Flood-risk mapping for storm-surge events and sea-level rise using lidar for southeast New Brunswick

Coastal flooding from storm-surge events and sea-level rise is a major issue in Atlantic Canada. Airborne light detection and ranging (lidar) has the spatial density and vertical precision required to map coastal areas at risk of flooding from water levels typically 1–2 m higher than predicted tides during storm surges. In this study, a large section of the New Brunswick coast along Northumberland Strait was surveyed in 2003 and 2004 using two lidar systems. Water levels from a major storm-surge event in January 2000 were surveyed using a global positioning system (GPS) and used as a benchmark for flood-risk maps. Maps of flood depth were also generated for all water levels and used for socioeconomic and ecosystem impact assessment. Flood-risk maps were constructed using standard geographical information system (GIS) processing routines to determine the spatial extent of inundation for a given water level. The high resolution of the lidar digital elevation model (DEM) captured embankments such as raised roadbeds that could prevent flooding inland. Where connectivity was present due to culverts or bridges, the DEM was notched across the roadbed to simulate the connection between the ocean and upstream low-lying areas in the GIS. An automated routine was then used to generate maps of flood extent for water levels at 10 cm increments from 0 to 4 m above mean sea level. Validation of the flood-risk and flood-depth maps for the January 2000 storm-surge water level by field visits indicates that the simulations are generally accurate to within 10–20 cm. The lidar data were also used to evaluate the potential for overtopping and dune erosion on a large coastal spit, La Dune de Bouctouche. This showed a high vulnerability to storm damage for critical habitats on the spit. The lidar-derived maps produced in this study are now available to coastal communities and regional planners for use in the planning process and to assist in development of long-term adaptation strategies.

[1]  André Streilein,et al.  FOR THE VERIFICATION OF COUNTRYWIDE TERRAIN AND SURFACE MODELS , 2003 .

[2]  S. Filin.  Recovery of Systematic Biases in Laser Altimetry Data Using Natural Surfaces , 2003 .

[3]  D. Forbes,et al.  Storms and shoreline retreat in the southern Gulf of St. Lawrence , 2004 .

[4]  M. Bertness,et al.  Anthropogenic modification of New England salt marsh landscapes , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[5]  Tim Webster,et al.  High-Resolution Elevation and Image Data Within the Bay of Fundy Coastal Zone, Nova Scotia, Canada , 2004 .

[6]  M. Bertness,et al.  Rapid shoreward encroachment of salt marsh cordgrass in response to accelerated sea-level rise , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[7]  H. Maas.  Least-Squares Matching with Airborne Laserscanning Data in a TIN Structure , 2000 .

[8]  Tim L. Webster,et al.  LIDAR Validation Using GIS: A Case Study Comparison between Two LIDAR Collection Methods , 2005 .

[9]  D. Forbes,et al.  Defining and Adapting to Coastal Hazards in Atlantic Canada: Facing the Challenge of Rising Sea Levels, Storm Surges, and Shoreline Erosion in a Changing Climate , 2005 .

[10]  N. Mimura,et al.  Coastal Zones and Marine Ecosystems , 2001 .

[11]  J. Shaw,et al.  Sensitivity of the coasts of Canada to sea-level rise , 1998 .

[12]  E. J. Huising,et al.  Errors and accuracy estimates of laser data acquired by various laser scanning systems for topographic applications , 1998 .

[13]  Robert J. Nicholls,et al.  Increasing flood risk and wetland losses due to global sea-level rise: regional and global analyses , 1999 .

[14]  H. Maas.  Methods for measuring height and planimetry discrepancies in airborne laserscanner data , 2002 .

[15]  D. Forbes,et al.  Coastal impacts of climate change and sea-level rise on Prince Edward Island , 2002 .

[16]  K. K. Guy,et al.  Barrier island elevations relevant to potential storm impacts; 2, South Atlantic , 2002 .

[17]  W. Kornus,et al.  STRIP ADJUSTMENT OF LIDAR DATA , 2003 .

[18]  Charles J Vörösmarty,et al.  Widespread decline in hydrological monitoring threatens Pan-Arctic Research , 2002 .

[19]  V. Svetsov,et al.  AIRBORNE LASER STUDY QUANTIFIES EL NINO-INDUCED COASTAL CHANGE , 1999 .

[20]  K. K. Guy,et al.  Barrier island elevations relevant to potential storm impacts; 1, Techniques , 2002 .

[21]  K. Kraus,et al.  Determination of terrain models in wooded areas with airborne laser scanner data , 1998 .

[22]  E. LeDrew,et al.  Remote sensing of aquatic coastal ecosystem processes : science and management applications , 2006 .

[23]  Tim Webster,et al.  AIRBORNE LASER ALTIMETRY FOR PREDICTIVE MODELING OF COASTAL STORM-SURGE FLOODING , 2006 .

[24]  ESTIMATING INTRINSIC ACCURACY OF AIRBORNE LASER DATA WITH LOCAL 3D-OFFSETS , 2003 .

[25]  Chris Hopkinson,et al.  Mapping piping plover (Charadrius melodus melodus) habitat in coastal areas using airborne lidar data , 2007 .

[26]  W. Krabill,et al.  Airborne laser study quantifies El Ni˜o‐induced Coastal Change , 1999 .

[27]  Duncan J. Wingham,et al.  Changes in Sea Level , 2001 .

[28]  M. Hodgson,et al.  An evaluation of LIDAR- and IFSAR-derived digital elevation models in leaf-on conditions with USGS Level 1 and Level 2 DEMs , 2003 .

[29]  R. Holman,et al.  Estimation of Shoreline Position and Change using Airborne Topographic Lidar Data , 2002 .

[30]  J. A. Tullis,et al.  An Evaluation of Lidar-derived Elevation and Terrain Slope in Leaf-off Conditions , 2005 .

[31]  O. V. D. Plassche,et al.  Coastal evolution -- Late Quaternary shoreline morphodynamics , 1995 .

[32]  S. Leatherman,et al.  Sea level and coastal erosion require large‐scale monitoring , 2003 .

[33]  R. Warrick,et al.  Sea level rise , 1990 .

[34]  M. Hodgson,et al.  Accuracy of Airborne Lidar-Derived Elevation: Empirical Assessment and Error Budget , 2004 .

[35]  J. Brock,et al.  Basis and methods of NASA airborne topographic mapper lidar surveys for coastal studies , 2002 .

[36]  Sagi Filin,et al.  Analysis and implementation of a laser strip adjustment model , 2003 .

[37]  J. Hyyppä,et al.  A QUALITY ASSESSMENT OF AIRBORNE LASER SCANNER DATA , 2003 .

[38]  Laura Chasmer,et al.  Vegetation class dependent errors in lidar ground elevation and canopy height estimates in a boreal wetland environment , 2005 .

[39]  J. Shaw,et al.  Salt-marsh aggradation in response to late-Holocene sea-level rise at Amherst Point, Nova Scotia, Canada , 1999 .

[40]  P. Cowell,et al.  Coastal Evolution: Morphodynamics of coastal evolution , 1995 .

[41]  T. M. Lillesand,et al.  Mapping lake water clarity with Landsat images in Wisconsin, U.S.A. , 2004 .

[42]  J. Donnelly,et al.  Coupling instrumental and geological records of sea‐level change: Evidence from southern New England of an increase in the rate of sea‐level rise in the late 19th century , 2004 .

[43]  Tim Webster,et al.  Using topographic lidar to map flood risk from storm-surge events for Charlottetown, Prince Edward Island, Canada , 2004 .

[44]  Hélème Galy,et al.  Using Synthetic Aperture Radar Imagery for Flood Modelling , 2002, Trans. GIS.

[45]  Aloysius Wehr,et al.  Airborne laser scanning—an introduction and overview , 1999 .

[46]  N. Haala,et al.  Capture Andevaluation of Airborne Laser Scanner Data , 1996 .