River won't run clear

Locations and severity of

pollution

Second in a series

By FRITZ BUSCH

Journal Staff Writer

NEW ULM -- The Minnesota River Basin was once a prairie and wetland landscape that for the most part, supported hundreds of flocks of birds and bison herds.

When European Americans settled the area, they established cities and towns, plowed the prairie, and drained the wetlands. River water quality was seriously degraded due to significant changes in land use during the past 150 years.

The river basin is now dominated by a vast agricultural landscape. Inhabited by 700,000 people, the area contributes billions of dollars to the Minnesota economy. At the mouth of the river -- where it enters the Mississippi River -- lies the Twin Cities.

The agriculturally dominated Minnesota River basin covers 10 million acres and drains 12 major watersheds. Several years ago, the river was listed as one of the 20 rivers in America most threatened by pollution.

River water quality is more severely impacted in the spring and fall by bacteria and viruses that cause disease, particularly in children.

Suspended soil particles (sediment) carry phosphorus into the river, making it look muddy and cloudy, restricting the ability of fish to spawn and limiting biological diversity. Regardless, the river will never be a crystal clear running stream.

Phosphorus stimulates the growth of algae that decompose and reduce oxygen levels which can kill fish and other aquatic organisms.

Nitrate-nitrogen in drinking water can cause infants to become sick.

Regional effects are more common in summer when the river is low. There is growing concern that the hypoxic zone (an area of very low dissolved oxygen levels in water) in the Gulf of Mexico is caused by nitrate nitrogen from the Upper Mississippi basin, including the Minnesota River Basin. Low oxygen levels in fresh or sea water cause fish and other organisms to die.

Water quality monitoring samples taken in the Minnesota River at various locations from 1968 to 1994 indicated a wide variance of standards violations.

Dave Mulla, professor at the University of Minnesota Department of Soil, Water and Climate, said that although the statistics are not the most recent, he thinks they are representative of the Minnesota River watershed today.

Among the more alarming data was the extreme phosphorus level in the Redwood, Cottonwood and Minnesota river watersheds. The extreme area stretched from west of Marshall to the Twin Cities, nearly reaching Olivia to the north and just north of Windom to the south.

The highest phosphorus level was measured near Fort Snelling where 70 percent of the water quality monitoring samples violated federal standards. Sixty-three percent of the samples near St. Peter and 60 percent near Courtland were in violation. Phosphorus violations were as low as 31 percent near Milan.

Fecal coliform violations reached 52 percent of samples taken near Courtland and 48 percent near St. Peter. Violations were frequently reported on the river between Morton and Fort Snelling.

Now, the good news.

Biological phosphorus removal procedures at the Blue Lake and Seneca waste water treatment plants reduced phosphorus loads from waste water effluent by 60 to 70 percent, according to the Minnesota River Basin Water Quality Overview, produced by the Soils Division of the University of Minnesota Agriculture Department.

The most important river pollution sources, according to the University of Minnesota study:

* Sediment and nutrients from agricultural cropland

* Phosphorus and bacteria from municipal waste water treatment plants

* Bacteria and other pathogens from septic systems

* Sediment from stream bank erosion

* Nutrients and bacteria from animal manure runoff

Some of the Best Management Practices effective at protecting water quality include:

* Conservation tillage on erodible, well-drained lands

* Sediment basins and animal waste management facilities

* Grassed waterways, filter strips and riparian buffer strips

* Soil testing prior to fertilizer or manure applications

* Following University of Minnesota guidelines for applications of fertilizer or manure

For more information, visit: http://www.soils.agri.umn.edu/research/mn-river/doc.watqual.html

Thursday's river feature will center on some of the focus group findings on addressing non-point source agricultural pollution in the Minnesota River Watershed and how some conservation groups view the latest version of the Farm Bill.