Frequent high-tide flooding can affect coastal communities' economy: Study

People living in coastal areas are highly affected by economic losses caused by frequent flooding and the impact worsens when the sea level rises, making them more frequent, says a new study.

Researchers from Stanford University in the US analysed the economic impact of frequent high-tide flooding in Annapolis, a coastal city in the US, and found that it suffered a loss of 3,000 visits in 2017 due to high-tide flooding, which equates to a loss of somewhere between $86,000 and $172,000 in revenue.

"Small businesses in downtown Annapolis rely on visitors. By measuring the extent of the impact of flooding, we can understand the business case -- how rise in sea levels is already impacting businesses' experiences and profits," said Samanthe Belanger, co-author of the study.

High-tide flooding, sometimes called nuisance flooding or sunny-day flooding, happens when ocean waters rise above the levels that coastal infrastructure was designed for. In case of high-tide flooding, water sweeps in, filling streets and parking lots and preventing normal pedestrian and vehicle traffic.

The average number of high-tide flooding days across 27 locations in the US went up from 2.1 days per year in the late 1950s to 11.8 days per year during 2006-2010.

By 2035, about 170 coastal communities are projected to experience 26 high-tide flooding days a year.

"As global temperatures and sea levels rise, high-tide flooding is becoming more frequent. For coastal businesses, that means more days when customers might not be able to get to their stores. Even though most floods only last for a few hours, their impacts can add up," said Miyuki Hino, a graduate student at the varsity.

Annapolis, home to the US Naval Academy, tops the list of cities experiencing a rise in high-tide flooding. In the early 1960s, Annapolis had about four high-tide flooding days a year.

In 2017, the loss to City Dock businesses due to flooding was less than 2 per cent of annual visitors, but that could get a lot worse as sea levels continue to rise, the researchers warned. City Dock is the historic heart of Annapolis.

Furthermore, if the sea level increases by three more inches, visits to the City Dock would be reduced by about 4 per cent, projected the study, published in the journal Science Advances.

In addition, with 12 inches of sea level rise, visits would be reduced by about 24 per cent, a figure that could mean hundreds of thousands in lost revenue, as per the researchers.

The US Global Change Research Programme Climate Science special report has sea level rise projections relative to the year 2000 ranging between 0.5 and 1.2 feet by 2050.

--IANS

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