Anchorage

Anchorage's Chester Creek turned orange last week. Should we be worried?

Anchorage resident David Clark was walking along the Chester Creek Trail last week when he saw something that made him pause: bright orange water flowing into the creek that meanders through Midtown Anchorage.

"I was concerned about the fish and waterfowl in the creek," Clark wrote in an email to Alaska Dispatch News. The opaque water was flowing out of a culvert off Eagle Street, behind the Ben Boeke Ice Arena, around 1:30 p.m. on Feb. 24, according to Clark.

He took photos and emailed them to the mayor's office and the Anchorage Waterways Council. Those photos circulated through city departments, generating possibilities about the culprit behind the visually alarming -- but likely harmless -- colored water.

Orange water plumes have been spotted before in Chester Creek. A July 2012 Anchorage Daily News article describes a similar event that sparked calls to the mayor's office and the nonprofit Waterways Council. And in May 2010, Waterways Council volunteers were working near the same Eagle Street culvert when orange water began to pour into the creek, according to executive director Cherie Northon. Images show the same burnt-orange water spilling into an otherwise clear stream.

The color has a few possible causes. Rusty pipes and iron-rich groundwater are a couple of the theories from the Alaska Department of Environmental Conservation, city Watershed Management and the Waterways Council.

"A rusty pipe would be the most likely cause, and we have plenty of that in Anchorage," said city Watershed Manager Kristi Bischofberger.

Water that stagnates in storm drains causes the metal to rust, and urban runoff -- including salts, cleaning agents and dog feces -- can increase pipe corrosion.

ADVERTISEMENT

"Quite literally everything goes into the storm drains in Anchorage," said Mike Solter, DEC Division of Water compliance and enforcement program manager.

A total of 137 storm drains run into Chester Creek, Bischofberger said, connecting the front yards and streets of Anchorage neighborhoods directly to the creek.

While rusty, degrading infrastructure is one possible factor behind the discoloration, naturally occurring iron is another.

Anchorage has iron-rich groundwater, according to Isaac Watkins, an aquatic ecologist and board president of the Waterways Council. When the groundwater hits the air, it turns to iron oxide, giving it the distinct rust-orange color.

Iron bacteria present in the water adds to the coloring, feeding on the element and creating what looks like a muddy orange slime, Watkins said.

Iron oxide is harmless to animals and humans, Isaac said, and so is the iron bacteria.

"If it's flushing through the system, it'll take care of itself," Isaac said. "If there's a consistent problem, then we'll look into maybe what happened in that storm drain."

DEC agreed. Solter wrote that although it's unsightly, "there is no water quality hazard associated with the iron, and the turbidity was so short-lived that there was likely no significant impact on the stream."

What causes the sudden rush of water into the stream? DEC believes that standing water in the storm drain was likely flushed out either by maintenance or a natural thawing of the pipes, which spilled the orange sediments into the creek, Solter said.

Still, it's hard to pinpoint the exact cause without collecting samples while the water is running, Solter said. "I'm reluctant to say 100 percent what it was just because there were so many factors."

DEC went out to the site on Friday. By that point the water was clear again, but water samples from the area came back with elevated iron levels.

City street maintenance crews also went to look for the source last week. "They were trying to see if they could determine where it came from," said Alan Czajkowski, director of the city's Public Works department. "It could be a lot of things, we're just not sure."

Even if the orange water is harmless, the creek is still considered "impaired water" by the DEC, a definition relating to surface water pollution under the Clean Water Act, said Nancy Sonafrank, program manager for water quality standards assessment and restoration at the department.

Chester Creek is polluted with fecal coliform bacteria. University Lake and Westchester Lagoon are in the same boat, according to the DEC.

Dog feces are the likely culprit -- the DEC, city watershed and Waterways Council all agree. A restoration plan for Chester Creek was created in 2005 and DEC is still working on restoring the water.

Bischofberger said that despite the DEC's classification, overall, Chester Creek is in "pretty good" condition, with resident fish and invertebrate populations. Cleaning up dog waste is "probably the number one thing people can do" to help clean up the water, she said.

Meanwhile, city watershed management will look at the entire drainage system this summer to look for potential sources of the orange water, Bischofberger said.

Laurel Andrews

Laurel Andrews was a reporter for the Anchorage Daily News, Alaska Dispatch News and Alaska Dispatch. She left the ADN in October 2018.

ADVERTISEMENT