Scientists at the Virginia Institute of Marine Science have been gathering data on sea level rise from tide gauge stations around the United States, including one at the mouth of the James River in Norfolk.
For three years they've issued a so-called sea level rise report card. Recently released 2019 data confirms sea levels are rising faster than first thought.
Data for the report cards goes back more than 50 years and has been used to confirm sea-level is rising along U.S. mainland Coasts and Alaska.
Researcher Molly Mitchell says the more years of data they have the better they can see what's going on. "We know the sea-level has been rising but the rate of rise was so small that it was hard to recognize that it was increasing," Mitchell says. "As we've gotten more and more data we're getting to a point where that increase is becoming more noticeable in the tide records."
So back in the 1950s and 60s sea levels were rising less than one-eighth of an inch, hardly noticeable. But, that slow acceleration of sea level rise works a bit like compound interest, building up over the years.
If the trend continues, 30 years from now, Norfolk is looking at an increase in sea level of about a foot-and-a-half. That means more frequent flooding for areas that now flood a couple of times a month. "The other thing it means is that the storm surges that come in will be on top of that extra foot-and-a-half of sea level," according to Mitchell. "So, a storm surge that today is four feet, in 2050 is at a five-and a-half foot elevation."
That would put most of the city under water, according to the Army Corps of Engineers. Last year, the Corps proposed a $1.4 billion project to build storm-surge barriers, nearly eight miles of floodwall, a levee, tide gates, and pump and power stations. Virginia's Senators and Representatives just requested $5.4 million to complete the preliminary engineering and design.