The Magothy River Association (MRA) held its annual State of the Magothy event March 31 at Anne Arundel Community College, and there was plenty of news to report.
Dr. Sally Hornor explained that the Magothy received a 30% or a D for 2022, a minor improvement over the previous year.
That grade comes from an index that includes three criteria. First is the coverage of submerged aquatic vegetation (SAV), which are rooted plants that grow in shallows and provide fish and shellfish habitat, waterfowl food and oxygen. The second criteria is water clarity — do grasses have what they need to grow? Five teams of monitors measure water quality at 30 stations from mid-April to mid-October using Secchi disks. Lastly, MRA looks for dissolved oxygen, just above the bottom of the river.
“That’s where critters that can’t move, like oysters for instance, you know, once they’re settled on the bottom, they can’t travel,” Hornor said. “They can survive in less than five milligrams per liter, but five millimeters per liter or more is ideal for oysters and for fish, so this would be really good habitat if we could have that much oxygen in the deep water.”
Hornor attributed the poor water quality to sediments washed into the water and the growth of algae.
The Magothy has too many algae blooms because of too many nutrients, like nitrogen and phosphorus. Much of that comes from septic systems, Hornor said.
As MRA president Paul Spadaro explained, the organization is now using drones to spot stormwater discharges, which helps with construction monitoring, and to locate heron nests.
“Heron only nest in a certain kind of pine tree, and unfortunately or fortunately … wherever they poop it stays on the nest and it’s easy to see from the air.”
The heron habitat qualifies an area for a 1,000-foot protective buffer, so that gives the MRA another method of controlling development.
With that in mind, Brad Knopf talked about keeping development from having a destructive environmental impact.
“I always like to mention the clay particles because they will actually coat fish eggs, and as Dr. Hornor mentioned, they will also clog the gills. And not only that, they go through silt fence, so clay particles are really trouble.”
Knopf then showed a PowerPoint slide demonstrating, among other things, loads of nitrogen from construction, row crops and impervious surfaces. The statistics came from the Chesapeake Assessment Scenario Tool.
“Everybody thinks about agriculture being the big culprit and it is, but look where construction sites rank with those nutrients, especially nitrogen – enormous impact,” Knopf said. “What should be happening on those sites … is stabilized perimeter, stabilized interior with the soils, with straws or vegetation, and if you don’t have it set properly, you can see the damage that happens.”
He then showed slides of the poor water quality of Deep Creek.
MRA monitors the county website for new grading permits and visits active sites to check for silt fencing and stabilized entryway stone, bare soils or piles of uncovered soil, and evidence of runoff leaving the premises.
In zip code 21409 — which includes portions of Arnold, Annapolis and Cape St. Claire — MRA surveyed 55 sites over the last year. Eight of those required corrective action, a significant decrease over the previous year. Knopf said MRA uses direct communication with supervisors of county inspectors and rapid response to address problems.
Lisa Crafton also addressed the audience at Anne Arundel Community College, sharing details of oyster reef balls that were placed in the Magothy River in March.
“These reef balls provide surfaces for oyster spat to attach and grow while creating valuable underwater habitat and protection for small fish, crabs and other marine life,” she said. “Oysters help to filter the water and do some heavy lifting when it comes to keeping river and bay water clear.”
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