The swimming restriction has been lifted for Don Carter State Park.
Bacteria levels have returned to safe levels at the state park about 15 minutes from downtown Gainesville, said Georgia State Parks spokeswoman Kim Hatcher on Thursday. The state performed another water quality test at the park on Tuesday, but the results take a couple of days.
The state closed swimming and wading at the park for several days because of unsafe levels of E. coli bacteria found in the area. Don Carter appears to be unique, as other officials said Thursday that there have been no other hot spots for bacteria this spring.
It’s not clear what caused the concentration of bacteria at Don Carter, but bacteria levels tend to increase after heavy rain as runoff enters the lake and its tributaries.
“Typically we see very low levels of E. coli throughout the (Chattahoochee) river system, but after heavy rains where storm water washes contaminants … into the river, we do see E. coli spikes,” said Jason Ulseth, riverkeeper for the Chattahoochee Riverkeeper.
Ulseth is the environmental conservation group’s spokesman and lead advocate.
The state will perform weekly tests at the park for the rest of May, according to Hatcher. She said on Wednesday that the concentration was unusual for the state park, which had never seen swimming restrictions because of bacteria before now.
There have been no other reports of unsafe concentrations of any kind of bacteria at designated swimming areas in Lake Lanier, according to Nick Baggett, natural resource director for the Army Corps of Engineers in Buford.
“Usually we start a few weeks before now during what we consider the rec season, when people start using the beaches, but we’ve not had any high levels to worry about as far as testing we’ve done at designated swim areas,” Baggett said on Thursday.
The Army Corps’ most recent test was performed Tuesday. The state also regularly tests its swimming areas at Don Carter State Park leading up to Memorial Day weekend — the unofficial start of Lake Lanier’s busy season.
At Lake Lanier Olympic Park, manager Morgan House said there have been no unsafe levels of bacteria found nearby, but he noted he’s requested testing after the news at Don Carter State Park.
Some areas of Lake Lanier are more prone to high concentrations of bacteria.
“We do see elevated E. coli levels on heavily urbanized tributaries like Flat Creek and Balus Creek,” Ulseth said, adding that “creeks that have a more rural watershed” also generally have less bacteria.
While runoff into streams and drainages can carry contaminants into Lake Lanier, one of the biggest causes of bacteria spikes is Canada geese.
“They will come to a beach area, mill around, defecate and cause these high levels of bacteria,” Baggett said.
The geese were introduced to Lake Lanier with the expectation that they would migrate, he said, but instead they’ve become resident geese — making them a constant problem as they move around the lake.
Whether the cause is geese or rain, Ulseth recommended people avoid swimming or wading if they see cloudy, muddy water.
“Typically once the water starts to clear … and the cloudiness of the water starts to clear up, you see the E. coli levels decline at the same time,” he said.
Ulseth recommended that people with open cuts or sores cover their wounds before entering Lake Lanier or avoid swimming at all.