Prepared for the Worst: The Importance of Nearshore Hydrographic Mapping Prior to Coastal Disasters

Throughout our nation’s history, disasters have been impacting the Canadian coast. Changes to the climate and continued development could increase their frequency and effects. Episodic events (tsunamis; tropical storms) commonly do not inflict significant damage, but the threat of greater impacts loom, particularly with changes to the climate escalating and increasing offshore petrochemical extraction and exportation. Ongoing coastal processes also steadily alter the coast and nearshore. It is becoming increasingly important to prepare for the possible impacts of accidents (such as a major petroleum spill) and prepare for a rapid response. However, in remote areas there is often no baseline data depicting ecological and habitat conditions. The nearshore environment is particularly complex to map using conventional methods, yet it often serves as the primary line of flood defence for many communities. It is also likely to be the most ecologically fragile region affected by spills and other anthropomorphic actions due to being so rich in aquatic life. Airborne LiDAR bathymetry is a technique for collecting hydrographic survey data that is not adversely impacted by the inefficiencies and hazards associated with shallow water vessel operations. In addition, LiDAR bathymetry data can provide a product that is analogous to sonar back-scatter data (reflectance) which can be used for bottom classification. The technology performs optimally to encompass the water depths of most vessel drafts (typically 20 meters or less) and can also capture adjacent topographic data of the shore. This presentation will discuss the application of airborne LiDAR bathymetry for collecting baseline data in preparation for response to a natural or anthropomorphic disaster.