Gwa-Yee Village is located in the Kingcome River valley, approximately 7 km upstream from the river estuary. Following a very large flood in September of 2010 that resulted in the emergency evacuation of all residents, NHC was selected by the Dzawada’enuxw First Nation (DFN) to conduct an integrated study of river flood and erosion hazards in the Kingcome River valley.

A traditional approach to flood hazard assessment that considers only flood height was clearly not appropriate for Kingcome River, which has a history of rapid channel migration, lateral erosion, and potentially bed aggradation. NHC took a broad-based approach to evaluating the suite of hazards that Gwa-Yee Village is exposed to, including an assessment of the potential for a glacier lake outburst flood (GLOF) emanating from the headwaters of the watershed and an analysis of sea-level rise that was incorporated into the numerical flood model.

The collection of data pertinent to the study formed a significant part of the project. Topographic and hydrographic data were collected by NHC surveyors with support from Chatwin Engineering. NHC coordinated with Eagle Mapping Ltd., who supplied LiDAR data and orthophotography. Possibly the greatest short-term benefit to the community that arose from this project was the installation of a flood monitoring system that allows for remote access to the data for residents as well as flood forecasters and emergency response agencies.

As part of the final project tasks, various flood and erosion hazard mitigation strategies will be outlined to provide options for the DFN to include in their longterm community planning. These options will consider the full range of hazards in the context of cost versus the level of protection that they can afford to the village.