Algae Blooms Detected In The Potomac River

They could be due to the dry weather conditions.

Photo from Interstate Commission On The Potomac River Basis

Frederick, Md (KM) The hot, dry weather we’ve been experiencing could be the reason for algae blooms spotted along the Potomac River. That’s according to Gordon Selckmann, the Associate Director of Aquatic Habitats for the Interstate Commission on the Potomac River Basin

He says algae have been seen at the confluence of the Potomac and Shenandoah Rivers near Harpers Ferry, West Virginia. “Some of the more impacted regions are from the confluence of the Potomac River to the Shenandoah downstream and to just across the fall line into the tidal Potomac,”: he says.

Selckmann says this could be the result of the lack of  rain we’ve been experiencing this summer. “Generally, slower moving, stagnant water that allows these algae to basically take a hold and not break away in higher flows,”: he says. “So a scouring heavy rain will sweep these away.”

The Maryland Department of the Environment has placed western Maryland, including  Frederick County, under a drought watch due to lack of substantial rain.

The Commission says these algae blooms can be a common sight during the hot and dry periods of the late summer., but there is evidence they are becoming more common due to climate change.

ICPRB says aquatic biologists have been busy recently exploring the blooms of the North and South Branches of  the Potomac, trying to determine where these blooms are, and why they are showing up so soon.

In addition, the ICPRB says some of these algae blooms can produce toxins known as cyanobacteria that sicken people and animals. Selckmann says it’s best to keep yourself, your pets and your livestock away from the Potomac.

He also says there are several ways to determine if algae are affecting the Potomac River or any other body of water. He says if the waterway has a bad smell or is discolored, that could be a sign of an algae bloom. “Generally, keep an eye out for foam, scum, agla mats–those things that are collecting on root wides and log jams–and that paint-like sheen on the surface,” he says.

A fourth sign of an algae bloom is dead fish or other animals washing up along the beaks of a river.

Selckmann says the algae will wash away with heavy rainfall.  He points to the example of Hurricane Ida in 2021. “Shenandoah had better than 50-miles closed for human health concerns. When Hurricane Ida came up the coast, it washed everything out within a day. And we were trying to chase the blooms to see where they would re-establish, and they were kinda gone for the season once that was done,” he says.

By Kevin McManus