WASILLA — Cottonwood Creek is Wasilla’s urban waterway, bisecting the Valley’s largest city.
It burbles past the Alaska Club, the police station, Fairview Loop Road’s horse farms and subdivisions.
Coho and sockeye salmon as well as rainbow trout swim in the creek. People canoe on it. Moose feed in the shallows just off the highway. Near the bustling Fred Meyer, waterfowl frequent an ice-free spot known as the duck pond.
But bacteria — fecal coliform bacteria — lurk in those waters, at levels exceeding state standards. The bacteria come not just from human waste but from horses and dogs too.
The Alaska Department of Environmental Conservation knows that because they launched an investigation into the source of the creek’s fecal coliform.
They DNA tested it.
Laura Eldred, an environmental program specialist in the agency’s water division, said the state shipped Cottonwood Creek fecal coliform samples to an Oregon State University lab.
“They found a little bit of everything: dogs, horses, waterfowl but also humans,” Eldred said. “That’s where the real problem is.”
Humans produce waste leaking from old, failing septic systems or even honey buckets — at least one of those was found along the creek — but also bring in the dogs and horses that produce plenty of waste of their own.
The state agency says Cottonwood Creek violates standards for fecal coliform bacteria and the agency is now developing a recovery plan. The plan, technically known as a TMDL or Total Maximum Daily Load, is a pollution budget that determines how much fecal coliform bacteria can reach the creek and still stay within state limits.
A public comment period on the draft TMDL ends Jan. 30.
The bacteria occur naturally in digestive tracts of all warm-blooded animals, and while they don’t necessarily make people sick, they indicate potential problems with sewage contamination that could.
The bacteria levels make Wasilla’s waterway the first in the Matanuska-Susitna Borough to be “listed” by the state for exceeding bacteria levels, though Wasilla’s Lake Lucille and Big Lake exceed other standards for dissolved oxygen and petroleum hydrocarbons, respectively. And an open dump site on the Matanuska River also triggered an impaired listing on a section of that waterway.
Most Anchorage streams are already listed for bacteria, Eldred said.
Fecal bacteria wasn’t an issue on Cottonwood Creek 20 years ago.
“Most urban waters can handle so much development and pollution and runoff before it gets to a point of impairment,” she said.
The creek starts in a series of wetland springs up Engstrom Road, passes through 10 different lakes, crosses the busy Palmer-Wasilla Highway and then hits the Parks. The section that’s the focus of the state recovery plan starts there and flows seven miles to just before the creek’s estuary at the Palmer Hayflats.
The state did a scan of all the properties listed on Matanuska-Susitna Borough records near the creek. They came up with 193 within 200 feet, 163 from 200 to 499 feet of the creek and 309 within 500 to 1,000 feet.
Not all those properties necessarily have septic systems — but they likely will if they’re developed, Eldred said.
The state didn’t pinpoint the cause of Cottonwood Creek’s bacteria as flowing from any one particular property or farm. Rather, the bacteria probably come from storm runoff that’s picking up bacteria from many sources and washing it into the water. Maybe there’s a septic leach field too close to the water or an old one that’s not up to snuff, or garbage stored nearby with, say, diapers in it.
The Clean Water Act requires states to develop a pollution control plan, the TMDL, for any impaired water body. The plans are submitted to the U.S. Environmental Protection Agency for review and approval. The states put them into practice, with partners, though the plans aren’t under state regulation in Alaska, Eldred said.
Either way, as water quality advocates see it, the creek’s draft pollution control plan makes for a great public education opportunity.
There are several ways landowners can help remedy the high levels of fecal coliform flowing into Cottonwood Creek, according to a fact sheet DEC is publicizing with the draft report.
Landowners who have livestock can sign up for a federal program to improve water quality in runoff that’s administered by the Natural Resources Conservation Service in Wasilla.
Creekside homeowners can also get financial help with stream bank restoration such as planting willows or other vegetative buffers via a federal program administered by U.S. Fish and Wildlife Service in Anchorage.
Then there’s the “septic smart” program — people living in the same subdivision can pool together to get reduced rates from septic waste hauling companies.
At least two dozen people have signed up in subdivisions along lower Cottonwood Creek either through prior cooperatives or through the new outreach initiative, according to Catherine Inman, whose company was contracted by the nonprofit Mat-Su Resource Conservation & Development to coordinate the program.
The program helps play matchmaker between neighbors who might not otherwise “knock on some person’s door and say, ‘Hey, when are you pumping?’ ” Inman said.
Valley residents sometimes take their urban creek for granted but Cottonwood has played host to thousands of local school students on field trips, still has fish runs caught by anglers on the Hayflats, and played host to a Teeland Middle School Program restoration project. Two hundred middle schoolers repaired 80 feet of creekside by replanting willow to cover up a four-wheeler track across spawning grounds, Inman said.