Scenarios

Altering the bathymetry, coastlines, or physical forcings (such as winds, temperatures and river fluxes) used in SATURN's underlying 3D circulation model allows us to play out "what-if" scenarios, providing insight into how the Columbia River estuary will respond to specific events or conditions. Currently, we have 3 scenarios under development:

• Pre-development: Several data sources, including historical depth and cartographic records, historical vegetation distribution maps and expert knowledge of physical estuarine processes were utilized in the development of a bathymetric grid for the Columbia River as it looked circa 1880. These simulations provide the baseline condition for the Columbia River estuary we need to evaluate both long-term changes in the system, and evaluate the relative impacts of other scenarios
• Post Cascadia Subduction Zone (CSZ) event: Geologic evidence suggests that a significant tectonic event is likely in this region within the next two centuries. This event is likely to produce substantial earthquake and tsunami damages, but the associated subsidence will impose large changes to the Columbia River estuary that may have long-term impacts on the estuarine ecosystem. Subsidence maps produced by Pacific Marine Environmental Laboratories (PMEL) as part of their ongoing tsunami research were used to generate post-CSV event bathymetries for these scenarios. The results illuminate how estuarine processes and habitat may change as a result of subsidence.
• Climate Change: The Intergovernmental Panel on Climate Change (IPCC) 2007 report describes several likely impacts of climate change that will directly influence processes in the Columbia River Estuary. These results, along with original research by collaborators at Oregon State University, are used to produce scenarios for the Columbia River under the influence of climate change.

Salinity Intrusion Length (SIL) comparison between modern conditions (2004) and 3 scenarios: post-CSV event, sealevel rise, and predevelopment conditions (circa 1880). A longer SIL implies higher salinities further up-estuary -- a condition that negatively impacts the quality of estuarine habitat for species like juvenile chinook salmon.