Massive Algae Bloom Impairs Recreation on Cacapon River


Long, stringy, dense, and slimy—there’s not much to like about the massive green algae bloom that’s plaguing the Cacapon River near Yellow Spring in Hampshire County. 

This overgrowth of stringy algae, known as filamentous algae, stretches for several river miles. In the summer months, the largest patch is 3 miles long and covers up to 80 percent of the river, making swimming, fishing, and paddling nearly impossible. 

The West Virginia Department of Environmental Protection (WVDEP) recently deemed this algae-affected portion of the Cacapon River to be “recreationally impaired.” For the first time ever, our notoriously healthy river has made WVDEP’s list of impaired streams in the state. Thankfully, unlike other varieties of algae, filamentous green algae is not toxic to our river’s waters. It’s considered more of a nuisance than a toxin. 

What’s causing the stingy algae to take over? The simple answer is pollution. Typically, pollution in the form of excess nutrients, such as nitrogen and phosphorous, promote this type of algae overgrowth. Yet, after studying the algae bloom for several years, WVDEP and the Interstate Commission on the Potomac River Basin (ICPRB) concluded that there is no direct evidence of a specific upstream pollution source. This year, they’re expanding the water testing locations and frequency and exploring innovative ideas to help identify the cause. 

In the meantime, if you’re planning a paddling trip from the Yellow Spring public river access site to the Yellow Spring North one, be aware that you will likely encounter some long, stringy algae that will be difficult to navigate.