Nutrients and Filamentous Algae in West Virginia

What is Filamentous Algae?

Filamentous algae are connected algae cells that grow and form long threads or filaments When growth is excessive, large mats can form that stretch from the river bottom to the surface and cover significant portions of a river reach. The term “Filamentous Algae” refers to any number of species that can be found in rivers and streams. There are numerous species of algae that are native to West Virginia and that can be found at any one location.

Filamentous Algae

Impacts of Filamentous Algae Blooms

Filamentous algae blooms can interfere with designated uses of a river - typically water contact recreation and public water supply. The images display the extent of the problem in some impacted rivers.

If entities supplying public drinking water have an intake located in an area of a filamentous algae bloom, they commonly receive complaints about the odor and/or taste of the water, requiring additional treatment and expenditures. Recreational activities, such as swimming and fishing, can be impacted by the excessive algae, and lessen one's ability to enjoy state rivers and streams.

Cacapon Algae
Greenbrier Algae

Recreational Activity and Filamentous Algae in West Virginia Streams

Questions have been raised concerning how filamentous algae in West Virginia streams and rivers impacts and ultimately may limit recreational activities. Activities like swimming, fishing and boating support a significant tourism industry and are a critical economic driver in numerous regions of the state. As important as this issue is, it is very difficult to adequately measure and quantify impacts. To address this question, DEP sponsored a survey to measure the level of tolerance residents have to varying amounts of filamentous algae in state streams. The survey was conducted by the research firm Responsive Management, and a copy of the final report is provided.

What Causes Filamentous Algae to Bloom?

Nutrients - primarily nitrogen and phosphorus - when in excess are directly available and allow normal background levels of algae to grow into excessive blooms. Flow conditions and river water chemistry also influence when and where a bloom may occur. Sources of the excessive nutrients vary by watershed, from point sources such as waste water facilities to non-point sources including urban or agricultural runoff.

What is the DEP Doing to Address Filamentous Algae Blooms?

DEP is monitoring numerous rivers in the state for filamentous algae blooms, including the Greenbrier, Tygart, South Branch of the Potomac and the Cacapon rivers. The Watershed Assessment Branch (WAB) has developed Standard Operating Procedures (SOPs) for measuring filamentous algae in streams and rivers. The SOP can be found in the Periphyton/algae collection procedures section of the SOP document. WAB has also completed numerous special studies on the algae issues in the Greenbrier River and these studies can be found on the Special Studies web page. When adequate information is collected that determines blooms are impacting the uses of a stream or river - DEP will consider listing the waterbody as impaired and putting it on the 303(d) list. The DEP has developed a listing methodology for determining algae impairments that can be found in the 303(d) Listing Methodology for Filamentous Algae Blooms. Once listed, DEP will develop a TMDL or take other actions to address the sources of pollution contributing to the algae blooms. Annual stream nutrient-algae monitoring and assessment reports can be found on the Nutrient Reports web page.

Greenbrier Algae Sampling

What can I do if I see Algae Blooms?

DEP staff cannot be everywhere, and input from the public can greatly assist in our understanding of filamentous algae blooms, including when and where they happen. So if you see something that resembles a filamentous algae bloom, here is how you can help:

  1. Document the time and place - the more specific the description the better, but even a general location is helpful.
  2. A picture speaks volumes - the more the better.
  3. Let us know what type of activity you were doing; swimming, fishing, boating, kayaking, etc. Did the algae impact your activity?
  4. Contact DEP Staff

Contact Information

James P. Summers, Environmental Resources Analyst
West Virginia Department of Environmental Protection
Division of Water and Waste Management
601 57th Street, SE
Charleston, WV 25304
Phone: (304) 926-0499 x43890