The Grand River Dam Authority reports a high level of E. coli will keep a swim beach at Grand Lake State Park closed for a while longer. The GRDA blames feces from geese for the contamination.
The Army Corps has also closed some beaches at Lake Tenkiller because of E. coli. They aren't sure of the source of the E. coli at Tenkiller, but they've closed swim beaches at Snake Creek, Chicken Creek and Cookson Bend.
The Tulsa Health Department found high levels of E. coli at all three, causing swimming to be closed at the beaches.
"I've been seeing a little more elevated numbers recently, which makes sense with the rain," said Lindsey Walsh with the Tulsa Health Department.
The water quality lab at the Tulsa Health Department does the testing. Walsh, a microbiologist, said the E. coli levels vary a great deal, even from different sides of a beach.
"With the rain slowing down, it should return to normal relatively quickly," she said. "Today's samples for Lake Tenkiller were coming down and it was looking promising."
The decision to close the beaches at Tenkiller was made by the Army Corps of Engineers. Spokesman Ross Adkins said their testing in years past usually didn't find a problem, but a variety of factors can concentrate E. coli.
"The lower water levels mean it's more concentrated and the heat isn't going to help and when the water is lower, it's more stagnant," Adkins said.
The Corps plans to keep the beaches closed until testing indicates the water is safe, and while the E. coli level is high now, they'll get a new set of results this Friday.
"When you get out to the deeper parts of the lake it's more diluted because of the depth of water, so when they close the beach, they're waiting for the natural ebb and flow of the lake to dilute it down to an acceptable level," said Elizabeth Nutt with the Tulsa Health Department.
At both Tenkiller and Grand, the contamination is only an issue at a few spots. The other beaches remain open and the parks and lakes remain available for use.