Canada-United States Elevation Model Collaboration to Improve Tsunami Inundation Mapping

The tectonic environment, complex physiography, and multi-jurisdictional setting of the Washington State, USA, and southern British Columbia (BC), Canada trans-boundary region poses numerous challenges for scientists modelling coastal inundation. Additional challenges include the lack of a seamless, coastal digital elevation model (DEM) that extends across the international border of Canada and the United States and a common framework for modeling cross-border tsunami inundation.

To address the issue of a cross-border coastal DEM, the DEM development group at the National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Information (NCEI) through the Cooperative Institute for Research in Environmental Sciences (CIRES) collaborated with Ocean Networks Canada (ONC) at the University of Victoria (UVic), BC in providing instruction on coastal DEM development for the Semiahmoo First Nation. The two-part, 8-day DEM workshop was hosted by ONC at UVic for a diverse assortment of geospatial specialists and engineers from the public and private sectors 23-27 September and 21-23 October 2019. This workshop was part of the West Coast demonstration study of the Canadian Safety and Security Program (CSSP) Coastal Flood Mitigation Canada Project, led by Natural Resources Canada (NRCan). The output of the workshop was a coastal DEM for the Semiahmoo First Nation, which expanded in scope to include all of Metro Vancouver, BC, and a portion of northern Washington State. Documentation of the workshop proceedings are also informing Canadian best-practices for coastal DEM development.

The Semiahmoo First Nation, a community that spans the international border, has expressed concern on conflicting information about tsunami hazards and risks from the Canadian and United States federal governments. Our collaborative project between Canadian and American scientists and the Semiahmoo First Nation provides a unique opportunity to co-create knowledge on coastal flood risks in the cross-border region. Ongoing collaboration between NOAA, ONC, NRCan, and the University of Washington is focusing on the coordination of tsunami modeling efforts including the establishment of consistent tsunami source events, DEM vertical datums, and spatial resolutions.