south river monitoring

 View Operation Clearwater Bacteria summer results through the interactive Swim Guide map below.
 Download the SwimGuide App Here!

Click here to see map.

Past Summer Bacteria Sampling Results:

     2017 Data [pdf]  2016 Data [pdf]
 2015 Data [pdf]  2014 Data [pdf]  2013 Data [pdf]  2012 Data [pdf]
 2011 Data [pdf]  2010 Data [pdf]  2009 Data [pdf]  2008 Data [pdf]
 2007 Data [pdf] 2006 Data [pdf]   2005 Data [pdf]

2004 Data [pdf] 

The South River Federation is a participant in Operation Clearwater, a bacteria testing program for community waterfront recreational areas on the South River that runs from May through Labor Day. The program provides waterfront communities on the South River with regular updates of the microbial water quality at their waterfront recreational areas. Operation Clearwater was started by the Severn River Association and is a collaborative effort with Dr. Tammy Domanski, a Professor of Biology at Anne Arundel Community College, aimed at providing timely public health information to participating communities and helping to identify times when it may be inadvisable to swim.

Anne Arundel County Health Department

The Anne Arundel County Health Department advises that after a rainfall, all Anne Arundel County beaches are under a no swimming/no direct water contact advisory for 48 hours due to predicted elevated bacteria levels from rainwater runoff and increased health risks. For more detailed information and to receive E-Alerts regarding water quality, sign up for the Health Department's E-Alert System:

What are fecal bacteria?

OPERATION CLEARWATER monitors water quality by enumerating a group of bacteria collectively known as the Enterococci. These bacteria, like the fecal coliforms counted in the past, are associated with fecal waste of warm-blooded animals, birds and mammals. These bacteria themselves are not harmful to swimmers but they do indicate the presence of recent fecal contamination of water.

When the number of Enterococci exceeds 104/100 ml, there may be other microorganisms present in the water which could cause illness, such as gastroenteritis or ear infections. It is generally recommended by the U.S. Environmental Protection Agency not to swim in water containing enterococci counts that have an average value exceeding 35/100 ml or a single sample result of more than 104/100. Thus counts that exceed 104/100 ml are highlighted in red on our web site. For more information about the EPA method and interpretation of results, visit this EPA document.

The counts of bacteria in water are always variable. The number of Enterococci/100 ml will vary greatly depending on rainfall. Once we have received enough rain to cause substantial overland flow into our creeks and rivers, generally about one-half inch of rain, bacterial counts will tend to rise sharply and will remain high for 24-48 hours. This is especially true in areas where runoff flows down streets directly into creeks and rivers. For this reason, rain data are included in this report when we have had at least 0.5" of rain within the watershed 24-48 hours previous to sample collection. Of course, summer thunderstorms are notoriously spotty. As we measure rainfall in Annapolis, a brief but intense storm in Crownsville or Edgewater may not even be recorded.south river operation clearwater

Samples are collected on Wednesday mornings between 7 am and noon at a location of your choosing at the community's waterfront facility. Data are posted on the Federation website by Friday morning. If the number of enterococci exceeds 104/100 ml, Operation Clearwater Community Representatives are notified promptly by phone or email.

Registration for 2019 Operation Clearwater will start in April of 2019.

In 2018, a 14 week schedule costs $450 and ran from May 23rd through September 5th. Updated rates and dates will be posted in 2019.

Contact the Federation office at 410-224-3802 or This email address is being protected from spambots. You need JavaScript enabled to view it. us for more information or to sign up for sampling.

2014 Bacteria Results: (Greater than 104 cfu/100 ml are considered elevated bacteria levels.  These samples are highlighted in red)