The High Water Mark (HWM) Initiative is a component of the National Flood Insurance Program (NFIP) aimed to increase local communities’ awareness of flood risk and encourage risk mitigation actions. The HWM Initiative uses signs on public and private property to show the high water mark from past flooding events, like Hurricane Irene in 2011 and Superstorm Sandy in 2012. The Monmouth County, NJ Division of Planning began working with the County Community Rating System (CRS) Assistance Program to compile data on the location of high water marks throughout the county resulting from Hurricane Irene in 2011 and Superstorm Sandy in 2012. The High Water Mark Story Map is accessible online where one can find the location of the signs throughout their community, as well as learn about past flooding events. Through this technology, the County and its Municipal partners create virtual tours of our past flooding events bringing awareness and education to all ages.The intention of this Story Map is to support resiliency and risk mitigation throughout Monmouth County municipalities. These efforts are from a joint partnership between Monmouth County Division of Planning, Monmouth County Office of Emergency Management, the Federal Emergency Management Agency’s National Flood Insurance Program, and Monmouth University’s Urban Coast Institute (UCI). The UCI works with Monmouth County and FEMA to provide free land surveying for County municipalities interested in participating in the Monmouth County HWM Initiative.Accessibility updated May 2023.

Future floodplain data prepared by Manhard in 2010. HEC-RAS files can be requested via an Open Records Request.FEMA Flood Hazard areas are available on the FEMA website.

Hurricane Sandy directly hit the Atlantic shoreline of New Jersey during several astronomical high tide cycles in late October, 2012. The eastern seaboard areas are subject to sea level rise and increased severity and frequency of storm events, prompting habitat and land use planning changes. Wetland Aquatic Research Center (WARC) has conducted detailed mapping of marine and estuarine wetlands and deepwater habitats, including beaches and tide flats, and upland land use/land cover, using specially-acquired aerial imagery flown at 1-meter resolution.These efforts will assist the U.S. Fish and Wildlife Service (USFWS) continuing endeavors to map the barrier islands adhering to Coastal Barrier Resources Act (CBRA) guidelines. Mapped areas consist of selected federal lands including, National Park Service areas, USFWS National Wildlife Refuges, and selected CBRA Units, including barrier islands and marshes in New York and New Jersey. These vital wetland areas are important for migratory waterfowl and neotropical bird habitats, wildlife food chain support and nurseries for shellfish and finfish populations. Coastal wetlands also play an important function as storm surge buffers. This project includes mapping of dominant estuarine wetland plant species useful for wetland functional analysis and wildlife evaluation and management concerns. It also aims to integrate with and offer updated databases pertinent to: USFWS NWR and NWI programs, NOAA tide flats and beaches data, FEMA flood zone data, Natural Heritage Endangered and Threated Species, watershed management, and state and local land use planning.

This dataset is available on Brisbane City Council’s open data website – data.brisbane.qld.gov.au. The site provides additional features for viewing and interacting with the data and for downloading the data in various formats.

Brisbane City Council Sandy Creek Flood Study. This dataset contains reports, data and metadata used in the flood study for the existing and ultimate floodplain condition scenarios.

Council is committed to ensuring we have the latest flood modelling data to help manage flood risk in Brisbane. Flood studies provide Council with technical data to inform policy and for managing flooding within the Brisbane River and local creek catchments.

For specifics details on how the study was conducted or areas it covers, and before using the data please read the following flood study reports:

• Sandy Creek Flood Study 2023 - Volume 1 of 2
• Sandy Creek Flood Study 2023 - Volume 2 of 2

The data on the table tab is the metadata relating to the data used for flood modelling in the Brisbane City Council Sandy Creek flood study. The metadata covers all resources in this dataset as well as the flood study reports provided as links in the dataset description.

More information on Flood studies and how this information is used can be found on the Brisbane City Council Website.

Note: Brisbane City Council’s information products — Flood Awareness Maps (FAM), FloodWise Property Reports (FWPR) and City Plan Flood Overlay Code — may not have the latest report data incorporated.
The image below indicates the locality of the catchment area of the flood study and creek centreline of the model.

Hurricane Sandy directly hit the Atlantic shoreline of New Jersey during several astronomical high tide cycles in late October, 2012. The eastern seaboard areas are subject to sea level rise and increased severity and frequency of storm events, prompting habitat and land use planning changes. Wetland Aquatic Research Center (WARC) has conducted detailed mapping of marine and estuarine wetlands and deepwater habitats, including beaches and tide flats, and upland land use/land cover, using specially-acquired aerial imagery flown at 1-meter resolution.These efforts will assist the U.S. Fish and Wildlife Service (USFWS) continuing endeavors to map the barrier islands adhering to Coastal Barrier Resources Act (CBRA) guidelines. Mapped areas consist of selected federal lands including, National Park Service areas, USFWS National Wildlife Refuges, and selected CBRA Units, including barrier islands and marshes in New York and New Jersey. These vital wetland areas are important for migratory waterfowl and neotropical bird habitats, wildlife food chain support and nurseries for shellfish and finfish populations. Coastal wetlands also play an important function as storm surge buffers. This project includes mapping of dominant estuarine wetland plant species useful for wetland functional analysis and wildlife evaluation and management concerns. It also aims to integrate with and offer updated databases pertinent to: USFWS NWR and NWI programs, NOAA tide flats and beaches data, FEMA flood zone data, Natural Heritage Endangered and Threated Species, watershed management, and state and local land use planning.

Hurricane Sandy directly hit the Atlantic shoreline of New Jersey during several astronomical high tide cycles in late October, 2012. The eastern seaboard areas are subject to sea level rise and increased severity and frequency of storm events, prompting habitat and land use planning changes. Wetland Aquatic Research Center (WARC) has conducted detailed mapping of marine and estuarine wetlands and deepwater habitats, including beaches and tide flats, and upland land use/land cover, using specially-acquired aerial imagery flown at 1-meter resolution.These efforts will assist the U.S. Fish and Wildlife Service (USFWS) continuing endeavors to map the barrier islands adhering to Coastal Barrier Resources Act (CBRA) guidelines. Mapped areas consist of selected federal lands including, National Park Service areas, USFWS National Wildlife Refuges, and selected CBRA Units, including barrier islands and marshes in New York and New Jersey. These vital wetland areas are important for migratory waterfowl and neotropical bird habitats, wildlife food chain support and nurseries for shellfish and finfish populations. Coastal wetlands also play an important function as storm surge buffers. This project includes mapping of dominant estuarine wetland plant species useful for wetland functional analysis and wildlife evaluation and management concerns. It also aims to integrate with and offer updated databases pertinent to: USFWS NWR and NWI programs, NOAA tide flats and beaches data, FEMA flood zone data, Natural Heritage Endangered and Threated Species, watershed management, and state and local land use planning.

Roads and flood maps for two Iowa counties: Johnson and Benton

Hurricane Sandy directly hit the Atlantic shoreline of New Jersey during several astronomical high tide cycles in late October, 2012. The eastern seaboard areas are subject to sea level rise and increased severity and frequency of storm events, prompting habitat and land use planning changes. Wetland Aquatic Research Center (WARC) has conducted detailed mapping of marine and estuarine wetlands and deepwater habitats, including beaches and tide flats, and upland land use/land cover, using specially-acquired aerial imagery flown at 1-meter resolution.These efforts will assist the U.S. Fish and Wildlife Service (USFWS) continuing endeavors to map the barrier islands adhering to Coastal Barrier Resources Act (CBRA) guidelines. Mapped areas consist of selected federal lands including, National Park Service areas, USFWS National Wildlife Refuges, and selected CBRA Units, including barrier islands and marshes in New York and New Jersey. These vital wetland areas are important for migratory waterfowl and neotropical bird habitats, wildlife food chain support and nurseries for shellfish and finfish populations. Coastal wetlands also play an important function as storm surge buffers. This project includes mapping of dominant estuarine wetland plant species useful for wetland functional analysis and wildlife evaluation and management concerns. It also aims to integrate with and offer updated databases pertinent to: USFWS NWR and NWI programs, NOAA tide flats and beaches data, FEMA flood zone data, Natural Heritage Endangered and Threated Species, watershed management, and state and local land use planning.

Hurricane Sandy, which made landfall on October 29, 2012, near Brigantine, New Jersey, had a significant impact on coastal New Jersey, including the large areas of emergent wetlands at Edwin B. Forsythe National Wildlife Refuge (NWR) and the Barnegat Bay region. In response to Hurricane Sandy, U.S. Geological Survey (USGS) has undertaken several projects to assess the impacts of the storm and provide data and scientific analysis to support recovery and restoration efforts. As part of these efforts, the USGS Coastal and Marine Geology Program (CMGP) sponsored Coastal National Elevation Database (CoNED) Applications Project in collaboration with the USGS National Geospatial Program (NGP), and National Oceanic and Atmospheric Administration (NOAA) developed a three-dimensional (3D) 1-meter topobathymetric elevation models (TBDEMs) for the New Jersey/Delaware sub-region including the Delaware Estuary and adjacent coastline. The integrated elevation data are extending the USGS 3D Elevation Program (3DEP) Elevation Dataset within the Hurricane Sandy impact zone to enable the widespread creation of flood, hurricane, and sea-level rise inundation hazard maps. More information on the USGS CoNED project is available at http://topotools.cr.usgs.gov/coned/index.php. The CoNED Applications Project team is also developing new applications for pre- and post-Hurricane Sandy regional lidar datasets for mapping the spatial extent of coastal wetlands. These new methods have been developed to derive detailed land/water polygons for an area in coastal New Jersey, which is dominated by a complex configuration of emergent wetlands and open water. Using pre- and post-Hurricane Sandy lidar data, repeatable geospatial methods were used to map the land/water spatial configuration at a regional scale to complement wetland mapping that uses traditional methods such as photointerpretation and image classification.

The study area is approximately 625 km2 , which includes Kaduna town at the centre with large settlements like Tudun Nupawa, Kurmin Mashi, Mondo and Rigasa to the west; Kabala and Barnawa to the south; Malali and Unguwan Rimi to the east; and Unguwar Kanawa, Badarawa and Rigachukun to the east. The major river channel is the River Kaduna which cuts the area from west to east. Other rivers are River Gora to the south and River Kura to the north. There are many streams in the area. The topography is virtually flat lying and the relief of the area ranges from 590m and 653m.\r The entire project area is underlain by Precambrian migmatite-gneiss complex which constitutes a greater part of the project area; the Pan Africa granitoids which constitute the second largest suit of rocks in the area; and lastly Metasediments/metavolcanics; mostly schists. The soils derived from these rocks are gravelly clays, sandy clays, clays and clayey gravels. Gravelly clays cover about 33% (208km2 ) of the area, sandy clays cover about 6% (37km 2 ) of the area, clays cover about 41% ( 256km2 ) of the area, clayey gravels cover about 6% (37km2 ) and alluvial silty clays cover about 12% (80 km2 ) of the area. \r Eight geotechnical factors were evaluated for the project area: soil bearing capacity, soil compressibility, soil expansivity, soil permeability, slope instability, soil erodibility, flooding and soil acidity.\r Reddish-brown to red, stiff to hard, residual lateritic gravelly clays cover about 33% (208km2) of the study area. They have high bearing capacities at shallow depth, low compressibility, and they are virtually free from highly expansive clays. They are therefore good founding materials at shallow depth. They have medium permeability and they are of low to medium plasticity.\r Reddish-brown to red, stiff to hard residual lateritic sandy clays cover about 6% (37km2) of the study area. They have high bearing capacities at shallow depth, low compressibility and they are virtually free from highly expansive clays. They are therefore good founding materials at shallow depth. They have medium permeability and they are of low to medium plasticity.\r Reddish-brown to red, stiff to hard residual lateritic clays cover about 41% (256km2) of the study area. They have high bearing capacities at shallow depth, low compressibility and they are free from highly expansive clays. They are therefore good founding materials at shallow depth. They have low permeability and they are of low to medium plasticity.\r Reddish brown to red, medium dense to dense residual lateritic clayey gravels cover about 6% (37 km2) of the area. They have high bearing capacities at shallow depth, low compressibility and they are free from highly expansive clays. They are therefore good founding materials at shallow depth. They have high permeability and they are of low to medium plasticity.\r Grey to brown, soft to firm, alluvial silty clays cover about 12% (80km2) of the area. They have low bearing capacities at shallow depth. They are therefore not good founding materials at shallow depth, especially for heavy loaded structures. They have low compressibility and they are free from highly expansive clays. They also have low permeability and they are of low to medium plasticity.\r The area is flat lying; there are no slopes or erosion sites which will pose a problem in the study area.\r The streams constitute the main flood paths during the rainy season when they overflow their channels and the flood zones are the flood plains and the fadama areas along Rivers Kaduna, Gora, Kura and their tributaries. Flooding is expected for about 10% (65 km2 ) of the study area.\r The entire soils are slightly acidic (pH = 5 or 6 ). The acidity is not strong enough to course any environmental, agricultural or engineering problem.\r A total of six geotechnical maps have been produced: (i) suitable and unsuitable sites for housing estate development map (ii) suitable areas for waste disposal map (iii) potential flood zone map (iv) Land form map (v) structural map and (vi) documentation map.\r The geotechnical map showing suitable and unsuitable sites for housing estate development shows that 79% (495 Km2 ) of the area is suitable for light loaded housing estate development (like simple houses with wall load of up to 100 KN /m and 1 or 2 storey houses with column load of up to 250 KN) because the soils have high bearing capacities at shallow depth, low compressibility and they are virtually free from highly expansive clays. The areas are not susceptible to erosion or flooding. The map also shows that about 21% (130 Km2)of the area is not suitable for housing estate development because the soils have low bearing capacities at shallow depth and the areas are susceptible to flooding. \r The geotechnical map showing suitable areas for waste disposal shows that about 5% (32km2 ) of the area is suitable for waste disposal because the soils have low permeability, the areas are flat lying or slightly elevated and far away from settlements. Water tables are also very low.\r The geotechnical map showing potential flood zones area shows that about 10% (65km2) of the study area is susceptible to flooding because the areas are the flood plains and fadama areas of Rivers Kaduna, Gora, Kura and their tributaries. \r The land form map shows elevated flat lying lands, low lying flood plains, fadama areas and water courses.\r The structural map shows fractures, joints and faults in the study area. \r The documentation map shows the positions of 93 trial pits (TP) dug and 16 drill holes ( BH) drilled on a geological map.
\r

This dataset is available on Brisbane City Council’s open data website – data.brisbane.qld.gov.au. The site provides additional features for viewing and interacting with the data and for downloading the data in various formats.

Brisbane City Council Citywide Creek and Overland Flow Path Mapping Flood Study Wolston Sandy Sub-Model. This dataset contains reports, data and metadata used in the flood study, and results data for the existing floodplain condition scenarios.

Council is committed to ensuring we have the latest flood modelling data to help manage flood risk in Brisbane. Flood studies provide Council with technical data to inform policy and for managing flooding within the Brisbane River and local creek and overland flow catchments.

The Citywide Creek and Overland Flow Path Mapping Flood Study comprises a series of 27 individual sub-models which cover the entire Brisbane City Council area. Results data for flood height, depth and hazard (depth x velocity) are available for each individual sub-model for the 2, 5, 10, 20, 50, 100, 500 and 2000 year Average Recurrence Interval (ARI) storm events.

For specific details on how the study was conducted, the areas it covers, and before using the data please read the flood study report. The flood study report, metadata used in the flood study and a detailed map that shows the 27 individual sub-models has also been made available in open data and is called Flood Study — Citywide Overland Flow — reference.

The data on the table tab is the metadata relating to the data used for flood modelling in the Brisbane City Council Citywide Creek and Overland Flow Path Mapping Flood Study.

More information on flood studies and how this information is used can be found on the Brisbane City Council Website.
The image below shows the 27 individual sub-models of the flood study and can be used to identify the sub-model for your location of interest.

Hurricane Sandy directly hit the Atlantic shoreline of New Jersey during several astronomical high tide cycles in late October, 2012. The eastern seaboard areas are subject to sea level rise and increased severity and frequency of storm events, prompting habitat and land use planning changes. Wetland Aquatic Research Center (WARC) has conducted detailed mapping of marine and estuarine wetlands and deepwater habitats, including beaches and tide flats, and upland land use/land cover, using specially-acquired aerial imagery flown at 1-meter resolution.These efforts will assist the U.S. Fish and Wildlife Service (USFWS) continuing endeavors to map the barrier islands adhering to Coastal Barrier Resources Act (CBRA) guidelines. Mapped areas consist of selected federal lands including, National Park Service areas, USFWS National Wildlife Refuges, and selected CBRA Units, including barrier islands and marshes in New York and New Jersey. These vital wetland areas are important for migratory waterfowl and neotropical bird habitats, wildlife food chain support and nurseries for shellfish and finfish populations. Coastal wetlands also play an important function as storm surge buffers. This project includes mapping of dominant estuarine wetland plant species useful for wetland functional analysis and wildlife evaluation and management concerns. It also aims to integrate with and offer updated databases pertinent to: USFWS NWR and NWI programs, NOAA tide flats and beaches data, FEMA flood zone data, Natural Heritage Endangered and Threated Species, watershed management, and state and local land use planning.

description: These data were created as part of the National Oceanic and Atmospheric Administration Office for Coastal Management's efforts to create an online mapping viewer called the Sea Level Rise and Coastal Flooding Impacts Viewer. It depicts potential sea level rise and its associated impacts on the nation's coastal areas. The purpose of the mapping viewer is to provide coastal managers and scientists with a preliminary look at sea level rise and coastal flooding impacts. The viewer is a screening-level tool that uses nationally consistent data sets and analyses. Data and maps provided can be used at several scales to help gauge trends and prioritize actions for different scenarios. The Sea Level Rise and Coastal Flooding Impacts Viewer may be accessed at: https://coast.noaa.gov/slr. This metadata record describes the North Carolina, Southern 1 digital elevation model (DEM), which is a part of a series of DEMs produced for the National Oceanic and Atmospheric Administration Office for Coastal Management's Sea Level Rise and Coastal Flooding Impacts Viewer described above. This DEM includes the best available lidar known to exist at the time of DEM creation that met project specifications. This DEM includes data for Bladen, Brunswick, Columbus, New Hanover, and Pender Counties. The DEM was produced from the following lidar data sets: 1. 2014 NGS Coastal Mapping Program Topobathy Lidar: Post-Sandy Atlantic Seaboard 2. 2014 NC Statewide Lidar - Phase 2 The DEM is referenced vertically to the North American Vertical Datum of 1988 (NAVD88) with vertical units of meters and horizontally to the North American Datum of 1983 (NAD83). The resolution of the DEM is approximately 3 meters.; abstract: These data were created as part of the National Oceanic and Atmospheric Administration Office for Coastal Management's efforts to create an online mapping viewer called the Sea Level Rise and Coastal Flooding Impacts Viewer. It depicts potential sea level rise and its associated impacts on the nation's coastal areas. The purpose of the mapping viewer is to provide coastal managers and scientists with a preliminary look at sea level rise and coastal flooding impacts. The viewer is a screening-level tool that uses nationally consistent data sets and analyses. Data and maps provided can be used at several scales to help gauge trends and prioritize actions for different scenarios. The Sea Level Rise and Coastal Flooding Impacts Viewer may be accessed at: https://coast.noaa.gov/slr. This metadata record describes the North Carolina, Southern 1 digital elevation model (DEM), which is a part of a series of DEMs produced for the National Oceanic and Atmospheric Administration Office for Coastal Management's Sea Level Rise and Coastal Flooding Impacts Viewer described above. This DEM includes the best available lidar known to exist at the time of DEM creation that met project specifications. This DEM includes data for Bladen, Brunswick, Columbus, New Hanover, and Pender Counties. The DEM was produced from the following lidar data sets: 1. 2014 NGS Coastal Mapping Program Topobathy Lidar: Post-Sandy Atlantic Seaboard 2. 2014 NC Statewide Lidar - Phase 2 The DEM is referenced vertically to the North American Vertical Datum of 1988 (NAVD88) with vertical units of meters and horizontally to the North American Datum of 1983 (NAD83). The resolution of the DEM is approximately 3 meters.

These data were created as part of the National Oceanic and Atmospheric Administration Office for Coastal Management's efforts to create an online mapping viewer called the Sea Level Rise and Coastal Flooding Impacts Viewer. It depicts potential sea level rise and its associated impacts on the nation's coastal areas. The purpose of the mapping viewer is to provide coastal managers and scientists with a preliminary look at sea level rise and coastal flooding impacts. The viewer is a screening-level tool that uses nationally consistent data sets and analyses. Data and maps provided can be used at several scales to help gauge trends and prioritize actions for different scenarios. The Sea Level Rise and Coastal Flooding Impacts Viewer may be accessed at: https://coast.noaa.gov/slr. This metadata record describes the New York, Metro digital elevation model (DEM), which is a part of a series of DEMs produced for the National Oceanic and Atmospheric Administration Office for Coastal Management's Sea Level Rise and Coastal Flooding Impacts Viewer described above. This DEM includes the best available lidar known to exist at the time of DEM creation that met project specifications. This DEM includes data for Bronx, Kings, Nassau, New York, Queens, Richmond, Rockland, and Westchester Counties. The DEM was produced from the following lidar data sets: 1. 2014 NGS Coastal Mapping Program Topobathy Lidar: Post-Sandy Atlantic Seaboard 2. 2014 USGS New York CMGP Sandy Lidar 3. 2014 Long Island, NY - Sandy Lidar 4. 2011-2012 New York Coastal Lidar 5. 2009 New York City Water Lidar - East of Hudson The DEM is referenced vertically to the North American Vertical Datum of 1988 (NAVD88) with vertical units of meters and horizontally to the North American Datum of 1983 (NAD83). The resolution of the DEM is approximately 3 meters.

Brisbane City Council Sandy Creek Flood Study. This dataset contains reports, data and metadata used in the flood study for the existing and ultimate floodplain condition scenarios.Council is committed to ensuring we have the latest flood modelling data to help manage flood risk in Brisbane. Flood studies provide Council with technical data to inform policy and for managing flooding within the Brisbane River and local creek catchments.For specifics details on how the study was conducted or areas it covers, and before using the data please read the following flood study reports: • Sandy Creek Flood Study 2023 - Volume 1 of 2 • Sandy Creek Flood Study 2023 - Volume 2 of 2The data on the table tab is the metadata relating to the data used for flood modelling in the Brisbane City Council Sandy Creek flood study. The metadata covers all resources in this dataset as well as the flood study reports provided as links in the dataset description.More information on Flood studies and how this information is used can be found on the Brisbane City Council Website.Note: Brisbane City Council’s information products — Flood Awareness Maps (FAM), FloodWise Property Reports (FWPR) and City Plan Flood Overlay Code — may not have the latest report data incorporated.The image below indicates the locality of the catchment area of the flood study and creek centreline of the model.

Brisbane City Council Albany Creek Flood Study. This dataset contains reports, data and metadata used in the flood study for the existing and ultimate floodplain condition scenarios.Council is committed to ensuring we have the latest flood modelling data to help manage flood risk in Brisbane. Flood studies provide Council with technical data to inform policy and for managing flooding within the Brisbane River and local creek catchments.For specifics details on how the study was conducted or areas it covers, and before using the data please read the following flood study reports: • Albany Creek Flood Study - Volume 1 of 2 • Albany Creek Flood Study - Volume 2 of 2The data on the table tab is the metadata relating to the data used for flood modelling in the Brisbane City Council Albany Creek flood study.

The metadata covers all resources in this dataset as well as the flood study reports provided as links in the dataset description.More information on Flood studies and how this information is used can be found on the Brisbane City Council Website.The image below indicates the locality of the catchment area of the flood study and creek centreline of the model.

Flood Zones for Hobart, Newtown and Sandy Bay rivulets. 100yr AEP cc for Hobart and Sandy Bay rivulets.

These data were created as part of the National Oceanic and Atmospheric Administration Office for Coastal Management's efforts to create an online mapping viewer called the Sea Level Rise and Coastal Flooding Impacts Viewer. It depicts potential sea level rise and its associated impacts on the nation's coastal areas. The purpose of the mapping viewer is to provide coastal managers and scientists with a preliminary look at sea level rise and coastal flooding impacts. The viewer is a screening-level tool that uses nationally consistent data sets and analyses. Data and maps provided can be used at several scales to help gauge trends and prioritize actions for different scenarios. The Sea Level Rise and Coastal Flooding Impacts Viewer may be accessed at: https://coast.noaa.gov/slr. This metadata record describes the Virginia, Southern digital elevation model (DEM), which is a part of a series of DEMs produced for the National Oceanic and Atmospheric Administration Office for Coastal Management's Sea Level Rise and Coastal Flooding Impacts Viewer described above. This DEM includes the best available lidar known to exist at the time of DEM creation that met project specifications. This DEM includes data for Chesapeake, Chesterfield, Colonial Heights, Franklin City, Hopewell, Isle of Wight, Norfolk, Petersburg, Portsmouth, Prince George, Richmond City, Southampton, Suffolk, Surry, and Virginia Beach Counties. The DEM was produced from the following lidar data sets: 1. 2014 NGS Coastal Mapping Program Topobathy Lidar: Post-Sandy Atlantic Seaboard 2. 2013 USGS Norfolk, VA Lidar 3. 2014 Virginia Hurricane Sandy QL2 Lidar 4. 2011 FEMA Virginia Lidar 5. 2010 ARRA-VA 11County The DEM is referenced vertically to the North American Vertical Datum of 1988 (NAVD88) with vertical units of meters and horizontally to the North American Datum of 1983 (NAD83). The resolution of the DEM is approximately 3 meters.

Apalachicola Bay and St. George Sound contain the largest oyster fishery in Florida, and the growth and distribution of the numerous oyster reefs here are the combined product of modern estuarine conditions and the late Holocene evolution of the bay. A suite of geophysical data and cores were collected during a cooperative study by the U.S. Geological Survey, the National Oceanic and Atmospheric Administration Coastal Services Center, and the Apalachicola National Estuarine Research Reserve to refine the geology of the bay floor as well as the bay's Holocene stratigraphy. Sidescan-sonar imagery, bathymetry, high-resolution seismic profiles, and cores show that oyster reefs occupy the crests of sandy shoals that range from 1 to 7 kilometers in length, while most of the remainder of the bay floor is covered by mud. The sandy shoals are the surficial expression of broader sand deposits associated with deltas that advanced southward into the bay between 6,400 and 4,400 years before present. The seismic and core data indicate that the extent of oyster reefs was greatest between 2,400 and 1,200 years before present and has decreased since then due to the continued input of mud to the bay by the Apalachicola River. The association of oyster reefs with the middle to late Holocene sandy delta deposits indicates that the present distribution of oyster beds is controlled in part by the geologic evolution of the estuary. For more information on the surveys involved in this project, see http://woodshole.er.usgs.gov/operations/ia/public_ds_info.php?fa=2005-001-FA and http://woodshole.er.usgs.gov/operations/ia/public_ds_info.php?fa=2006-001-FA.