Sea level rise increases coastal flooding in many areas of Canada. The Canadian Extreme Water Level Adaptation tool has been developed to accommodate sea level rise. The infrastructure needs to be built higher in order to reduce the risk of flooding. The vertical allowance is the recommended height that the infrastructure to be raised in future years relative to year 2010. The vertical allowance depends on (1) statistics of historical storm surge and tides, and (2) the best estimate and associated uncertainty of future sea level rise. The vertical allowance preserves the frequency of flooding events at some future time under uncertain sea level rise. Vertical allowances are provided for scenarios based on the fifth assessment report (AR5) of IPCC for the period of 2020-2100 and the sixth assessment report (AR6) of IPCC for the period of 2020-2150. Cite this data as: Zhai, L., Greenan, B., Perrie, W. Data of: Vertical allowance gridded dataset for Canada. Published: February 2024. Ocean Ecosystems Science Division, Fisheries and Oceans Canada, Dartmouth, N.S. https://open.canada.ca/data/en/dataset/5c164079-9785-42fa-8fa5-d886ccbae3b3

Extreme water level along the marine coastline is a result of a combination of storm surge, tides, and ocean waves. Future projections of climate change in the marine environment indicate that rising sea level and declining sea ice will cause changes in extreme water levels, which will impact Canada's coastlines and the infrastructure in these areas. Understanding these changes is essential for developing adaptation strategies that can minimize the harmful effects that may result. CAN-EWLAT is a science-based planning tool for climate change adaptation of coastal infrastructure related to future water-level extremes and changes in wave climate. The tool includes two main components: 1) vertical allowance and 2) wave climate. CAN-EWLAT was developed primarily for DFO Small Craft Harbours (SCH) locations, but it should prove useful for coastal planners dealing with infrastructure along Canada’s ocean coastlines. Cite this data as: Greenan B. Canadian Extreme Water Level Adaptation Tool (CAN-EWLAT) Published June 2022. Oceans Ecosystems Science Division, Fisheries and Oceans Canada, Dartmouth, N.S.