The Health Department has had the opportunity to have a discussion with Save the Sound’s Bill Lucey about their concerns regarding a perceived change in water quality at Jennings Beach between the 2015 and 2016 swimming seasons. We always welcome the opportunity to work together to look at and consider additional ways to improve water quality at our beaches. The Town of Fairfield has a long history of working to improve the water quality of our rivers, streams, water bodies and coastal waters. Multiple town departments work together alongside state and other agencies collecting samples, studying results, conducting surveys, identifying and eliminating pollution sources as well as making infrastructure improvements; all with the goal of improving our water quality.
While we understand and can appreciate Save the Sound’s interpretation of the data, their report does caution about reading too much into such a limited year over year comparison. The data Save the Sound is using is actually from the samples collected by the Health Department. The chart below shows the average geometric mean for the samples collected at Jennings Beach since the year 2000 with a second thinner line being a running year over year average.
*lowest detection limit reported by lab is 10. Thin line is a running year over year average.
When we look at the data for Jennings Beach since 2000, you can see that, while the 2016’s results are higher than the 2015 results, they are similar to what was seen in 2014 and 2011 and are below what was seen in 2012 and 2001. We do not feel these year over year differences represent trends or changes in water quality but are more indicative of the normal variability of sample results and how much rainfall was experienced from year to year. Nearly all our elevated results are as a result of rainfall events, and more specifically, rainfall events that occur before our sample collection day. Simply put, the more rainfall events we have during the summer sampling season directly prior to our sample collection day, the greater the chance of elevated results. Studies conducted by the Health Department in conjunction with the state have indicated that a rainfall event of greater that 1.6” in a 24-hour period will most often produce elevated results at our coastal beaches. The Health Department monitors rainfall levels and will preemptively close the swimming areas when the rainfall is greater than 1.6” in a 24 hour period.
In looking further at the 2015-2016 difference, you can see that the 2015 results are below the 5 year average for the beach (and are actually below the 10-year average as well) while the 2016 results were above that same average; making the year over year increase appear more significant. In contrast to the 2015 to 2016 finding, you can see decreases of similar or greater magnitude between 2001 and 2002, 2004 and 2005, 2012 and 2013 and 2014 to 2015. In the same way that we don’t consider these trends or “improvements” in water quality, we don’t feel the 2015 to 2016 change represents a decrease in water quality. When looking at this seasons results, the 2017 results to date are identical to the 10 year average for the beach.
While Save the Sound’s interpretation of the 2015 and 2016 data do result in a change in how they grade Jennings Beach, we are confident for the reasons stated above, that there is no trend of decreasing water quality at Jennings Beach. The Town and its partner agencies will continue the work to improve water quality at all our beaches and welcome the opportunity to work with Save the Sound in doing so.