Rising seas lead to rising costs

A new study published in the journal, Science Advances, found that in 2017, businesses in the vicinity of the City Dock in historic downtown Annapolis, Md., lost between $86,000 and $172,000 in revenue due to nuisance flooding. The study’s authors used data from nearby parking lots to determine that nearly 3,000 fewer people visited these businesses throughout 2017 than they project would have visited that year without any nuisance flooding.

Nuisance, or sunny-day, flooding is relatively low-level flooding that occurs with high tides. As the sea level, and therefore the water level in the Bay, rises, this kind of flooding is becoming increasingly common. This is especially true of areas like Annapolis, where the sea level is rising quicker than the global average—as much as two to four times faster, according to the study.

Annapolis experienced 63 days of nuisance flooding in 2017, compared to an average of only 3.8 days per year in 1957-1963. A 2014 report from the Union of Concerned Scientists estimates that by 2030, Annapolis will see more than 180 tidal floods each year.

The study found that each nuisance flood event could cause a 37 to 89 percent drop in visitors to the businesses near City Dock, depending on the severity of the flood. In addition, they found that the drop in visitors continues even once water levels recede.

These impacts aren’t future projections—they’re hitting local communities right now. The study states that “the losses due to recurrent flooding are already affecting the profitability of these businesses, and the losses will worsen as sea level rises unless changes are made.”

Annapolis sea level has already risen approximately a foot since 1950. The study projects that if the water rises just another foot the number of visitors to City Dock will drop by 24 percent compared to a year without nuisance flooding—a much steeper loss than the 1.7 percent drop found in 2017.

Annapolis is not alone in experiencing these floods. The Union of Concerned Scientists estimate that by 2045, Washington, D.C., will experience close to 400 tidal floods each year—more than anywhere else on the East Coast. The same report also states that “five locations in the Chesapeake Bay area, including Baltimore and its flood-prone Inner Harbor, are projected to be underwater for more than 875 hours a year—10 percent of the time—by 2045.”

Learn more about the effects of climate change in the Chesapeake Bay area.