Tim Webster - Academia.edu (original) (raw)
Papers by Tim Webster
for salt marshes near the Cornwallis Estuary, Nova Scotia, and Fort Beausejour, New Brunswick, re... more for salt marshes near the Cornwallis Estuary, Nova Scotia, and Fort Beausejour, New Brunswick, respectively. The data were used to develop digital elevation models (DEM) of the two sites with a resolution of 1 metre and a vertical precision of +/-15 and +/-30 cm depending on the system used. Aerial photographs were also obtained, orthorectifi ed and mosaicked. These basins have a high tidal range which, at low tide, allowed a large portion of the inter-tidal zone to be surveyed, including tidal fl ats and salt marshes.
Journal of Marine Science and Engineering, 2015
Geomatica
This paper outlines a new software tool, Water Modeler, which is a component of a Coastal Zone De... more This paper outlines a new software tool, Water Modeler, which is a component of a Coastal Zone Decision Support System. The Water Modeler can analyze a time series of water-level records (tide gauge observations) to determine the risk associated with a high water level from a storm surge event or long-term sea-level rise. The new tool has been applied in two case studies in Nova Scotia, Canada, where coastal flood-risk maps have been derived from high-resolution LiDAR digital elevation models. The first case study is for Annapolis Royal on the Bay of Fundy side of the province, while the second looks at the Kingsburg area of Lunenburg County on the Atlantic shore. The Saint John, New Brunswick, and Halifax tide gauge records were used for Annapolis Royal and Kingsburg, respectively, in the Water Modeler to examine the risks of coastal flooding. The Groundhog Day storm of 1976, which caused coastal flooding around the Bay of Fundy, was used as a benchmark for Annapolis Royal. At curr...
Wetlands Ecology and Management
Much of the coast in the Canadian Maritimes is susceptible to erosion and flooding from storm-sur... more Much of the coast in the Canadian Maritimes is susceptible to erosion and flooding from storm-surge events and long-term sea-level rise. In recent years significant damage has occurred during storms in both urban and rural areas of the region. LiDAR technology has been employed to develop high-resolution digital elevation models (DEMs) as a basis for production of flood-risk maps. These
Research Monographs in GIS, 2004
Remote Sensing and Digital Image Processing, 2006
Using a LIDAR-Derived DEM FIGURE 7 Close-up of the three flood extents for the waterfront area of... more Using a LIDAR-Derived DEM FIGURE 7 Close-up of the three flood extents for the waterfront area of Charlottetown. The image is a color shaded relief of the DSM.
Canadian vessels equipped with multibeam bathymetry systems are in high demand by the Canadian Hy... more Canadian vessels equipped with multibeam bathymetry systems are in high demand by the Canadian Hydrographic Service (CHS) and by researchers from the Geological Survey of Canada (GSC). For several years, survey time for geological mapping was allocated in relatively small blocks of 10-20 days to provide as many applicants as possible the opportunity to collect multibeam bathymetry data. The resulting
Water, 2014
ABSTRACT The contamination of shellfish harvesting areas by fecal bacteria in the Annapolis Basin... more ABSTRACT The contamination of shellfish harvesting areas by fecal bacteria in the Annapolis Basin of Nova Scotia, Canada, is a recurring problem which has consequences for industry, government, and local communities. This study contributes to the development of an integrated water quality forecasting system to improve the efficiency and effectiveness of industry management. The proposed integrated forecasting framework is composed of a database containing contamination sources, hydrodynamics of the Annapolis Basin, Escherichia coli (E. coli) loadings and watershed hydrology scenarios, coupled with environmental conditions of the region (e. g., temperature, precipitation, evaporation, and ultraviolet light). For integration into this framework, this study presents a viable methodology for assessing the contribution of fecal bacteria originating from a watershed. The proposed methodology investigated the application of high resolution remote sensing, coupled with the commercially available product, MIKE 11, to monitor watershed land use and its impact on water quality. Remote sensing proved to be an extremely useful tool in the identification of sources of fecal bacteria contamination, as well as the detection of land use change over time. Validation of the MIKE 11 model produced very good agreement (R-2 = 0.88, E = 0.85) between predicted and observed river flows, while model calibration of E. coli concentrations showed fair agreement (R-2 = 0.51 and E = 0.38) between predicted and observed values. A proper evaluation of the MIKE 11 model was constrained due to limited water sampling. However, the model was very effective in predicting times of high contamination for use in the integrated forecasting framework, especially during substantial precipitation events.
Wetlands Ecology and Management, 2013
ABSTRACT Salt marshes exhibit striking vegetation zonation corresponding to spatially variable el... more ABSTRACT Salt marshes exhibit striking vegetation zonation corresponding to spatially variable elevation gradients which dictate their frequency of inundation by the tides. The salt marshes in the upper Bay of Fundy, a dynamic hypertidal system, are of considerable interest due to increasing recognition of salt marsh ecosystem values and the extent of prior conversion of salt marshes to agricultural lands, much of which are no longer in use. To determine the suitability of two potential restoration sites at Beausejour Marsh in New Brunswick, Canada, geomatics technologies and techniques were used to assess vegetation and elevation patterns in an adjacent reference salt marsh and the proposed restoration sites. Light detection and ranging digital elevation models (DEMs) were created for the reference marsh and the restoration sites in both the spring (leaf-off) and late summer (leaf-on, maximum biomass) periods. Aerial photographs and Quickbird multispectral imagery were used to visually interpret vegetation zones on the reference marsh and were field validated using vegetation characteristics from quadrats referenced with differential GPS. Elevation limits of the salt marsh vegetation zones were extracted from the DEM of the reference marsh and applied to the DEM of the restoration sites to determine the percentage area of each site that would be immediately suitable for new salt marsh growth. Of the two restoration sites assessed, one had experienced significant subsidence since dyking; only about 40 % of the site area was determined to be of sufficient elevation for immediate vegetation colonization. The second site, while more than 88 % suitable, would require the installation of a large dyke on the landward side of the restoration site to prevent flooding of adjacent lands. This study provides essential high resolution elevation and vegetation zonation data for use in restoration site assessments, and highlights the usefulness of applied geomatics in the salt marsh restoration planning process.
Water, 2014
Bridgewater, Nova Scotia, is located 20 km inland from the mouth of the LaHave River estuary on t... more Bridgewater, Nova Scotia, is located 20 km inland from the mouth of the LaHave River estuary on the Atlantic Coast of Canada. Bridgewater is at risk of flooding due to the combined effects of river runoff and a storm surge on top of high tide. Projected increases in sea-level and possible increased river runoff with climate change increase the risk of future flooding. A set of river and ocean water level simulations were carried out to determine the risk of flooding to Bridgewater today and in the future under climate change. The hydrodynamic simulation developed incorporates return periods of a time series of river discharge measurements for the LaHave watershed, ocean water dynamics at the mouth of the river under normal tidal conditions and with two levels of storm surge, near shore and river bathymetry, as well as high precision topographic lidar derived ground elevations and survey grade GPS. The study was supported by data from two tide gauge sensors, and qualitative evidence provided by the community such as historical flood levels and photographs. Results show that areas upstream of the town are vulnerable to large discharge events of the LaHave River. The downtown waterfront and infrastructure are not susceptible to fluvial flooding, but is vulnerable to sea-level rise and storm surge flooding.
Water, Air, & Soil Pollution, 2011
Sediment cores were analysed from four coastal wetland sites within the Minas Basin, Bay of Fundy... more Sediment cores were analysed from four coastal wetland sites within the Minas Basin, Bay of Fundy to compare mercury speciation and sediment characteristics. The coastal wetland sediments were low in total mercury (mean=17.4± 9.9 ng g −1 ); however, MeHg concentration was 92 times higher (mean of 249 pg g −1 ) than intertidal mudflat sediment (mean of 2.7 pg g −1 ). Total mercury concentrations in intertidal mudflat cores were also low (0.5-23.7 ng g −1 ) and correlated (Pearson correlation=0.98; p<0.01) with % organic
Journal of Coastal Research, 2011
CROWELL, N.; WEBSTER, T., and O'Driscoll, N.J., 2011. GIS modelling of intertidal wetland exposur... more CROWELL, N.; WEBSTER, T., and O'Driscoll, N.J., 2011. GIS modelling of intertidal wetland exposure characteristics.
Geocarto International, 2001
... Several basins developed in the Late Devonian - Early Carboniferous— including the Kennetcook... more ... Several basins developed in the Late Devonian - Early Carboniferous— including the Kennetcook, Shubenacadie (Giles and Boehner 1982) and St. Mary's Basins (Webster, 1996). ... 5). The structural deformation is localized within the basins - for example the Walton area (Fig. ...
Estuaries and Coasts, 2012
Analysis of dissolved organic matter (DOM) concentration and composition is essential to quantify... more Analysis of dissolved organic matter (DOM) concentration and composition is essential to quantifying biological and chemical oxygen demand and atmosphereocean heat flux exchange in natural waters. However, manual water sampling is costly and time consuming over large areas. The purpose of this research was to analyze the applicability of airborne laser-induced fluorescence light detection and ranging (LiDAR) for the detection of DOM in estuarine ecosystems impacted by agriculture. A fluorescence LiDAR system (Airborne Marine) (FLS-AM) was used to assess the DOM concentration of the Annapolis River and Basin, Nova Scotia, Canada, as well as three rivers and their estuaries in Prince Edward Island, Canada. Two FLS-AM flight missions were conducted in the summers of 2008 and 2009 and the resulting datasets were compared with spectral fluorescence signature (SFS DOM) and dissolved organic carbon (DOC) analysis of in situ water samples. Significant positive correlations were found at five of seven sites between the FLS-AM DOM and SFS DOM relationship which indicates that the FLS-AM sensor is a good surrogate for traditional sample collection of DOM data in estuaries in this region. Positive correlations were also found at all sites between FLS-AM DOM values and DOC. FLS-AM DOM patterns show that DOM values are significantly higher in rivers and estuaries that drain watersheds which are heavily impacted by agricultural practices. The results of this study show that the FLS-AM can be used efficiently as a general indicator for how estuaries are affected by runoff from agricultural watersheds in real time and thus reduce the requirement for traditional water sample collection and laboratory analysis methods.
Computers & Geosciences, 2006
High-resolution elevation surveys utilizing light detection and ranging (LIDAR) are becoming avai... more High-resolution elevation surveys utilizing light detection and ranging (LIDAR) are becoming available to the geoscience community to derive high-resolution DEMs that are used in a variety of application areas. However, prior to the application of these data to geomorphic interpretation, extensive validation procedures should be employed. The vertical accuracy specification for the survey called for heights to be within an average of 15 cm of measured GPS heights and 95% of the data to be within 30 cm. Two different LIDAR systems and collection methods were employed to collect data for the study area located in the Mesozoic Fundy Basin in eastern Canada. High-precision GPS surveys were conducted to measure the ground elevations in open areas and a traditional topographic survey was carried out in order to assess the accuracy of the laser data under the forest canopy. The LIDAR and validation data were integrated into a GIS where an automated procedure was developed that allows the user to specify a search radius out from the validation points in order to compare proximal LIDAR points. This procedure facilitates examining the LIDAR points and the validation data to determine if there are any systematic biases between flight lines in the LIDAR data. The results of the validation analysis of the two LIDAR methods and a description of the automated procedure are presented in this paper. r
Canadian Journal of Remote Sensing, 2004
As part of a recent project to determine coastal impacts of climate change and sea-level rise on ... more As part of a recent project to determine coastal impacts of climate change and sea-level rise on Prince Edward Island (PEI), airborne scanning laser altimetry (lidar) was employed to acquire high-resolution digital elevation models (DEMs) and other landscape information. The study area included both the Charlottetown urban area and an extensive portion of the rural North Shore of PEI. Problems with the lidar data included data gaps and incorrect classification of "ground" and "non-ground" laser hits along the waterfront. Accurate representation of wharves and other waterfront features in the DEM was achieved by combining "ground" and "non-ground" data. The importance of calibration and validation in lidar data acquisition and interpretation was demonstrated by three independent validation exercises that uncovered and adjusted for a vertical offset attributed to calibration problems. The ground DEM was adjusted to hydrographic chart datum and used to model flood extent at three storm-surge water levels, one observed in the record storm of 21 January 2000 and two higher levels representing flood scenarios under rising sea level. Flood modelling was executed in a geographic information system (GIS) on the gridded ground DEM. The resulting binary grids were vectorized along the flooding limit. Low-lying areas isolated from free exchange with the harbour were excluded from the flood area. Vectors depicting the storm-surge water lines for the three flood scenarios were implemented on the geographic information system (GIS) in the city planning department and overlain on property boundary and assessment layers. This study demonstrated that validated DEMs derived from airborne lidar data are efficient and adequate tools for mapping flood risk hazard zones in coastal communities.
Canadian Journal of Remote Sensing, 2006
Abstract. Coastal flooding from storm-surge events and sea-level rise is a major issue in Atlanti... more Abstract. 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 12 m higher ...
for salt marshes near the Cornwallis Estuary, Nova Scotia, and Fort Beausejour, New Brunswick, re... more for salt marshes near the Cornwallis Estuary, Nova Scotia, and Fort Beausejour, New Brunswick, respectively. The data were used to develop digital elevation models (DEM) of the two sites with a resolution of 1 metre and a vertical precision of +/-15 and +/-30 cm depending on the system used. Aerial photographs were also obtained, orthorectifi ed and mosaicked. These basins have a high tidal range which, at low tide, allowed a large portion of the inter-tidal zone to be surveyed, including tidal fl ats and salt marshes.
Journal of Marine Science and Engineering, 2015
Geomatica
This paper outlines a new software tool, Water Modeler, which is a component of a Coastal Zone De... more This paper outlines a new software tool, Water Modeler, which is a component of a Coastal Zone Decision Support System. The Water Modeler can analyze a time series of water-level records (tide gauge observations) to determine the risk associated with a high water level from a storm surge event or long-term sea-level rise. The new tool has been applied in two case studies in Nova Scotia, Canada, where coastal flood-risk maps have been derived from high-resolution LiDAR digital elevation models. The first case study is for Annapolis Royal on the Bay of Fundy side of the province, while the second looks at the Kingsburg area of Lunenburg County on the Atlantic shore. The Saint John, New Brunswick, and Halifax tide gauge records were used for Annapolis Royal and Kingsburg, respectively, in the Water Modeler to examine the risks of coastal flooding. The Groundhog Day storm of 1976, which caused coastal flooding around the Bay of Fundy, was used as a benchmark for Annapolis Royal. At curr...
Wetlands Ecology and Management
Much of the coast in the Canadian Maritimes is susceptible to erosion and flooding from storm-sur... more Much of the coast in the Canadian Maritimes is susceptible to erosion and flooding from storm-surge events and long-term sea-level rise. In recent years significant damage has occurred during storms in both urban and rural areas of the region. LiDAR technology has been employed to develop high-resolution digital elevation models (DEMs) as a basis for production of flood-risk maps. These
Research Monographs in GIS, 2004
Remote Sensing and Digital Image Processing, 2006
Using a LIDAR-Derived DEM FIGURE 7 Close-up of the three flood extents for the waterfront area of... more Using a LIDAR-Derived DEM FIGURE 7 Close-up of the three flood extents for the waterfront area of Charlottetown. The image is a color shaded relief of the DSM.
Canadian vessels equipped with multibeam bathymetry systems are in high demand by the Canadian Hy... more Canadian vessels equipped with multibeam bathymetry systems are in high demand by the Canadian Hydrographic Service (CHS) and by researchers from the Geological Survey of Canada (GSC). For several years, survey time for geological mapping was allocated in relatively small blocks of 10-20 days to provide as many applicants as possible the opportunity to collect multibeam bathymetry data. The resulting
Water, 2014
ABSTRACT The contamination of shellfish harvesting areas by fecal bacteria in the Annapolis Basin... more ABSTRACT The contamination of shellfish harvesting areas by fecal bacteria in the Annapolis Basin of Nova Scotia, Canada, is a recurring problem which has consequences for industry, government, and local communities. This study contributes to the development of an integrated water quality forecasting system to improve the efficiency and effectiveness of industry management. The proposed integrated forecasting framework is composed of a database containing contamination sources, hydrodynamics of the Annapolis Basin, Escherichia coli (E. coli) loadings and watershed hydrology scenarios, coupled with environmental conditions of the region (e. g., temperature, precipitation, evaporation, and ultraviolet light). For integration into this framework, this study presents a viable methodology for assessing the contribution of fecal bacteria originating from a watershed. The proposed methodology investigated the application of high resolution remote sensing, coupled with the commercially available product, MIKE 11, to monitor watershed land use and its impact on water quality. Remote sensing proved to be an extremely useful tool in the identification of sources of fecal bacteria contamination, as well as the detection of land use change over time. Validation of the MIKE 11 model produced very good agreement (R-2 = 0.88, E = 0.85) between predicted and observed river flows, while model calibration of E. coli concentrations showed fair agreement (R-2 = 0.51 and E = 0.38) between predicted and observed values. A proper evaluation of the MIKE 11 model was constrained due to limited water sampling. However, the model was very effective in predicting times of high contamination for use in the integrated forecasting framework, especially during substantial precipitation events.
Wetlands Ecology and Management, 2013
ABSTRACT Salt marshes exhibit striking vegetation zonation corresponding to spatially variable el... more ABSTRACT Salt marshes exhibit striking vegetation zonation corresponding to spatially variable elevation gradients which dictate their frequency of inundation by the tides. The salt marshes in the upper Bay of Fundy, a dynamic hypertidal system, are of considerable interest due to increasing recognition of salt marsh ecosystem values and the extent of prior conversion of salt marshes to agricultural lands, much of which are no longer in use. To determine the suitability of two potential restoration sites at Beausejour Marsh in New Brunswick, Canada, geomatics technologies and techniques were used to assess vegetation and elevation patterns in an adjacent reference salt marsh and the proposed restoration sites. Light detection and ranging digital elevation models (DEMs) were created for the reference marsh and the restoration sites in both the spring (leaf-off) and late summer (leaf-on, maximum biomass) periods. Aerial photographs and Quickbird multispectral imagery were used to visually interpret vegetation zones on the reference marsh and were field validated using vegetation characteristics from quadrats referenced with differential GPS. Elevation limits of the salt marsh vegetation zones were extracted from the DEM of the reference marsh and applied to the DEM of the restoration sites to determine the percentage area of each site that would be immediately suitable for new salt marsh growth. Of the two restoration sites assessed, one had experienced significant subsidence since dyking; only about 40 % of the site area was determined to be of sufficient elevation for immediate vegetation colonization. The second site, while more than 88 % suitable, would require the installation of a large dyke on the landward side of the restoration site to prevent flooding of adjacent lands. This study provides essential high resolution elevation and vegetation zonation data for use in restoration site assessments, and highlights the usefulness of applied geomatics in the salt marsh restoration planning process.
Water, 2014
Bridgewater, Nova Scotia, is located 20 km inland from the mouth of the LaHave River estuary on t... more Bridgewater, Nova Scotia, is located 20 km inland from the mouth of the LaHave River estuary on the Atlantic Coast of Canada. Bridgewater is at risk of flooding due to the combined effects of river runoff and a storm surge on top of high tide. Projected increases in sea-level and possible increased river runoff with climate change increase the risk of future flooding. A set of river and ocean water level simulations were carried out to determine the risk of flooding to Bridgewater today and in the future under climate change. The hydrodynamic simulation developed incorporates return periods of a time series of river discharge measurements for the LaHave watershed, ocean water dynamics at the mouth of the river under normal tidal conditions and with two levels of storm surge, near shore and river bathymetry, as well as high precision topographic lidar derived ground elevations and survey grade GPS. The study was supported by data from two tide gauge sensors, and qualitative evidence provided by the community such as historical flood levels and photographs. Results show that areas upstream of the town are vulnerable to large discharge events of the LaHave River. The downtown waterfront and infrastructure are not susceptible to fluvial flooding, but is vulnerable to sea-level rise and storm surge flooding.
Water, Air, & Soil Pollution, 2011
Sediment cores were analysed from four coastal wetland sites within the Minas Basin, Bay of Fundy... more Sediment cores were analysed from four coastal wetland sites within the Minas Basin, Bay of Fundy to compare mercury speciation and sediment characteristics. The coastal wetland sediments were low in total mercury (mean=17.4± 9.9 ng g −1 ); however, MeHg concentration was 92 times higher (mean of 249 pg g −1 ) than intertidal mudflat sediment (mean of 2.7 pg g −1 ). Total mercury concentrations in intertidal mudflat cores were also low (0.5-23.7 ng g −1 ) and correlated (Pearson correlation=0.98; p<0.01) with % organic
Journal of Coastal Research, 2011
CROWELL, N.; WEBSTER, T., and O'Driscoll, N.J., 2011. GIS modelling of intertidal wetland exposur... more CROWELL, N.; WEBSTER, T., and O'Driscoll, N.J., 2011. GIS modelling of intertidal wetland exposure characteristics.
Geocarto International, 2001
... Several basins developed in the Late Devonian - Early Carboniferous— including the Kennetcook... more ... Several basins developed in the Late Devonian - Early Carboniferous— including the Kennetcook, Shubenacadie (Giles and Boehner 1982) and St. Mary's Basins (Webster, 1996). ... 5). The structural deformation is localized within the basins - for example the Walton area (Fig. ...
Estuaries and Coasts, 2012
Analysis of dissolved organic matter (DOM) concentration and composition is essential to quantify... more Analysis of dissolved organic matter (DOM) concentration and composition is essential to quantifying biological and chemical oxygen demand and atmosphereocean heat flux exchange in natural waters. However, manual water sampling is costly and time consuming over large areas. The purpose of this research was to analyze the applicability of airborne laser-induced fluorescence light detection and ranging (LiDAR) for the detection of DOM in estuarine ecosystems impacted by agriculture. A fluorescence LiDAR system (Airborne Marine) (FLS-AM) was used to assess the DOM concentration of the Annapolis River and Basin, Nova Scotia, Canada, as well as three rivers and their estuaries in Prince Edward Island, Canada. Two FLS-AM flight missions were conducted in the summers of 2008 and 2009 and the resulting datasets were compared with spectral fluorescence signature (SFS DOM) and dissolved organic carbon (DOC) analysis of in situ water samples. Significant positive correlations were found at five of seven sites between the FLS-AM DOM and SFS DOM relationship which indicates that the FLS-AM sensor is a good surrogate for traditional sample collection of DOM data in estuaries in this region. Positive correlations were also found at all sites between FLS-AM DOM values and DOC. FLS-AM DOM patterns show that DOM values are significantly higher in rivers and estuaries that drain watersheds which are heavily impacted by agricultural practices. The results of this study show that the FLS-AM can be used efficiently as a general indicator for how estuaries are affected by runoff from agricultural watersheds in real time and thus reduce the requirement for traditional water sample collection and laboratory analysis methods.
Computers & Geosciences, 2006
High-resolution elevation surveys utilizing light detection and ranging (LIDAR) are becoming avai... more High-resolution elevation surveys utilizing light detection and ranging (LIDAR) are becoming available to the geoscience community to derive high-resolution DEMs that are used in a variety of application areas. However, prior to the application of these data to geomorphic interpretation, extensive validation procedures should be employed. The vertical accuracy specification for the survey called for heights to be within an average of 15 cm of measured GPS heights and 95% of the data to be within 30 cm. Two different LIDAR systems and collection methods were employed to collect data for the study area located in the Mesozoic Fundy Basin in eastern Canada. High-precision GPS surveys were conducted to measure the ground elevations in open areas and a traditional topographic survey was carried out in order to assess the accuracy of the laser data under the forest canopy. The LIDAR and validation data were integrated into a GIS where an automated procedure was developed that allows the user to specify a search radius out from the validation points in order to compare proximal LIDAR points. This procedure facilitates examining the LIDAR points and the validation data to determine if there are any systematic biases between flight lines in the LIDAR data. The results of the validation analysis of the two LIDAR methods and a description of the automated procedure are presented in this paper. r
Canadian Journal of Remote Sensing, 2004
As part of a recent project to determine coastal impacts of climate change and sea-level rise on ... more As part of a recent project to determine coastal impacts of climate change and sea-level rise on Prince Edward Island (PEI), airborne scanning laser altimetry (lidar) was employed to acquire high-resolution digital elevation models (DEMs) and other landscape information. The study area included both the Charlottetown urban area and an extensive portion of the rural North Shore of PEI. Problems with the lidar data included data gaps and incorrect classification of "ground" and "non-ground" laser hits along the waterfront. Accurate representation of wharves and other waterfront features in the DEM was achieved by combining "ground" and "non-ground" data. The importance of calibration and validation in lidar data acquisition and interpretation was demonstrated by three independent validation exercises that uncovered and adjusted for a vertical offset attributed to calibration problems. The ground DEM was adjusted to hydrographic chart datum and used to model flood extent at three storm-surge water levels, one observed in the record storm of 21 January 2000 and two higher levels representing flood scenarios under rising sea level. Flood modelling was executed in a geographic information system (GIS) on the gridded ground DEM. The resulting binary grids were vectorized along the flooding limit. Low-lying areas isolated from free exchange with the harbour were excluded from the flood area. Vectors depicting the storm-surge water lines for the three flood scenarios were implemented on the geographic information system (GIS) in the city planning department and overlain on property boundary and assessment layers. This study demonstrated that validated DEMs derived from airborne lidar data are efficient and adequate tools for mapping flood risk hazard zones in coastal communities.
Canadian Journal of Remote Sensing, 2006
Abstract. Coastal flooding from storm-surge events and sea-level rise is a major issue in Atlanti... more Abstract. 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 12 m higher ...