Abstract
Siwash Island is a tidal marsh situated at the southern end of the Widgeon Marsh Regional Park Reserve, Coquitlam, British Columbia (BC). The numerical model MarshMorpho2D was used to depict the evolution of marsh under various scenarios of sea level rise (SLR), suspended sediment concentration (SSC), and tidal range (TR) over the next 80 years. Changes in SLR and TR substantially impact the island's morphology. Higher TR and SLR cause higher inundation and erosion rate, resulting in loss of vegetation, elevation, and habitat across the island. The model projection indicates that Siwash Island is likely to submerge within the next 80 years. The MarshMorpho2D model provides insights for policymakers and conservationists to develop adaptive strategies to mitigate the effect of SLR on coastal ecosystems.