McIntyre Creek Streambank Stabilization

McIntyre Creek is an important Chinook salmon rearing stream within the City of Whitehorse. This creek flows directly into the Yukon River and is culturally important to the Ta’an Kwäch’än Council (TKC); it is part of TKC’s Traditional Territory and an important fish camp was present at the mouth of the creek in the past. It is a documented Chinook salmon rearing channel, and a considerable number of juvenile Chinook have been captured in the lower reaches of this creek below Mountain View Drive, during recent fish sampling works (EDI 2011). In the 1940’s the U.S. Army initiated the construction of a landfill on the escarpment above the lower reaches of McIntyre Creek. This landfill was operated by the army through the 1940’s, and then transferred to the City of Whitehorse and operated as the municipal landfill until it was closed by the Yukon Water Board in 1975. In 1968, a large volume of dump refuse slid down the escarpment and into McIntyre Creek. Subsequently, with the construction of a berm, the affected portion of McIntyre Creek was re-routed to isolate it from its original stream channel which was extensively filled with debris at bottom of the escarpment. With the exception of the berm construction in 1968, large scale clean-up and remediation of the landfill and associated riparian area of McIntyre Creek did not occur until TKC initiated these work in 2004. In 2005, TKC constructed a new earth berm in the riparian area of lower McIntyre Creek. The construction of this berm was funded by the Yukon River Panel R&E fund (CRE-53-06) and was constructed as the first stage of TKC’s clean-up of the former landfill. The purpose of the berm was to prevent the creek from eroding into the area of the former creek channel that was isolated in 1968.
Recent visits to the site have indicated that several areas of McIntyre Creek near the former dumpsite are actively eroding, and may by-pass the berm structure that was installed in 2005. The stream bank in this area is steep and is eroding too quickly to allow for the establishment of riparian vegetation. Although the
majority of the surface waste material was removed during TKC’s clean-up operations, if the creek erodes into the former dumpsite area, remaining waste material could be exposed and transported downstream into the Yukon River. It is felt that this potential issue could be avoided by installing some stream bank stabilization features to deflect flow away from this area. As such, TKC proposes to install small flow deflection structures along the eroding banks of McIntyre Creek, to slow the rate of erosion in the area of concern.