Water Testing of Lake Roaming Rock

By David Ernes – Lake Management Committee

We are definitely seeing signs that the winter has left us and we can begin to enjoy our lake for yet another fun-filled season of swimming, skiing and kayaking. This also marks the start of the Lake Management Committee’s (LMC’s) efforts to monitor the water quality to insure that it is safe for these activities. In past articles, we have discussed the issues related to algae blooms and the toxins that may sometimes be present. The LMC coordinates testing for these toxins to make sure that water at the two beaches is safe to enjoy. These two areas are where the greatest number of people swim at any one time.  It should be noted that no result from the past three years has ever exceeded the guidelines set forth by the OhioEPA. We hope that this season will be the same. It should also be noted that many private lakes only test their beaches for bacteria, and not algal toxins. Should the levels of toxins or bacteria be exceeded, signs will be posted to warn of high levels.

This year we will be adding an additional type of testing. If you have used the many public beaches across the country, you may have encountered signs warning of bacteria contamination. This is based on testing for the presence of fecal coliforms, which are bacteria commonly found in the gut of most animals. Some, but not all, bacteria of this type can cause illness in humans. The LMC has decided to conduct testing for bacteria to insure that the levels are safe, again focusing on the two beaches. For bacteria, the results will be reported as “cfu/100 mL”. These units are strange and do not have any real correlation with concentration. For those geeks out there, the units represent “colony forming units per 100 milliliters of water”. A volume of 100 mL is roughly equivalent to a third of a cup. The current OhioEPA guideline for posting advisories for bacteria is 235 cfu/100 mL.  This type of testing is routinely done for Ohio’s many public beaches. On the Ohio.gov web site, you can see the results from surrounding public beaches in their BeachGuard section.

If you see these signs, it will be your responsibility to decide if it is appropriate to swim in the water or to “take a day off” and use the pools. As with the toxins, those at the highest risk are the young and the “more mature” residents. In addition, since one potential source for bacteria is from run-off, the levels are often highest just after a significant rain event.

BE LAKE RESPONSIBLE