When the weather turns hot — by Anchorage standards, 70 degrees or more — thoughts turn to swimming.
Alaska's biggest city is dotted with lakes. But where can you swim in Anchorage? And, more importantly, where should you swim?
According to the city: Goose Lake and Jewel Lake. They are the only two lakes in Anchorage that are officially sanctioned for swimming by the municipality.
Both have designated swimming areas, where children and adults can splash within the buoys under the watchful eyes of lifeguards. On a hot, sunny day, hundreds of people can crowd beaches there.
There's no city lifeguard at Mirror Lake, in Eagle River, but the lake is also used for swimming, said Mike O'Brien, a superintendent for aquatics with the city
Plenty of people also use other lakes for unofficial swimming spots, from forest-rimmed "Beer Can Lake," officially known as Little Campbell Lake, near Kincaid Park, to Beach Lake in Eagle River.
"I see people swimming at Taku Lake, DeLong Lake," O'Brien said. "I see people hop in Little Campbell Lake."
Some of those lakes have docks, but no other infrastructure. It's basically swim at your own risk, O'Brien said.
Just how clean are Anchorage's lakes?
Pretty clean, according to city water specialists.
In the mid-2000s, the municipality tested Jewel Lake and Goose Lake for fecal coliform bacteria monthly, from June to August, said Jeffrey Urbanus, a hydrologist with the city. The bacteria indicate contamination by human or animal feces. Resident geese are often the culprits for a high reading.
The water quality was very good, said Jeffrey Urbanus, a hydrologist with the city.
The city stopped testing around 2005, said Urbanus.
"And that's largely because we just didn't see an issue there that like needed to be addressed," he said.
"We're doing well compared to other cities," said Kristi Bischofberger, the city's watershed manager. "But we are a city."
Alaska doesn't have as much industrial activity — or industrial runoff — to contend with as other cities, she said.
"That makes a difference."
The city's Parks and Recreation Department has been testing water for contamination in the same way they do swimming pools, said O'Brien. The most recent reading, from May 2018, didn't show anything of concern.
The city also hasn't tested the other lakes that people informally swim in, but there's no reason to believe they are unclean, Urbanus said.
Lake swimmers' biggest complaint tends to be swimmer's itch, a harmless but annoying rash caused by an invisible parasite found in lake water.
Swimmer's itch is not related to water quality, but comes from a parasite transmitted by waterfowl and snails, said Urbanus.
"During warmer weather the chances of encountering the parasite is greater. The parasite does not survive in humans but can cause a localized skin reaction."
There's isn't a test for gauging levels of the parasite in water, he said. Scientists know they tend to gather in warmer, shallower water.
Lakes are especially prone to develop the parasite that causes swimmer's itch in the later months of summer.
It's kind of gross to think about, but it's really not that serious, Urbanus said.
O'Brien said to his knowledge the city has received zero complaints about swimmer's itch so far this season — though hot weather and heavy lake use is just ramping up this week.
Swimmers can reduce the risk of getting the itch by toweling off after going in the water and swimming in colder water, away from shore.
Everybody has a favorite lake, said Urbanus. He's a fan of Mirror Lake himself.
But why people in Anchorage prefer some lakes and scorn others may be down to preference and perception rather than pollution, Urbanus said. People tend to like "cold, clear water with sand on shore and not mud, or places that are weedy and mucky," Urbanus said.
Urbanus did think of one Anchorage lake he'd avoid: Cuddy Pond, by the Anchorage Library, home to hundreds of waterfowl.
"That may be one place I wouldn't swim," he said.