It is not just the base at risk. Norfolk is situated in the largest and most vulnerable tidewater region in the U.S. It is also the region of the east coast that is expected to have the highest sea level rise as a result of being near the Gulf Stream which piles water upon the shore line. The Hampton Roads Metropolitan Statistical Area of which Norfolk is a part (officially known as the Virginia Beach-Norfolk-Newport News, VA-NC MSA) is the 37th largest in the United States, with an estimated population of 1,716,624 in 2014. All of this area is threatened by sea level rise. The city has a total area of 96 square miles (250 km2), of which 54 square miles (140 km2) is land and 42 square miles (110 km2) (43.9%) is water.
Norfolk is particularly vulnerable to rising sea levels. Some areas already flood regularly at high tide, and the city commissioned a study in 2012 to investigate how to address the issue in the future. It reported the cost of dealing with a sea-level rise of one foot would be around $1,000,000,000. Since then, scientists at the Virginia Institute of Marine Science in 2013 have estimated that if current trends hold, the sea in Norfolk will rise by 5 and 1/2 feet or more by the end of this century.
https://en.wikipedia.org/wiki/Norfolk,_VirginiaTides run between 3 and 4 feet in Norfolk and with a 5 feet rise in sea level, sea levels would be 8 feet higher at high tide by the end of the century.
The 1st image is of coastal tidewater regions.
The 2nd image is a tide forecast.
The 3rd image is the 8 foot flood map.
I would have to imagine that other cities in the region have similar issues they are facing.
That last image would suggest the city will be unlivable by the end of the century.