Dunlap Lake water samples taken on May 18 showed the lake is safely under the danger level for contaminants for swimming this weekend, but it might be best to avoid shallow parts of the south end.
A moderately high level of E. coli was present near the south end of the lake, off the end of Lotus (which has happened several times before when water was tested during or right after rain as it was May 18). Up by the dam and near the lake’s center off of the end of Hollyhock were normal for this lake.
E. coli results are measured as the number of colony-forming units (cfu) in 100 ml of water. E. coli concentrations in deep part of the north end of Dunlap Lake this week were 10 cfu per 100ml. The mid-lake sample contained 30 cfu per 100ml. The south end had 100 cfu per 100ml.
To put this in perspective, the Illinois Department of Public Health will close a public beach to swimmers when E. coli is present at 235 cfu per 100ml. Dunlap Lake was less than half that level.
Nitrogen and phosphorus, nutrients that promote algae and aquatic plant growth were also measured. The dam and mid-lake samples were similar to previous years. The south end was slightly lower than past years.
Water testing results are posted on the website at www.dunlaplake.org/water-testing/. The water will be tested again before 4th of July.
View the full report here
All water quality data is maintained here.