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The Pomme de Terre River Watershed and Morris Water

The Western Minnesota landscape (and our groundwater resources) were formed during the last glaciation which ended around 10,000 years ago.

Morris is in the Pomme de Terre River Watershed in the Minnesota River Basin - all of our water flows south to the Minnesota River where it joins with the Mississippi and heads to the Gulf of Mexico.

Pomme de Terre River

  • High levels of nitrates and nitrites. Seventy four percent (74%) of land in this region is used for agricultural purposes.  Pesticides and fertilizers run off farm fields and leading to high nutrients water systems which creates environmental and public health concerns.

  • Limited Buffer Zones. In many areas cropland used to extend right to the edge of the Pomme de Terre River or wetlands.  This minimizes the natural resistance to flooding and the natural filters for sediment, pesticides and nutrients. This also reduces the habitat needed for many wetland species. Without native prairies plants extending their long roots into the soil this also leads to an unstable and rapidly changing river channel which is prone to erosion.   Concern for these issues lead to a Minnesota-wide law was passed in 2015, called the MN Buffer Law, which requires farmers to leave strips of perennial vegetation between fields and wetlands.

  • Connectivity issues.  The dam at the southern end of Pomme de Terre Park eliminates the ability of wetland organisms that live south of the dam to move north - this is particularly impactful to 14 migratory fish species.

  • Low levels of dissolved oxygen, non-point phosphorus pollution and coliform bacteria are also concerns.  In general, the Pomme de Terre River south of Morris faces more problems than the river does north of Morris.

Crystal Lake

There has not been enough data collected to make firm conclusions but data collected suggests that it will not meet water quality standards.  High levels of phosphorus and high total dissolved solids are a few of the suspected issues.

Drinking water

Source: Morris water (for drinking, washing, irrigation) is groundwater. It is pumped up from beneath the ground surface from the Pomme de Terre Aquifer.


Problems: The bedrock in Morris is largely limestone which is made of calcium and magnesium carbonates.  Hard water a term used to describe water that has a lot of carbonates in it. This is why (if you have unsoftened water) white rings form around faucets or hoses and soap doesn’t get as sudsy as it does in water that is less hard.

Usage: The total, daily water usage of the entire City of Morris is 700,000 gallons per day. 

Hard Water

What is hard water?

Hard water has lots of minerals that you can’t see with just your eyes (usually calcium and magnesium) Soft water has less minerals.

If you have hardwater, you may notice white, flakey rings around your sink, shower or hose.  Or that when you travel other places your soap might have more suds than it does here. That’s because the water in Morris is hard water.

Why is Morris water hard?

In Minnesota, a lot of the earth that’s beneath our feet and under our houses is limestone (rock that is made of calcium and magnesium carbonate).  A lot of water exists below the surface of the Earth (in areas called aquifers) and when it is next to limestone some of the minerals from the limestone end up in the water.

Reducing water hardness

While hard water is usually safe to drink, it can be bad for our pipes and faucets. To eliminate some of these problems, we can make water less hard by removing some of the minerals.  To do this, we filter the water go through some salts (like the salt you use on your food) and the minerals in the water stick to the salts and stay with them instead of staying in the water - making the water less hard. 

What happens to Morris water after we use it?

It goes out to the Pomme de Terre River. After softening, some of the salts stay in the water. The wildlife and plants that live in or near the river are very sensitive to changes in their water, including the chloride from the salt.  A lot of people in Morris use water softening systems in their homes and the salty wastewater has been damaging the river ecosystem.  In order to lower the salt levels, Morris put in a new water treatment plant to make the system more efficient and reduce the impacts on wildlife.

What does the water treatment plant do?

The new water treatment plant reduces the hardness of Morris water centrally (bringing hardness values down from 40-45 grains of hardness to 5-7 grains of hardness).  Additionally, the plant uses lime and soda ash to limit the chlorine discharged into the Pomme de Terre.

Sources and More Information

Reports and information from the City of Morris, the Minnesota Pollution Control Agency (MPCA) and other institutions on the health of the Pomme de Terre River Watershed.

"Morris Chloride Study" by the Minnesota Water Quality Association (MWQA)

Biotic Stressor Report by the MPCA 2012

"Hydrogeology of Confined-Drift Aquifers Near the Pomme de Terre and Chippewa River Aquifers, Western MN," USGS 1986

Watershed Report 2013 by the Minnesota Pollution Control Agency

Monitoring and Assessment Report by the Minnesota Pollution Control Agency 2011

"Regional Hydrogeologic Assessment Traverse-Grant Area, West-Central Minnesota," DNR 2008


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News Articles

"Nitrogen in Minnesota Surface Waters," MPCA 2013

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Minnesota Well Owners Association:

Minnesota Rural Water Association:

PDFs of the below information available here:

Morris Water Overview

Morris Water Treatment Plant

"In Morris and other cities, solving a salty problem in municipal water," MPR. Mar 19, 2019.

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