Swiftly running snowmelt made Hinkson Creek so cloudy on Thursday that the creek bottom was invisible to Randy Crawford as he made his group’s weekly check on the stream.
Crawford, chief of water quality monitoring for the state Department of Natural Resources, was surveying the creek near Stephens Lake Park to look for changes such as odd colors or odors.
On an opposite bank, silt fences could be seen downstream from a construction site — barriers designed to help keep out sediment, which is detrimental to small aquatic organisms such as mayflies, crayfish, snails and small fish.
On Thursday afternoon, the U.S. Environmental Protection Agency decided to keep an 11-mile stretch of Hinkson Creek that goes through Columbia classified as impaired — a designation that holds the promise of additional research to better determine what’s polluting the stream in order to clean it up.
Once the pollutants have been identified, the state will determine a Total Maximum Daily Load.
The load includes five points: the location of the polluted waterbody, the specific pollutants, sources of the pollutants, a calculation of the pollutant load the water can absorb without becoming impaired, and a plan to reduce the pollutant load and restore the waterbody to meet the standards for its designated use.
In its decision, the EPA noted a biological assessment that found mayflies, stoneflies and caddisflies “exhibited a sharp drop in the urbanized portion of Hinkson Creek.” Stoneflies were present in upstream samples in spring 2002, the agency said, but were absent at stations within Columbia.
The EPA ruled the creek is impaired from “unknown” pollutants, setting the stage for the state to develop a plan to restore the stream for its designated uses, including protection of aquatic life, livestock and wildlife watering and boating.
Ken Midkiff, director of the Sierra Club’s Clean Water Campaign, said he hopes the decision will focus attention on cleaning the creek. “If we know the stream is impaired, it should be listed as impaired,” he said. “To the EPA’s credit, political pressure — and I’m sure there was a lot of it — didn’t sway them. They need to see hard, sound science.”
David Shorr, former director of the Missouri Department of Natural Resources, said he would love to see Hinkson Creek listed for the right reasons, but the fact that Hinkson’s pollutants are unknown presents a problem.
He said the list targets a specific pollutant so the community can target that specific pollutant.
“They put our local governments and planning process in a negative position, and that means money and time, I don’t care how anyone talks about it,” Shorr said.
Shorr said the TMDL process is a “community process.”
“If we have a specific pollutant, then the people in that watershed can sit down and address that specific pollutant, and that was the community process that was envisioned,” Shorr said.
During the decisive public comment period, the EPA received 114 comment letters, 41 of which were about Hinkson Creek.
Pat Costello, the EPA’s water quality standards coordinator for Missouri, said he thought this was because the creek is visible through the entire city.
“The concerns about a listing were more based on the impact of development. There’s always concern because of the cost factors that may be associated,” Costello said.
He also said there was a common concern as to how to do a TMDL if the pollutant is unknown.
“A lot of people may agree Hinkson is impaired,” Crawford said, “but finding the source of the problem is difficult, and everybody can’t point their fingers at everyone else.”
Urbanization may contribute to the impairment of the stream, Crawford said, and that’s what part of the research on the creek is designed to answer.