If you visit one of Hampton Roads’ many waterways, you’ve likely at some point encountered a sign warning that it’s unsafe to get in the water.
The Virginia Department of Health issues these swimming advisories to warn beachgoers of harmful bacteria that can cause skin rashes or gastrointestinal illness.
Swimming was temporarily prohibited at a central section of the Virginia Beach Oceanfront last week, for example.
Beach advisories and the problems that cause them are nothing new, but they could become more frequent because of environmental factors linked to climate change.
What’s happening in the water?
Between May and September, the state health department tests water weekly at 48 beaches in Virginia, including several sites at the Oceanfront, Norfolk’s Ocean View, Fort Monroe, Hampton’s Buckroe Beach, Yorktown and Newport News.
Officials set out with 100-milliliter bottles attached to poles that they extend about a half-meter into the water to collect a sample, said Margaret Smigo, VDH’s waterborne hazards manager.
They also take note of conditions on the beach, including the weather, what animals are present and how much trash is lying around – all factors that can influence water quality.
Back at a lab, officials then look for indicators of bacteria like E. coli that can make people sick: “basically poop, or fecal matter in the water,” Smigo said.
The samples have to incubate for 24 hours before results can be read, which means by the time the department issues an advisory, “we’re already 24 hours behind,” Smigo said.
That’s part of why the warnings come and go quickly. Most last only a day, Smigo said, after officials retest the site and determine the water’s safe again.
Wet weather is usually the dominant factor in causing an advisory.
When it rains, everything washes off city sidewalks, streets and parks into storm drains. That means pet waste, fertilizer and cigarette butts are fed into and pollute local waterways.
Smigo said VDH recommends people avoid swimming in local water bodies altogether for about three days after heavy rain, because the connection is so clear.
And heavy rains will happen more often.
Climate impacts
There are two main ways climate change impacts Virginia’s water systems, said Joe Wood, senior scientist with the Chesapeake Bay Foundation.
There’s more frequent and intense rainfall, driven by rising evaporation as the planet warms. Those rains exacerbate stormwater pollution that leads to bacteria or algae growth, Wood said.
“You have this increased vector for pollution to be delivered quickly, the increased number of events when you have rainfall, where lots of E. coli or lots of nutrients can be washed into a waterway quickly and promote one of these events.”
Smigo said VDH has occasionally seen heavier rains have some positive impact, with the high volume of water dispersing hotspots of bacteria away from shore.
Groundwater rise driven by climate change has also started to swamp home septic systems in Hampton Roads, allowing raw sewage pollution to enter waterways.
The other major climate impact is heat, which some bacteria and algae love.
“They thrive a lot of times when we have really, really hot temperatures,” Wood said. “And the number of days in a year that we have those is increasing. And so that by itself is driving some challenges.”
Combined, those factors are likely to cause more beach shutdowns in the future “if we’re not able to address the sources,” he said.
Climate patterns could also shift the types of organisms in the water, Smigo said.
Florida has dealt with beach shutdowns due to a species of harmful algae that thrives in warmer water, for example. While Virginia has thus far avoided this specific algae due to cooler waters, rising temperatures could help it spread north, she said.
You can check a map with the current status of beaches around Virginia on the VDH website.
