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Research Questions

1914 Hell's Gate Rockslide

2018 Big Bar Rockslide

What is the frequency and magnitude of landslides that likely blocked salmon migration in the Fraser River?

Using LiDAR and surface exposure dating, we will develop a chronology of past landslides in the Fraser Canyon that impacted salmon migration based on location and magnitude.

How have landslides affected the abundance and diversity of Fraser salmon?

We will compare the chronology of landslides in the Fraser Canyon to available sources of historic salmon abundance, life histories, and genetics to assess past landslide impacts on salmon.

What river morphologies create hydraulic barriers?

We will measure channel morphology, flow patterns and velocities, and water level, along the Fraser Canyon to tease apart what conditions create hydraulic barriers to upstream salmon migration.

How do landslides affect environmental conditions that impede salmon migration?

We will explore how landslides such as Big Bar change environmental conditions (e.g., water surface velocities, flow dynamics, channel morphology, suspended sediments) that may affect salmon migration through on-the-river velocimetry and hydraulic modelling.

How is salmon passage failure, delay, or success determined by river conditions or biological characteristics?

Using radio-telemetry stations and hydraulic information, we will examine the fine-scale behavior of radio-tagged salmon past hydraulic barriers and assess how passage success or failure is determined by river conditions (e.g., discharge, water surface velocity) or intrinsic biological characteristics (e.g., species, population, size).

Is there genetic variation that increases the likelihood of passage success?

Through comparing the genetic signatures of salmon that passed and failed to pass the Big Bar Landslide, we will identify genes associated with the ability to successfully pass hydraulic barriers.

Did the genetics of salmon change following the Big Bar Landslide?

We will assess the impact of the Big Bar Landslide on salmon biodiversity by comparing the genomics of salmon before and after landslide from populations upstream and downstream of the landslide site.

Are there other canyons in the Fraser that are susceptible to future landslides?

Using existing data and on-the-river observations of channel morphologies, we will identify canyons that share characteristics (e.g., morphology) with locations of known landslides and may be susceptible to future events.

What is the likelihood of a future landslide damming the Fraser?

We will identify potential landslide sites that could entirely dam the Fraser River using LiDAR and high-resolution imagery to examine unique topographic features and rock types that covary with evidence of past landslides.

What are the geomorphic and biologic consequences of these events?

We will assess how the geomorphic and biologic consequences of a potential future landslide vary with the landslide size and location, pre-existing channel morphology, and affected salmon populations.