Map and discussion of the physical vulnerability of Hampton Roads to storm-surge flooding
The low-lying eastern portion of the study area is most at risk to storm surges from hurricanes of all categories. In particular, two major regions appear to be especially susceptible to storm-surge flooding. Much of the southern Hampton Roads is less than five meters above sea level. Locations near the coast along the Elizabeth and Nansemond Rivers are at risk of flooding from storm surges associated with even weak or moderate hurricanes. Because of this region's shallow slope, storm-surge waters from stronger hurricanes can affect locations much farther inland, including the Dismal Swamp region. For example, in the city of Chesapeake, about 50.15 km2 (5.5% of the city's total land area) are at risk of storm-surge flooding from Category 1 hurricanes. For Category 5 hurricanes, however, the storm-surge flood-risk zone is much larger, occupying 707.66 km2 (about 77.6% of the city).
The second distinct region at risk of storm-surge flooding is the eastern edge of the Peninsula, in a bowl-shaped depression known as the Chesapeake Bay Impact Crater. The crater was created about 35 million years ago by a comet or meteorite, and it occupies most of the cities of Poquoson and Hampton as well as the eastern portions of Gloucester and York counties. These areas are at risk of storm-surge flooding from even Category 1 hurricanes. However, because the region slopes steeply inland away from the edge of the depression, increases in hurricane intensity do not dramatically increase the size of the flood-risk zone. For example, the Category 1 storm-surge flood-risk zone occupies 90.82 km2 in Gloucester county, whereas the Category 5 risk zone occupies 173.12 km2 – an increase of only 82.3 km2.
Additionally, throughout the region, most locations immediately along the coasts are at risk of storm-surge flooding. Also, in Southampton county and the city of Franklin, wetlands along the Blackwater and Nottoway rivers are vulnerable.