Flood Risk Mapping Using LiDAR for Annapolis Royal, Nova Scotia, Canada

Abstract

A significant portion of the Canadian Maritime coastline has been surveyed with airborne Light Detection and Ranging (LiDAR). The purpose of these surveys has been to map the risk of flooding from storm surges and projected long-term sea-level rise from climate change and to include projects in all three Maritime Provinces: Prince Edward Island, New Brunswick, and Nova Scotia. LiDAR provides the required details in order to map the flood inundation from 1 to 2 m storm surge events, which cause coastal flooding in many locations in this region when they occur at high tide levels. The community of Annapolis Royal, Nova Scotia, adjacent to the Bay of Fundy, has been surveyed with LiDAR and a 1 m DEM (Digital Elevation Model) was constructed for the flood inundation mapping. Validation of the LiDAR using survey grade GPS indicates a vertical accuracy better than 30 cm. A benchmark storm, known as the Groundhog Day storm (February 1-3, 1976), was used to assess the flood maps and to illustrate the effects of different sea-level rise projections based on climate change scenarios if it were to re-occur in 100 years time. Near shore bathymetry has been merged with the LiDAR and local wind observations used to model the impact of significant waves during this benchmark storm. Long-term (ca. greater than 30 years) time series of water level observations from across the Bay of Fundy in Saint John, New Brunswick, have been used to estimate return periods of water levels under present and future sea-level rise conditions. Results indicate that under current sea-level rise conditions this storm has a 66 year return period. With a modest relative sea-level (RSL) rise of 80 cm/century this decreases to 44 years and, with a possible upper limit rise of 220 cm/century, this decreases further to 22 years. Due to the uncertainty of climate change scenarios and sea-level rise, flood inundation maps have been constructed at 10 cm increments up to the 9 m contour which represents an upper flood limit estimate in 100 years, based on the highest predicted tide, plus a 2 m storm surge and a RSL of 220 cm/century.

New estimates of potential impacts of sea level rise and coastal floods in Poland

“…Here, a digital elevation model created through airborne laser scanning technology (lidar) was used. DEMs obtained using this method are commonly applied to coastal flood hazard analyses because of their accuracy (Webster 2010). In recent years, the national government launched a large measurement campaign specifically to provide data for flood hazard mapping, which was carried out in the coastal areas between 2010 and 2013 (mainly in 2011).…”

Integrated River and Coastal Hydrodynamic Flood Risk Mapping of the LaHave River Estuary and Town of Bridgewater, Nova Scotia, Canada

“…They have suggested a rise between 0.5 and 1.4 m from 1990 to 2100. This projected increase in global mean sea-level and the fact that many coastal areas of Maritime Canada have been deemed highly susceptible to sea-level rise [36] has led to various studies to produce detailed flood risk maps of coastal communities in Prince Edward Island, New Brunswick, and Nova Scotia [9,[37][38][39]. The most recent set of flood risk maps for coastal communities in Nova Scotia has been produced during the Atlantic Climate Adaptation Solutions (ACAS) project [2,4].…”

Varying Scale and Capability of Envisat ASAR-WSM, TerraSAR-X Scansar and TerraSAR-X Stripmap Data to Assess Urban Flood Situations: A Case Study of the Mekong Delta in Can Tho Province

“…The analyses presented in this paper could be well expanded or continued at greater depth, if the following data were available: digitized houses for the whole province of Can Tho from the same time as the SAR observations, a LIDAR derived DEM-such as undertaken by Webster [37], Terra-SAR-X data in Spotlight mode at 1 m resolution covering the whole province, or additional airborne data etc. However, such a combination of datasets is unfortunately not available for the region.…”