The Chesapeake Bay area, located on the East Coast of the United States, is one of the country’s regions that’s most vulnerable to climate change, according to the Chesapeake Bay Program, a regional partnership that has conducted wide-ranging bay restoration projects for more than 40 years.
According to the National Oceanic and Atmospheric Administration (NOAA), the bay will likely undergo sea level rise of 1.3–5.2 feet (0.4–1.6 meters) during the next century—more than the global average—due to climate change, groundwater removal, and land subsidence. This would intensify the already-intensifying impact of storm surges generated by hurricanes and other weather-related events. With more extreme weather due to climate change, NOAA expects increases in coastal flooding and shoreline erosion, as well as changes in local wildlife abundance and migration patterns.
Located on the Chesapeake Bay’s eastern shore and with an average elevation of only about three feet (0.9 meters) above sea level, the city of Crisfield, Maryland, has high flooding risk. In 2012, a storm surge from Hurricane Sandy flooded most of the city, highlighting issues that are being tracked by Chesapeake Bay Program partners such as the US Geological Survey and NOAA. Using ArcGIS Pro, ArcGIS Online, and 3D landscape visualization, Chesapeake Bay Program partners created a digital twin of Crisfield to help the flood mitigation team develop a flood adaptation assessment to enhance community resilience.
Digital Twin Shows Flooding Scenarios
The Chesapeake Bay Program team used 3D Basemaps to create the digital twin and employed ArcGIS Pro to generate the 3D terrain, buildings, and vegetation from lidar data and digital building footprints. Dr. André de Souza de Lima and his colleagues at George Mason University’s Flood Hazards Research Lab developed flood scenarios based on NOAA’s coastal high-tide flooding mapping methodology.
“Crisfield’s digital twin enables users to see the extent of flooding under different hazard and adaptation scenarios,” said John Wolf, a US Geological Survey geographer and the GIS team leader for the Chesapeake Bay Program. Wolf’s team oversees landscape monitoring and modeling while leading the development of related data communication and visualization products.
To help show potential flooding impacts to buildings and other important local assets in the digital twin, the team downloaded building footprints and lidar data from the MD iMAP Portal, Maryland’s enterprise GIS resource. The team also used property data from iMAP to add parcel-scale valuation data to the basemap.
“The building footprints were enhanced with additional attributes originating from parcel data through spatial joins,” Wolf said. “As a result, we were able to approximate the total assessed value of buildings that could be impacted under various flooding scenarios.”
Optimizing 3D Visualizations
The team published 3D visualizations to ArcGIS Online, with animated water and atmospheric effects added in Scene Viewer. Because the team members also wished to show historical context for the city, which was incorporated in 1872, they used maps from 1897 that had been created for the fire insurance industry to exhibit streets, buildings, and other details.
To help with community resilience planning, the City of Crisfield flood mitigation team and others can use several interactive 3D visualizations that Wolf’s team developed based on insight from scientists from The Nature Conservancy, the University of Maryland Environmental Finance Center, George Mason University, and the US Environmental Protection Agency. As examples, one visualization shows the extent of flooding and impacted buildings from a 1.5-foot (0.46-meter) water-level hazard while another illustrates the effects that would be expected if the city faced a storm comparable to Hurricane Isabel, which flooded large sections of Maryland’s eastern shore in 2003.
Using ArcGIS Pro and Site Scan for ArcGIS, the Chesapeake Bay Program team is also collaborating with the Chesapeake Conservancy to develop an integrated mesh dataset to further improve realism. “The current version of the Crisfield scenes uses 3D building and vegetation models that approximate the vertical landscape structure,” said Wolf. “But an imagery-based integrated mesh version will present a more authentic depiction of the city.”
While this digital twin approach to studying coastal flooding is relatively new, it could be applied to communities all around the bay and its tributaries—an area that represents 11,684 miles (18,804 kilometers) of shoreline and 4,480 square miles (7,210 square kilometers) of surface area. In fact, a similar project is underway in Norfolk, Virginia.
“I hope these examples will serve as prototypes for other communities along the Chesapeake Bay coastline at risk of sea level rise,” said Wolf.
