How do you tell whether the river bottom at 4 meters depth is sand, mud, rock, concrete or shell?
You can listen to the sounding pole. It’s a crunchy sound when you hit sand.
This month, SRA’s Oyster Committee Co-Chair, Ted Delaplaine, taught us how to use a sounding pole to ground truth what we “see” on the side-scan sonar that we also use to assess bottom conditions at the Severn River’s historic oyster bars.
In the picture at right, Ted is “sounding” the bottom at Eaglenest Point in the Round Bay.
This was once a thriving oyster reef and could become a possible future home to a restoration reef – if conditions are good. So far, the news is good. Eaglenest Point features a hard sandy bottom that could once again support oysters.
We’re surveying historic oyster bars to identify the best locations to create new oyster reefs in the Severn River. It’s part of SRA’s goal to re-populate the river with billions of oysters so they can clean and filter the river like they did in the good ol’ days.
We are using a mix of old and new technologies – side-scan and downscan sonar, sounding poles, underwater drones and scuba divers – to survey the bottoms of the 25 oyster reefs that once thrived in the Severn River – 100 years ago.
SRA’s Water Quality Monitoring data over the past three years shows that oxygen and salinity levels here are on par with areas where oysters are thriving on restoration reefs!
Next month we’ll work with our partners, Black Girls Dive Foundation in Baltimore, to use an underwater drone and scuba diving teams to add visuals to our sonar and pole findings.