Clark Lake beach is tested once a week for E.coli from May through September. An advisory is posted if the value exceeds 235.  The beach is closed if the value exceeds 1000.

The value for water collected on 7/20/2022 was 1299 and the beach was closed until a follow up sample on 7/23/2022 was reported as acceptable. Results since 2018 were reviewed and only three values in that time were over 100 with the highest being 178. Thus, this is a very rare event for Clark Lake. No further action is necessary unless future results reveal more elevated values.

 

E. coli itself may not cause any problem but it is an indicator of risk including other water born viruses and bacteria. The E. coli level of 1000 corresponds roughly to a risk of 14 cases in 1000 people in the water. Most common problems are GI but there are a few skin and respiratory problems that could develop.

The ERIC lab at UW-Oshkosh is contracted by the County to do weekly E coli testing at the Clark Lake beach. This year they have been testing on Wednesday mornings. The most recent result is posted at https://www.theswimguide.org/beach/8609 the same day.  

The test results are shared with the DNR with current and past values available at https://dnr.wi.gov/beachhealth/.  Results on the DNR site may not be posted for 1-2 days after the testing. As an example, the current event sample was collected on July 20^th, the DNR logged the advisory on the 21^st of July and didn’t send out the e-mail notice until July 21^st .

There is an article in the Jun 23, 2022 Peninsula Pulse about a Door County program to add electronic monitoring signs to give more timely notice  beaches.