Hinkson Creek is crippled by a barrage of pollutants, including fertilizers, insecticides, petroleum by-products, oil, salt and E. coli bacteria, a new study by the Missouri Department of Natural Resources shows.
DNR water quality data on Hinkson Creek released Monday evaluate nine months’ worth of sampling from a 1½ -mile portion of the stream spanning north of the Columbia landfill to Broadway just north of downtown. The data are significant because they are the first to detail specific pollutants in the stream, which the EPA has included in its list of impaired waters since 1998.
The results show that Hinkson’s contamination problems start when the stream reaches Columbia city limits.
That means scientific data now support what many Columbia residents already suspected — Hinkson Creek is suffering because it runs right through a growing urban area.
Most of the results are based on water samples gathered from a collection of storm-water drains that empty into Hinkson from the Broadway Marketplace shopping plaza and the Missouri Department of Transportation maintenance center on Conley Road, as well as the Columbia Country Club and Interstate 70.
Findings from the study, which detail both water quality and sediment problems, include:
- Forty-three, or 16 percent, of the DNR’s water samples for Hinkson were partially toxic or lethal to aquatic insects after they were exposed to the samples in the DNR lab.
- Water from a Wal-Mart Supercenter parking lot drain contained carbaryl, an insecticide common in lawn products.
- Water drained from I-70 and sediment near I-70 contained a laundry list of pollutants, including petroleum products and plasticizers.
- Runoff from the transportation department parking lot contained petroleum products and waste oil. The lot is a storage site for large petroleum and oil tanks and road-building and maintenance materials.
- Runoff at the transportation department center gathered after a snow melt in February 2003 contained a level of salt nearly 1,000 times higher than normal for Missouri streams.
- Runoff from I-70 and Broadway Marketplace had higher-than-normal levels of salt after the February snowmelt.
- Some sections of the stream contained high levels of E. coli. The sections include the I-70 drainage site, the section of the creek that runs under Broadway near Old Highway 63 and two sites outside the urbanized portion of the stream.
- Eight-foot gashes in the creek banks behind Broadway Marketplace and the transportation department lot indicated that increased storm-water runoff has torn massive amounts of sediment from the shores into the creek. That sediment fills the creek bed and makes it difficult for fish to thrive.
- Construction equipment drove through the creek bed and tore into its banks.
Randy Crawford, a supervisor in the DNR’s water-quality monitoring section who’s heading up the Hinkson study, said the DNR had expected to find pollutants such as petroleum and fertilizers, which are common in urban streams and often found in runoff from parking lots filled with cars.
He added that some of the salt found in the study was probably flushed into the creek after it was dumped on roads to melt ice in winter.
But the high salt level at the transportation department lot was another story — Crawford said it was probably because the department was improperly storing road-clearing salt at the site and it seeped into the creek.
Crawford said Hinkson’s E. coli levels also took DNR scientists by surprise.
He said E. coli, which is typically found in feces, is not by itself a threat to Hinkson’s aquatic life and could be there because of animal droppings or leaks in the city’s sewer system, which abuts the creek in several places. But Crawford said E. coli’s presence in the water might be dangerous because it indicates the likelihood that other harmful bacteria are in the creek, a potential danger to both fish and people.
“There’s something going on in the system,” Crawford said.
He said more tests should be done to figure out whether the E. coli findings were unusually high in 2003-04 or whether those numbers are typical in Hinkson Creek.
Bryan Fawks, regional deputy director of DNR’s Water Protection and Soil Conservation Division, said the study results, which are the first in a series of reports the DNR hopes to release in the next six months, are coming out early so Columbia can work on the problems as soon as possible.
“These are all problems that are not insurmountable, but increased diligence in land disturbance would go a long way,” Fawks said.
To that end, representatives from the DNR on Friday met with representatives from the city, the transportation department and the development community of Columbia, including the owners of Broadway Marketplace.
Fawks said the DNR is going to send a letter to the city in the next few weeks asking it to create a plan to help Hinkson Creek.
The first portion of the study cost the DNR about $50,000. Crawford said the DNR staff next will study the creek from Broadway to Providence Road.
The study of all 14 impaired miles is scheduled to be completed in three years, but it could be several more years before the state and the city are able to develop a comprehensive plan to protect the Hinkson Creek watershed.