FSWP Coquihalla (Ladner Creek) Side-Channel – Phase II

Historic and ongoing anthropogenic activities have negatively impacted the aquatic ecosystem of the Coquihalla River and its tributaries; this is mainly due to the infrastructure related to the KVR railway, Coquihalla Highway, and a gas utility pipeline, as well as years of poor timber harvesting practices. River bank armouring to protect this infrastructure has confined the river and prevented river meandering, reducing natural hydraulic conditions from creating diverse fish habitat. The Coquihalla River was once a high producer of summer-run steelhead, and in fact was once a premier recreational steelhead angling stream. It is unique in the sense that it is one of only two Fraser Valley river systems home to a native population of summer-run steelhead trout. This stock has declined drastically over past decades due to poor freshwater habitat and reduced ocean conditions. Improving habitat capacity will yield greater smolt abundance throughout the watershed. The head of the side-channel project is located approximately 1.5 km from the confluence of Ladner Creek and the Coquihalla River. Phase I of the Ladner Creek side-channel project was conducted in 2008 and included the construction of a natural cut intake, and rudimentary excavation of the 740 m length side-channel, with only minor habitat complexing. In Phase II (2009-2010) the objective was to increase habitat complexity, optimize flow conditions, and protect the channel from mainstem flood flows. The wetted channel was complexed with woody debris (50) and boulders (100), and new deep pond habitat (5) was created. To improve flows throughout the channel, substrate at the intake was removed, bank failure was remediated, and a log drop structure downstream of the intake was modified to improve flow. By engaging volunteers, boulder riffles, and log weirs were re-configured to provide free access to juveniles throughout the entire channel. A 75m length cobble/boulder protective berm was constructed between the mainstem and side channel.