed in 2007. The sediment storage basin was in filled in the fall of 2007 and cleaned out in the summer of 2008. By mid February of 2010 the basin was filled to the weir crest. To ensure that the upper storage basin continues to function as a sediment and debris trap and continues to provide effective protection for the critical sockeye beach spawning habitat in Sproat Lake a work plan was created and submitted to Forest Investment Account (FIA). The plan submitted was to remove the material stored in the catch basin in preparation for the future storm events The project received approval and funding from FIA to clean out the basin during March of 2010. Approval was granted by DFO to allow works to occur outside the fisheries window.
Wright, Michael C.. 2010. Removal of Sediment stored at the Sediment Storage Basin in an Unnamed Tributary at 7.0 km on the Stirling Mainline, Sproat Lake Watershed, South Island Forest District. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2010MR128
Topic: FLNRORD Research Program
Keywords: Forest, Investment, Account, (FIA), Land, Base, Investment, Program
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