Blue Marsh Lake Algae Advisory

Published July 18, 2019
Blue Marsh Lake Algae Advisory

Blue Marsh Lake Algae Advisory

The U.S. Army Corps of Engineers’ (USACE) Philadelphia District is asking Blue Marsh Lake visitors to be aware of the potential for harmful algae at the lake.

Heavy rainfall and significant runoff conveys nutrients to the reservoir. When followed by hot weather, blue-green algae can thrive and multiply. Blue-green algae, also known as cyanobacteria, are microscopic organisms found naturally in all types of water. In warm, nutrient-rich environments, cyanobacteria can multiply quickly, creating blooms that spread across the water’s surface.

To protect yourself, your family and your pets from blue-green algae blooms:

  • Don’t swim, water ski, or boat in areas where the water is discolored or where you see foam, scum, or mats of algae on the water’s surface.
  • Do not allow children or pets to play in or drink scummy water.
  • If you do swim in water that might contain harmful cyanobacteria, rinse off with fresh water as soon as possible afterward.

USACE is working with the Pennsylvania Department of Environmental Protection to conduct sampling and testing at different locations at Blue Marsh Lake. Currently, test results show toxin levels associated with blue-green algae are below Environmental Protection Agency (EPA) recommended recreational water limits. However, results show significant levels of blue-green algae and conditions can worsen quickly with hot weather.

Visitors should follow the below Centers for Disease Control guidelines and remain vigilant at Blue Marsh Lake and when visiting other bodies of water.

USACE will continue to conduct testing at different locations at Blue Marsh Lake. For additional information, please contact the Park Office at 610-376-6337. 


Scott Sunderland

Release no. 19-013