We test the lake water for two main reasons:

1.      We are concerned about the health and safety of the water, and

2.      We are required by the county health department to test for bacterial contamination if we allow swimming in our lake. 

Compliance is voluntary and the specific requirements are not stipulated.  When we publish our water test results, stating that they are “OK” or “within the guidelines”, that simply means we can continue to allow swimming in the lake.  It does not guarantee that the lake is safe or free of contamination. 

For one, there is a lot of possible bad stuff that we simply do not have the resource to test for.  For another, we don’t take tests often enough to have meaningful timely information.  You must always use your own best judgment about the condition of the lake and whether it is fit to swim or wade in.  Swimming pools and drinking water get tested at much closer intervals.  As an open body of water, our lake is subject to natural and manmade conditions in its watershed.  That is an area of about 4 square miles, most of it not in the LFA neighborhood.

Our test monitors something that you cannot see or smell.  Since the lake refilled after the last restoration in 2003, all of our tests have been OK.  This was not always true before then.  Some of the worst results we ever got were in sparkling, cool, (relatively) clear water.  On the other hand, hot fetid August swamp water has usually passed with flying colors! Our test is no measure of the aesthetic quality of the lake water.

The test we use is Fecal Coliform, EPA method 126.  This looks for a bacterium that lives in the gut of warm-blooded animals.  It is not particularly nasty, but in high concentration it causes skin and eye irritations and can cause digestive system disturbances.  It dies in the lake, it does not grow or reproduce there, so we are observing its dilution and demise.  This test is used by OWASA on University Lake (our drinking water supply), and the results we get are usually comparable.  We are very fortunate to have an urban lake that has remained unpolluted.

Fecal Coliform is an indicator organism.  This means that it is relatively easy to find and culture and it is found in differential amounts that produce meaningful information about how much contamination is present and how persistent the source is.  Other nastier bugs, like Giardia, are associated with some of the sources of fecal coliform bacteria.  Giardia is easier to miss because it is usually found in much lower concentration.  Directly testing for Giardia produces less reliable results.  This applies to many other types of contamination. 

At present, our testing monitors the “big-picture” health of our lake and its tributaries.  We take three samples, one between the docks near the swimming beach, and one at each tributary entering the lake.  This gives us an indication of the source if we get any bad readings.  If we do get bad readings, we shift to a different testing interval until the readings return to the “safe” range. 

Before the restoration, there was a problem with a sewer line upstream of the lake that regularly overflowed after a heavy rain.  OWASA was in the process of fixing this and made their water analysis facilities available to us in order to keep up with any possible contamination that could reach our lake. 

We began our relationship with OWASA about 10 years ago, immediately after Hurricane Fran, when we had a lot of stranded neighbors using the lake and no way to get water samples to our testing facility in Burlington.  Over the years, while the sewer project was underway, we learned a lot about the water chemistry of our lake and the behavior of our watershed via our contact with the professional staff at the OWASA lab.  That all ended when the sewer project was finished and declared a success.  This happened at about the same time we drained the lake to make our first planned attempt at a sustainable restoration.

While we had access to the OWASA facilities, we tested more frequently, and even considered setting up a flag system at the lake park to indicate the current water test status.  We decided not to do this for the same reasons I mentioned at the beginning of this article:  Our tests are not frequent enough or rigorous enough to guarantee the safety of the lake water.  It is not practical to do that, even if we had the money for the analysis and paid staff to take frequent samples.  The responsibility for deciding the lake is safe ultimately belongs to the LFA members that want to take advantage of our common asset.

We can tell you, with about the same degree of confidence you get when using any freshwater lake swimming beach at a state park, that it is not chronically polluted.  If it is polluted and we become aware of this, you will be notified at the lake park and via this website.  We get notices of known spills in our watershed from OWASA.   If the spill relates to OWASA-controlled sources, they take their own tests and share the results with us.

None of this protects you from any instantaneous or very localized yuck that could wind up in our lake.  If you see anything that concerns you, please let me know, and I will share it via this website or communicate it to the staff or board members as appropriate.