The swimming area at Grand Lake State Park remains closed after additional water quality tests showed the presence of unsafe levels of E. coli.
Those test samples, taken Monday, showed unsafe levels of E. coli and Enterococci.
Visitor Trenda Nelson says she's not concerned.
"I don't really think much about it," she said. "There's always a warning about something."
Grand River Dam Authority says the swimming area near Bernice isn't one of their usual testing spots but was tested after people reported getting sick at that location. Several people got rashes and stomach problems after swimming.
GRDA says that since an independent lab is testing the water to see if the E. coli is from human or animal waste, the beach will likely be closed until at least Friday regardless of what the latest testing shows.
"That's just for the Grand Lake State Park swim beach," said GRDA spokesperson Justin Alberty. "There are lots of other places on Grand Lake where you can go swim, have access to the water that are very much still open for business right now."
The GRDA ecosystems lab is testing water samples each day. It typically takes 24 hours to get results.
"Because of the continued elevated levels of E. coli and Enterococci in the area we will continue to be cautious and keep public safety as the priority," Alberty said in a news release.
"At the same time, we are still actively investigating to determine the source for these elevated levels."
There are 18 different sites where GRDA tests water quality every two weeks during the summer. Those sites are tested less frequently, about once a month, in off-peak season.
GRDA believes the E. coli is limited to the state park area, but they took some water quality samples from nearby Horse Creek for testing as well.
"E. coli can actually be caused in nature, maybe a flock of birds or something like that, or from another source like a leaking septic system or something," Alberty said.
In addition to the specific GPS coordinates for testing sites, GRDA has permanent pieces of equipment installed in Grand Lake waters.
Those water quality profilers are located above and below the dams. They basically can give real time information back to the lab, but those show data like water temperature and oxygen levels.
Samples at Grand Lake State Park in Bernice and at nearby Horse Creek will be tested every day.
Each time E. coli is discovered, it will extend the time the beach will remain closed an additional 48 hours.