By each Friday through the summer I plan to report which beaches, and other swimming or recreation areas in Greater Annapolis may be unsafe over the weekend because of high bacteria levels. I want to do this because I don’t think most people realize water that looks perfectly ok can be unhealthy. And unless you’re a geek about checking websites you might never know about the sweet swimming spot that’s not.
I hope next week to include a map of the weekly hot spots.
Each of the spots below as of Wednesday had bacteria readings above healthy levels. Check below the readings for what the numbers mean, and for background on this issue. I’ve used a V to show when volunteers provided the data. County inspectors provided the other numbers.
Admiral Heights, Weems Creek: 236 (County monitors are re-testing. If those second series of tests come out high, they will post warnings.)
Sunset Beach, Carrollton Manor: 120 (V)
Hendler Road: 122 (V)
Sullivan Cove (old drainage ditch in Severna Park): 3050 (V)
Brown’s Pond (near Manresa Drive): 206 (V)
Spa Creek (near the bridge):196 (V)
Mill Creek: 4600 (V)
Dividing Creek: 660 (V)
Harbor Hills: 166 (V)
Pine Wiff, Almshouse Creek: 824 (V)
Selby, Selby Bay: 130 (V)
The acceptable level for swimming and other direct water contact is determined by the U.S. Environmental Protection Agency, Maryland Department of the Environment and the Anne Arundel County Department of Health. For bodies of water that the Department samples weekly and biweekly, the acceptable level of enterococci bacteria is 104 or fewer bacteria colonies per 100 milliliters of water. For areas that are sampled monthly, the acceptable level is 158 or fewer colonies per 100 milliliters. Each of the beaches above are tested each week. See Water Quality Fact Sheet.
Both the county health department and a network of volunteers test over 100 public beaches and other areas around the county for bacteria. The results from the county tests are put online here, and for the volunteer tests here for Severn and Magothy rivers, and here for South River.
The county is good about posting signs if their inspectors find bacteria levels have climbed above federal safety limits. But you should also realize bacteria readings are almost always highest after a strong storm, and county water testers may not check at that time. So just because there’s no sign doesn’t mean the county has checked the area, and found it safe. The inspectors’ weekly or bi-weekly schedule may mean they arrive days after the water was bad.
The best rule of thumb—which the county makes clear on its website—is to avoid swimming or contact with “natural” water (not swimming pools) for 48 hours after a significant storm, say an inch or more of rain. That can be an average summer thunderstorm.
Stormwater washes animal and human waste from the landscape into nearby creeks and rivers: pet waste, waterfowl, waste from leaking septics or from sewer spills, manure and other sources. The bacteria in the waste can cause stomach ailments. Also, sometimes blue green algae that grow in warm, polluted water can produce toxins that can be extremely harmful to humans.
One important disclaimer. Both the county and volunteer monitors did their tests on Wednesday, May 30. High readings may have diminished by the weekend and the water may be safe. On the other hand, readings may have risen since then, especially if it rained. As I type this Friday afternoon, I’m watching storm clouds building up outside my window.
Thanks to Sally Hornor who heads up Operation Clearwater for all the testing by volunteers. They customarily test swimming and other areas which aren’t tested by the county, but about which residents want information.