Source of University Lake oil spill in Anchorage remains unknown as cleanup continues

Officials with the state said they still hadn’t identified the source of an oil spill polluting a lake at a popular off-leash dog park in Anchorage as cleanup efforts continued Thursday.

The municipality closed University Lake Park on Wednesday as the size of the sheen on the lake appeared to grow. Water on the southwest side of the lake had an iridescent sheen Thursday morning and the smell of oil lingered in the air.

The spill, first reported on June 21, is still estimated at 20 gallons, despite the size of the sheen growing Wednesday, said Kelly Rawalt, a public information officer with state Department of Environmental Conservation.

“They’re still trying to discern if actual oil is entering the lake or it’s just from surrounding sediment, and if so, it’s probably not very much, if that’s the case,” Rawalt said.

It’s challenging to tell exactly how much oil was spilled because the source is unknown, Rawalt said, but the estimate is calculated by looking at the size and thickness of the sheen. Twenty gallons is a high estimate, she said.

The oil made its way to the area through a device in a city drainage system that separates oil from runoff water before the water is discharged into the lake. The device was overflowing because of the frequent rain in recent weeks and malfunctioned — expelling the oil into the lake instead of taking it away, she said.

The municipality is monitoring the device for further problems, Rawalt said.

The DEC is working with the municipality and the Environmental Protection Agency to track down the source of the oil. They are backtracking through the drainage system and testing for oil at various points to determine where it came from, Rawalt said.

Cleanup efforts began last week when a barrier was placed around the contaminated water to help contain and absorb oil. Workers placed additional barriers Wednesday as the sheen grew in size.

On Thursday morning, workers vacuumed the top of the water to pull oil off the lake. A skimmer device was also placed in the lake to help filter out oil.

Officials from the U.S. Fish and Wildlife Service and Alaska Department of Fish and Game are also monitoring the area. There weren’t any birds in the spill zone Thursday morning, said Angela Matz, the Alaska spill response coordinator for the Fish and Wildlife Service. If birds do approach the area, they haze them to deter them from getting closer, she said. A biologist in a kayak on Thursday herded a duck and her ducklings away from the spill zone.

Anyone who sees wildlife they believe may have been affected by oil is asked to call the EPA’s National Response Center at 1-800-424-8802.

There isn’t an estimate for how long cleanup may take, Rawalt said.

There also isn’t a date for when the park will reopen, a spokesman for the municipal parks department said. Caution tape blocked off access to the polluted water, and entryways were blocked off by orange plastic fencing affixed with signs advising people not to enter on Thursday morning.

“We’re all trying to make decisions to make sure that when folks return to the park that they can enjoy it safely and that their dogs can and that wildlife can,” Rawalt said.