Dry weather made for low bacteria counts in most swimming areas throughout the area as of Wednesday, meaning possibility care-free weekend bathing. But as I write this Friday morning, possible thunderstorms are forecast for later today and tonight around the area.
Bacteria levels generally are lower than previous weeks across the region, although water in about 10 spots still exceeded government safety levels. The county has issued water advisories for some, but not all of the areas. For a map of the hotspots go here. Here's the list of these week's unhealthy swimming spots (explanation of the numbers, and background information is below):
CHESAPEAKE BAY
Franklin Manor – 113 *
STONEY CREEK
Orchard Beach – 187*
SEVERN RIVER
West Severna Park – 140**
Olde Severna Park – 240**
MAGOTHY RIVER
Cape St. Clair, Lake Claire – 251 *
Magothy Manor – 134**
SOUTH RIVER
Almshouse Creek/Pine Wiff – 428**
Warehouse Creek/South River Park – 610**
RHODE RIVER
Holly Hills – 186**
Riverclub – 185*
Riverclub Dock – 134**
*County monitoring
** Volunteer monitoring
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. See Water Quality Fact Sheet. All the spots on the list above exceed safety levels.
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, here for South River, and here for Rhode/West River.
Usually, volunteers report their test results by Thursday afternoon of each week. The county takes longer, usually till Friday morning at least. I waited this week for the county numbers.
Bacteria can make you sick if ingested, or in some cases if touched with an open wound.
Storms increase bacteria in the water as runoff carries pollution from the urban and suburban landscape. The bacteria generally can live for 48 hours in the water, so unless the water tests are conducted within that time they are essentially worthless.
So follow the rule of thumb of county and state health officials and avoid swimming and contact with local water or 48 hours after a significant storm.
By the way, many of the volunteer testing work is done by Watershed Stewards. If you want to become a steward they would love extra help.
Have a fun and safe weekend.
