Transcript: Erosion: Sculpting the Landscape
Hi, my name is Kate, and I work for Friends of the Mississippi River. FMR is an environmental non-profit based in downtown St. Paul with a focus on protecting the health and vitality of the Mississippi River as it flows through the metro area.
This portion of the river is particularly important, as it is also a national park called the Mississippi National River and Recreation Area. Our national park is the river as it flows from Dayton, Minnesota in the northwest to Hastings in the southeast.
FMR has four programs to help protect the river.
We’re at the capitol promoting laws and rules that will protect our Minnesota waters.
We work with local communities organizing around local development and river-related issues.
We work with landowners to help restore their property to native habitat.
And we organize volunteer and educational events for all ages.
In this presentation, we’re going to talk about our local landscape and how erosion has formed many of the features we see today. A landscape are the features of an area of land that we can see, like hills, valleys and mountains.
Here’s a picture of the Grand Canyon. Do you think we have anything like the Grand Canyon in Minnesota?
Or maybe, Niagara Falls? Okay, few things are as stunning as the Grand Canyon or Niagara Falls, but we did have a waterfall as large as Niagara here in the Twin Cities. And now it is…
St. Anthony Falls. The Mississippi River once was a massive river that came rushing through the Twin Cities area at the end of the last ice age. That river, called the great River Warren, carved a large pathway through the metro area. What is left of that waterfall is now St. Anthony Falls and Minnehaha Falls. And….
…you can see what is left of the path of the great River Warren, as it is now the river gorge between Minneapolis and St. Paul. The river gorge looks like a steep, narrow valley, and the Mississippi River flows through it at the very bottom. This valley broadens in St. Paul so that one side is at the high end of the High Bridge and the other side is where the capitol and cathedral are today.
Here we have some of the major rivers in Minnesota highlighted. One of the interesting things about Minnesota is that we don’t have major rivers that flow into Minnesota. All of our water flows out of the state. We can see that the Red River flows into Canada, the St. Louis River flows into Lake Superior, and the St. Croix and Minnesota rivers join the Mississippi River flowing south. For the moment we want to focus on the Mississippi and Minnesota Rivers.
And I have a challenge question for you. Why do you think the two rivers look different in the picture on the next slide?
When you have an idea, please share them with us! You can find us at the FMR Facebook page or our contact information at www.fmr.org.
This might help you with some ideas. Here is a Minnesota map, again, with some of the main rivers highlighted. The different colors on the map indicate the land use in different areas of the state. The northeast has a lot of forests and lakes while the western part of the state has more cultivated farmland.
Our landscape has been formed by erosion, and it continues to be formed by erosion today. Erosion is the movement of soil from one location to another by water or wind.
Erosion itself is not a problem; wind and water have been eroding soil for eons. The problems start to happen when there’s too much erosion, particularly because of human activity.
A couple of problems with excess erosion we can quickly see on the landscape is that when the soil underneath our buildings, sidewalks and roads starts to wear away, those structures begin to collapse. This is where things like sinkholes or cracks in a wall can start to develop.
Soil eroding from farm fields causes large problems in the field, as that important soil for growing crops is now washed into streams and rivers. In addition, soil can start to cause gullies in the fields, like you can see in some of these photos.
Erosion causing water quality problems are not often as visible to us, but extra soil in the water makes it hard for animals to see food to eat.
All of that extra soil in the water can also settle on the bottom of the waterway. When this happens, it covers the things that are on the river bottom, such as fish nests, plants and mussels. When these plants and animals are covered with soil, they can’t survive since they can’t move to remove the soil. For example, mussels filter the water and eat small particles they catch. With more dirt in the water, it’s harder for them to eat since most of the particles they catch are inedible dirt.
So, how could we prevent all of this soil from getting into the water? Really, one thing can solve most of this problem.
Plant roots hold onto the soil and prevent it from washing into the water.
The thing is that not all plants have the same type of roots, and some roots hold onto soil better than others. Plants that we commonly find in our yards have very short root structures that don’t hold the soil well. For example, the grass we often plant on our lawns has short roots that are six inches long, and other common yard and park plants have roots of just two or three feet.
Many plants that are originally from Minnesota, called native plants, have long root structures and are great at keeping soil in place. Native plant root structures can be anywhere from six-feet to 15-feet long. Those long roots are going to hold a lot more soil than our typical lawn grass, and they can help to prevent erosion. The good news is that more and more people are choosing to convert their lawns to native plantings, which also protects our water.
So please join us in preventing erosion by planting native plants and trees either at one of our events or in a green space that you can grow plants.
You can find more information on FMR planting events at our website www.fmr.org and find our events calendar. We look forward to seeing you and have a good day!