The Chilako River, a significant tributary of the Nechako River, lies about 15 kilometres west of Prince George in central British Columbia. This 6th-order river is an essential salmon spawning habitat, but its ecosystems have undergone severe alterations due to human activities and natural disturbances.
Key Environmental Concerns:
Ecosystem Alterations: Agriculture, forest harvesting, forest fires, and the Mountain Pine beetle infestation have dramatically changed the natural landscape of the river and surrounding areas.
Riparian Vegetation Decline: Land use practices have led to a significant reduction in riparian vegetation. This decline, linked to increasing bank erosion and sediment transport, directly affects the river's stability (Miles & Allegretto, 2017).
To counteract the environmental challenges faced by the Chilako River, numerous bank restoration projects have been undertaken. These initiatives are vital in reversing the effects of erosion and habitat degradation that have been exacerbated by both human activities and natural disturbances.
One of the key strategies in these restoration efforts is re-sloping the eroded banks. This technique involves reshaping the riverbanks to a more gradual slope, which helps minimize further undercutting caused by the river's flow. By reducing the steepness of the banks, the risk of soil erosion is significantly lowered, contributing to the overall stability of the river's edge.
Another crucial aspect of the restoration process is the replanting of riparian vegetation. Species such as aspen and willow are particularly favoured in these projects due to their root system's ability to stabilize the soil effectively. Additionally, these plants provide essential shading along the riverbanks, playing a critical role in regulating water temperatures. This shading is not only beneficial for the river's ecosystem balance but is also crucial for the survival and health of the salmon populations, which are sensitive to temperature changes.
Furthermore, the placement of large woody debris along the banks forms an integral part of the restoration strategy. These structures serve multiple purposes: they help divert the river's flow away from the banks, reducing erosion, and they also create natural habitats for fish and invertebrates. This addition of woody debris not only aids in stabilizing the riverbanks but also enhances the ecological diversity of the river, providing shelter and breeding grounds for various aquatic species.
An example of these methods is provided below with drone imagery from 2016 and drone imagery in 2017 after restoration.
Below are four other restoration sites along the Chilako River. Zoom in and investigate the different stabilization methods used.
Endangered Fish Populations: The fish populations within the Chilako watershed are endangered, impacting the indigenous communities' fishing rights (Forsite, 2019).
Documentation Gaps: A major challenge in restoration efforts is the lack of recorded pre-impact conditions, complicating recovery planning.
Diverse Impact Factors: The Chilako watershed has experienced ecological shifts due to various factors, including climate change, agriculture, forestry, flooding, and wildfires.
Biodiversity Loss: Studies indicate a loss of biodiversity, with observable effects like catastrophic flooding, erosion, and loss of riparian vegetation (Forsite, 2019).
Human Activities Impact: Activities such as cattle grazing, road development, timber harvesting, and forage production have contributed to habitat degradation and increased sediment in the water.
Wildlife Impact: The removal of vegetation and increased erosion have adversely affected the local wildlife.
Despite these challenges, various restoration and conservation projects are underway. Stream bank stabilization initiatives address erosion and vegetation loss. Additionally, about 12% of the watershed area is under various park designations, including provincial parks and Old Growth Management Areas, to protect sensitive habitats (Forsite, 2019). However, ongoing disturbances especially in valley flats near the river, remain a concern. Past research has outlined the current state of the Chilako River corridor, but more comprehensive studies are needed to fill existing information gaps and guide recovery strategies. Unique research opportunities exist in the headwater streams, which have experienced differing levels of disturbance. Comparisons between these areas and those near Tatuk Lake, which remain undisturbed, could provide valuable insights into the land use impacts and the ecosystem's resilience.