Pomme de Terre Watershed Project - Part One: Watersheds 101
The following is the first in a series of articles about the Pomme de Terre Watershed and the TMDL studies that are now underway studying the pollution problem in the watershed.
By Shaun McNally
As most of us who live in the area know, the Pomme de Terre is a local river. But the Pomme de Terre is also a watershed. What exactly is a watershed and how big is it? A watershed is essentially an enormous precipitation collecting, storing and routing device. It's an area of land that drains water to a common point... the Pomme de Terre River.
Watershed boundaries are set by nature, not by the legislature. Wherever the water runs determines the watershed an area is in. For example, Stevens County is part of three watersheds. The west-northwest area of the county is in the Bois de Sioux Watershed. The very eastern portion of the county is in the Chippewa Watershed. And, the center and most of the southern part of the county is in the Pomme de Terre Watershed.
The Pomme de Terre begins its journey from Stalker Lake in Otter Tail County just south of Underwood. In its upper course, the river flows through a morainic region of numerous lakes, with well drained silty and loamy soils, its course characterized by meadow, woody hills and marshy stretches near areas where the river passes through lakes.
Downstream from Morris, the river flows on till plain composed of poorly drained clay and loam soils. Slight to high water and wind erosion potential exist in this section of the basin.
South of Morris, flowing through Stevens and Swift Counties, the river is bordered by eroding, muddy banks and becomes increasingly murkier. The river discharges into the Minnesota River at Marsh Lake, just southwest of Appleton.
While the Pomme de Terre River itself is 106 miles long, the watershed itself covers 866 square miles. In the watershed are 750 miles of streams, creeks and ditches, 43,000 acres of open water, and 78,000 acres of wetlands. The watershed includes parts of six counties; Stevens, Swift, Otter Tail, Grant, Douglas and Big Stone. Towns in the watershed include Underwood, Dalton, Ashby, Barrett, Donnelly, Morris, Chokio, Alberta and Appleton.
The watershed is divided into six sub-watersheds. The upper sub-watershed is the headwaters region south of Underwood. The Pelican Creek sub-watershed is located around the Ashby area. The middle sub-watershed is a narrow band starting just north of Barrett and follows Highway 59 down to Morris. The lower sub-watershed follows Highway 59 south of Morris down to Appleton. The Muddy Creek sub-watershed includes Chokio and Alberta, and the Dry Wood Creek sub-watershed includes the areas around Artichoke Lake and east.
The Pomme de Terre watershed is one of 12 watersheds in the Minnesota River Basin. Water from the Pomme de Terre flows into the Minnesota, which flows into the Mississippi, which flows into the Gulf of Mexico. So in theory, what goes into the Pomme de Terre can have an effect on the Gulf.
For decades, people living on the river have been noticing a decline in water quality. The river becomes increasingly murky during high flow periods and green with algae during low flow periods. This phenomenon seems to be a more recent one, as Eric Sevareid, canoeing up the Minnesota River during the summer of 1930 wrote; "We paddled on, nagging at the heat and flies, until we came to the Pomme de Terre, or Potato River, clear as crystal, flowing into the muddy Minnesota."
In the early 80s a group consisting of six SWCD supervisors and six county commissioners formed the Pomme de Terre River Association. This group formed a Joint Powers Board. This gave the Association legitimate authority to apply for grants and seek money for projects to clean up the watershed.
Water monitoring of the river in the 80s and early 90s tested water samples for Fecal Coliform bacteria. Of the 74 samples taken, 23 showed Fecal Coliform concentrations higher than allowable limits set forth by the EPA. Results of this study put the stretch of the Pomme de Terre River, from Muddy Creek just south of Morris to Marsh Lake just southwest of Appleton, on the EPA's list of impaired waters for Fecal Coliform.
As more water quality data began being collected, another problem came to light. Testing showed the same stretch of river from Muddy Creek down to Marsh Lake to be under impairment for turbidity. Turbidity is a measure of the amount of particles suspended in the water, such as sediments and algae. Higher turbidity levels reduce the amount of sunlight that can penetrate the water and can affect species of aquatic life that survive in the water. In 2002 the same stretch of river was put on the EPA's impaired waters list, but this time for excessive turbidity.
So now we've got a section of the River that is on the EPA's list for two different pollutants. What can we do about it? The Pomme de Terre River Association began to apply for grant money to study and begin to do something about the problem.
The next article will discuss the different sources of pollution in the Pomme de Terre watershed.
There will be public meetings later on this summer about the upcoming turbidity project. If you are interested in being part of a stakeholder group, please contact Shaun at 320-589-4886 ext.109. We are looking for a diverse interest group for our stakeholders including agricultural, municipal, county, recreational and environmental interests.
The Pomme de Terre River Association maintains a website: www.pdtriver.org
Shaun McNally is the Pomme de Terre watershed project coordinator located in the Stevens SWCD office in Morris.