Programs, Events, & Volunteers

A group of volunteers and children
Photo: MD DNR

BioBlitz at Mallows Bay

Visitors examine wildlife caught in seine net activity Visitors examine wildlife caught in seine net activity presented by Maryland DNR. Credit: Sammy Orlando, NOAA

Mallows Bay-Potomac River National Marine Sanctuary is joining the City Nature Challenge! The City Nature Challenge is a global citizen science event with a focus on urban areas. Residents throughout the Washington DC metro area will be exploring local parks, backyards, and neighborhoods to observe the wild plants, fungi and animals that share our environment. As part of the challenge, Mallows Bay will be holding a BioBlitz, a free event where participants collect as many species observations as possible. By participating, you'll help scientists collect valuable biodiversity information and learn more about Mallows Bay!

Joining the BioBlitz is easy! Anyone with a cellphone camera and access to the free iNaturalist app can participate. Here's how:

  1. Download the iNaturalist App. Create a user account at
  2. Join the project on iNaturalist.
  3. Register for the BioBlitz (and receive a free t-shirt at check-in!)
  4. Join us at Mallows Bay on April 29th!

Event timing:

Saturday, September 9, 9am – 1:00pm


Mallows Bay Park (1440 Wilson Landing Rd, Nanjemoy, MD 20662)

Special activities:

  • 9am - Guided bird-watching hike led by the Southern Maryland Audubon Society
  • 11am - Guided general hike led by a local naturalist and environmental educator
  • All day - Seining for aquatic organisms with the Maryland Department of Natural Resources

When you arrive, look for the blue NOAA tent for check-in.

Contact for questions or concerns.
View a flyer with more information on the Bioblitz.

Things to bring:

  • Closed toed shoes
  • Seasonal clothes
  • Rain gear (just in case)
  • Water
  • Sunscreen/hat
  • A smartphone with iNaturalist downloaded

Become a Citizen Scientist!

a volunteer holding a water ph test kit
Photo: Potomac Riverkeeper Network

Come join the Potomac Riverkeeper to achieve the goal of a swimmable Potomac River. Although swimming in the river is currently prohibited, all users who come in contact with the water should be aware of bacterial levels and the potential for health concerns. The Potomac Riverkeeper is part of an international network of scientists and volunteers who sample and report the status through Swim Guide.

A new partnership between the National Marine Sanctuary Foundation and the Potomac Riverkeeper Network will develop a citizen science monitoring program at Mallows Bay focused on bacteria levels. This work will add to the body of weather and water data already available on the Mallows Bay water quality buoy that supports science and education as well as recreational and commercial uses. Potomac Riverkeeper will process the water quality samples aboard their floating laboratory Sea Dog. The monitoring results will be posted to Swim Guide and will help fill gaps in Potomac Riverkeeper's existing network along the river and contribute to a larger data set for more than 7000 beaches and waterways.

COVID-19 Update: Due to precautions associated with COVID-19, Potomac Riverkeeper is not able to host in-person training sessions for new volunteers. However, they are working to develop an online training module. In the interim, they will be asking their network of trained volunteers to conduct sampling at Mallows Bay this season with the hopes of adding new volunteers later in the year. Please continue to check this page for updates.

Be a Volunteer

the view of a sunrise from a kayak
Photo: Stephen Badger/MD DNR

All national marine sanctuaries rely on the energy and passion of volunteers. There are so many ways to be involved. Please consider adding your name to those who make it happen at Mallows Bay-Potomac River National Marine Sanctuary by contacting Sammy Orlando, Chesapeake Bay Regional Coordinator, at

Force Blue

Force Blue is a volunteer organization that unites two worlds by helping veterans and helping the environment. A team from Force Blue volunteered to conduct an initial survey of the subaquatic vegetation in Mallows Bay – Potomac River National Marine Sanctuary. The data that they collected provides much needed information on the various species and the health of the sanctuary.

National Marine Sanctuary Foundation

National Marine Sanctuary Foundation Logo

The National Marine Sanctuary Foundation enhances national marine sanctuaries in their goal to protect essential U.S. marine areas and to ensure a healthy ocean.