Submerged Aquatic Vegetation Reporting

Each year the Virginia Institute of Marine Science uses aerial photographs to calculate acres of underwater grasses – known also as submerged aquatic vegetation (SAV) – that occur across the Chesapeake Bay and its tidal tributaries. Ground surveys completed by citizen volunteers are used to complement these aerial photographs, by providing information on SAV species, density and other observations. These ground surveys help scientists collect data for tracking underwater grass health in the river. Ground surveys from non-tidal areas of the James River watershed help fill a gap in information that is not currently monitored by other agencies or organizations.


What can you do? Help monitor the recovery of SAV!

Volunteer surveys can occur anytime from May to September. No monitoring or science background is required. Volunteers already participating in the RiverRats Program may count their monitoring work as an Action Project.

The State of the James is a report card summarizing ongoing efforts to bring the James River back to full health. This comprehensive assessment of the health of the river is published every two years. View the report to see how the river’s health has changed.

What are underwater grass beds?

Submerged aquatic vegetation (SAV) grows in shallow waters across the James River watershed and are the basis of important and productive ecosystems. They provide a number of water quality benefits by trapping nutrients and sediment, producing oxygen and absorbing wave energy. These plants provide important sanctuaries for crabs and fish, and SAV serve as a food source for waterfowl. Approximately 20 species of SAV occur in the James River watershed, with different species occurring in fresh, brackish or seawater.

Because underwater grasses require sunlight to grow, their presence can be a positive indicator for water clarity. Clean, clear water supports grass growth, which in turn enables crabs, fish, waterfowl and many other species to thrive. Murky water, clouded by sediment runoff or algae blooms, can prevent underwater grasses from reaching full capacity. Human development and pollution severely reduced SAV beds, which once covered several thousand acres within the tidal James River watershed. But in recent years, thanks to investments in pollution reductions, underwater grasses have begun to make a comeback. Between 1980 and 2015, acres of underwater grasses expanded from nearly zero to 2,000 across the tidal James River watershed, largely because of improvements to water quality. You can read more about trends with James River underwater grass beds in the State of the James Report. 

How do you get started?

Download the Water Reporter app from the Apple Store or the Google Play Store. Water Reporter makes it quick and easy to submit a report when you are out on the water.

Once you download the app, create your free Water Reporter account, and join these two report groups: “James River Association” and “Chesapeake Bay SAV Watchers.

Each time that you see an underwater grass bed in Virginia’s James River or any of its tributaries (both fresh and brackish water), collect a representative strand of SAV. Use your phone to photograph the specimen against a light colored background at the site where you found it.

Upload the photo to Water Reporter while recording your location in the app. Type #SAV into the comment area, and then submit. Move to a different grass bed and repeat! Try to report as many beds as you can.

Click here for examples of #SAV reports in the Water Reporter app.