Mapping the Reemergence of Bay Grasses

R. John Dawes
Aug 24, 2017 · 6 min read

Underwater Grasses, commonly referred to as submerged aquatic vegetation (SAV) are a cornerstone indicator of a healthy Chesapeake Bay. These beds not only provide the food and shelter required to enable forage fish, blue crabs, and iconic Bay species to thrive but also add oxygen to the water while absorbing nutrient pollution. SAV beds also play a significant role in reducing shoreline erosion by helping suspended sediment settle slowly to the bottom of the Bay.

Historically, researchers estimated that there were approximately 200,000acres of underwater grasses that grew along the shorelines of the Bay and its tributaries. However during a large influx of nutrient and sediment pollution caused by a variety of human induced factors, many of these beds were weakened or completely eliminated by the 1980s. In 1984, the Chesapeake Bay Program estimated that SAV beds dipped to an alarmingly low total of only 39,959 acres. To reverse the sharp decline, the

Chesapeake Bay Program partnership and many other on-the-ground practitioners began adopting a variety of scientifically vetted management approaches to bring these beds back to previous levels. These approaches outlined in the Bay Program’s Submerged Aquatic Vegetation Outcome Management Strategy are as follows:

  • Improving Habitat Conditions
    Many habitat conditions prove difficult to manage because our environment is incredibly dynamic. However, water clarity is one of the many factors in the Bay, that can help catalyze resurgence of SAV beds. To this end, restoration practitioners have worked to target replanting and protection projects that seek to enhance and propagate areas with suitable SAV habitat conditions. For example one could re-plant the appropriate species in favorable, local water quality conditions. Other strategies include advocating for management practices that alleviate climate change stressors such as minimizing shoreline hardening/modification that allow inland migration of SAV as water levels increase. This even extends to replanting efforts by introducing heat tolerant species in areas of the Bay that are warming.
Water Starwart shared by Brooke Landry on Water Reporter
  • Human Impacts
    As expected, human activity is correlated to Bay grass decline through direct activities such as dredging, propeller scarring, fishing and aquaculture practices. Indirect effects consist of localized water quality degradation — such as shoreline alteration or sedimentation from changes in land use. In-water activity, like clam dredging, also influences the health of the SAV bed. Effective management strategies to curb human impacts consist of education, outreach, and regulation.
Wild Celery shared by Ben Watson on Water Reporter
  • Restoration Science
    Replanting efforts have proven to be difficult due to the overriding factors of low water quality in the Chesapeake Bay. That said, by studying the best case habitat scenario that allows various species of propagules to succeed, practitioners can prioritize and ensure every possible effort is made for that planting to proliferate. This strategy assumes that continued seed and propagule restoration research will contribute to a growing knowledge base and serve to keep expert staff in agencies and institutions as well as provide opportunities for public involvement and education.
Vallisneria shared by Beth Wasden on Water Reporter

Tireless management efforts within these three strategies are yielding results. In 2016, preliminary data indicates an estimated 97,433 acres of underwater grasses were mapped in the Chesapeake Bay. This equates to roughly 7,433 acres more than the Chesapeake Bay Program’s 2017 restoration target and 53 percent of the partnership’s 185,000-acre goal by 2025.

Annual Aerial mapping of Bay grass beds in the Chesapeake Bay yields the most accurate and authoritative data that can be used to track and map the growth or decline of SAV. This incredible effort has been spearheaded by the Virginia Institute of Marine Sciences (VIMs) dating back to 1978 and fuels information products that can benchmark progress and tracking toward watershed implementation plan goals. Working in collaboration with VIMS, the Chesapeake Bay Program, and the project leads from the Habitat (Brooke Landry) and Fisheries (Tom Idhe) Goal Implementation Teams, Chesapeake Commons supported this effort by deploying its growing community of Water Reporter users to crowdsource local observations of SAV throughout the Bay Watershed and its tributaries. Using the WaterReporter mobile application from boats and docs throughout 7 sub watersheds in the Chesapeake Bay, volunteers shared more than 15o geo-referenced images and species information on local SAV sightings. Researchers use the volunteer data to help ground-truth SAV bed flyovers as well as provide species information.

Brooke Landry at Maryland Department of Natural Resources sums up the niche these citizen data fill as follows:

We have the acreage data from VIMS, but very ad hoc species data. We’re hoping this data will allow us to track how species are moving and changing around the Bay. Higher species diversity is linked to resilience, so we’re hoping as acreage recovers, so will diversity. And where diversity doesn’t recover, we’ll be able to pinpoint areas for restoration based on the data the volunteers are collecting.

The Water Reporter Platform as a whole is built on an a highly flexible Application Programming Interface (API) that makes the data and feature sets of the system almost infinity scaleable. Currently the data is being shared with VIMs for their mapping efforts, flowing into the Chesapeake Bay SAV Watchers Group in Water Reporter, and even powering this simple, realtime map we spun up so you can explore what our volunteers are observing out on the water.

It’s also important to note that in a political climate where state and federal funding is extremely uncertain, volunteer networks and the data they collect become invaluable. Believe it or not, SAV outside of the environmental space is not exactly a mainstream topic. But by appealing to individuals through their love to get out on the Bay, desire to connect with their local watershed group, and providing a clear call to action of what they can share via Water Reporter, we are integrating this topic into daily routines and habits along with our technology. Long term, the Commons’ role goes beyond helping support scientifically rigorous data with crowdsourced initiatives. Our organization’s role includes connecting everyday people with leveraged technology that help improve and build greater awareness of environmental improvement and initiatives. At the end of the day we are driven by putting the type of technology into people’s hands that inspire them to get involved in promoting and taking action to improve water quality right in their local watershed.


  1. Download the Water Reporter App for IOS or Android and setup your account
  2. Join the Chesapeake SAV Watchers Group in Water Reporter
  3. Use the app to submit a photo, comments, and location of where you see #SAV

Water Reports

A collection of stories written and curated to highlight the applications of Water Reporter, share helpful information, and inspire you to find your own way to use our platform to move us all toward healthy waterways.

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R. John Dawes

Written by

Founder/Executive Director of Chesapeake Commons.

Water Reports

A collection of stories written and curated to highlight the applications of Water Reporter, share helpful information, and inspire you to find your own way to use our platform to move us all toward healthy waterways.

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