College of Saint Benedict and St. John’s University student Sarah McLarnan was awarded a Greater Research Opportunities Undergraduate Fellowship with a grant from the U.S. Environmental Protection Agency up to $50,000 to study the impairment of Plum Creek Watershed. McLarnan is an environmental studies and biology major. Dr. Joe Storlien, Environmental Studies Department, CSB & SJU, is her advisor.

 

In 2012, a study conducted by the Minnesota Pollution Control Agency (MPCA) found Plum Creek Watershed in Lyndon Township in Stearns County to be impaired by E. coli, a bacterium found in the intestine of human and warm blooded animals that becomes a contaminant when found in the food or water supply. 

 

At that time, poultry and cattle manure spread on the surface of watershed fields were identified by the MPCA as potential sources of the impairment. 

 

Plum Creek Watershed’s “impaired reach” is from Warner Lake to the Mississippi River northwest of Clearwater. “Impaired for aquatic recreational use” means people swimming in its waters are at risk to exposure for specific disease-producing organisms. 

 

Warner Lake is monitored by the Stearns County Parks Dept., which has determined it is not impaired.

 

Because state and county funds weren’t available to continue monitoring the creek, in 2013 the Lyndon Township board of supervisors authorized limited funds for a feasibility study.

 

At that time, 24 Lyndon Township landowners volunteered to become the Plum Creek Neighborhood Network (PCNN), whose mission is to get Plum Creek off the impaired list of streams. The MPCA requires three to four years of levels below contamination level for a creek to be taken off the list.

 

Reed Larson, North Watershed Section Manager, MPCA and Dennis Fuchs, Stearns County Soil and Water Conservation District administrator, committed their technical resources and staff experts to assist in the project.

 

The MN Dept. of Transportation, Stearns County Environmental Services, Stearns County Public Works, Stearns County Parks Department and Dr. Charles Nelson, retired hydrologist from St. Cloud State University and PCNN member, have also given their assistance and cooperation.

 

“Because we were concerned there were other bacteria sources than livestock manure contributing to the problem, we requested additional assistance from Dr. Michael Sadowsky, director of the Bio-Technology Institute at the University of Minnesota,” said Jerry Finch, watershed specialist and Lyndon Township supervisor. 

 

Dr. Sadowsky believes persistent strains of E. coli are likely naturalized to the sites, capable of growing in sediments and surviving through repeated freeze-thaw cycles. 

 

He states ditch sediments are potential sources of E. coli in the environment, which confounds the use of this bacterium as an indicator of fecal contamination, and has implications for future water quality monitoring and determinations. 

 

Dr. Sadowsky also suggested DNA analysis to determine the origin of the E. coli. The results were negative for livestock and human contamination.

 

McLarnan’s research project includes performing more in-depth sampling than previously done, and looking at the streambed sediments and other stream conditions. She and her team are exploring the possibility that the periodic E. coli impairment is caused by the streambed sediment being churned up when the water is moving more quickly.

 

This fall McLarnan will finish sampling and begin analyzing the data. Where the impairment is determined to be coming from will decide which direction her project will take next.

 

In an August press release from CSB, McLarnan said the main question is whether the contamination is coming from human or natural sources, and that the answer to that could mean two very different courses of action. 

 

She stated if the contamination is due to human action, the question is can it be fixed and what resources would be needed to do so? On the other hand, if the contamination is due to natural sources, the question is it really a problem that needs to be fixed, and whether E. coli is the best indicator of bacterial impairment.