Virginia DEQ continues to test parts of the Shenandoah River with harmful algae bloom

Published: Jul. 29, 2021 at 6:06 PM EDT
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SHENANDOAH COUNTY, Va. (WHSV) - Almost a week later, the Virginia Department of Health is still asking residents to not swim in parts of the Shenandoah River due to harmful algae blooms.

Researchers with the Virginia Department of Environmental Quality (DEQ) were out on the river on Thursday near the boat landing at Strasburg Town Park to take samples of the river.

According to the Virginia Department of Health, the North Fork of the river is experiencing a benthic harmful algae bloom (HAB) caused by cyanobacteria.

Coming into contact with this algae can cause skin rash and gastrointestinal illnesses, such as upset stomach, nausea, vomiting, and diarrhea. Cyanotoxins, including those identified at this location, can be fatal to dogs and other animals when ingested.

“See how it forms these mats over here, it looks really scummy and yucky and that’s really what the advisory is advising people to stay away from,” Tara Wyrick, with Virginia DEQ said.

Wyrick says these blooms are nothing new and a cause for them is related to low river levels and rainfall.

“We haven’t gotten a lot of rain lately, the river levels are pretty low so all of that means there’s a great breeding ground for algae,” Wyrick said.

She said the algae will eventually go away naturally and only affects parts of the river but overall the North Fork of the river is healthy.

“Our biologists actually measure that by looking at not only fish but also the benthic macroinvertebrates the bugs that live at the bottom of the stream,” Wyrick said. “So they provide the bottom of the food chain and so when they’re healthy we know that the rest of the ecosystem is pretty healthy.”

The area of the river where algal mats should be avoided can be seen on an interactive map at

On July 13 and July 19, the DEQ collected samples at two sites on the river in the Strasburg area which led to the advisory.

The river serves as the raw water source for the Town of Strasburg, which provides public drinking water for a population of approximately 6,495. Since the bloom was discovered, the Town of Strasburg has adjusted the treatment protocol and increased monitoring. VDH has observed no evidence of impacts to drinking water at this time.

You can read the full VDH advisory by clicking here.

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