Native vegetation, including grasses, shrubs and trees form a network of roots that hold the streambank soils in place. When this vegetation is removed or mowed, turf grass (lawn) replaces these plants. Turf grass has a very shallow root system. Frequent mowing does not allow the deep rooted plants to survive, and thus, the network of roots holding the soils in place is lost. Energy from stream flow can now erode the soils from the bank.

The above schematic illustrates erosion of a mowed streambank around a tree. In the top left photo, the bank is cutting back around the tree. Note how the tree roots are preventing the soils from eroding as rapidly as those in the lawn area. However, without help from any other root systems, soils will eventually erode out from under the tree roots. Note how the soils have disappeared from under the tree roots in the two bottom photos. Eventually those trees will fall over into the water, having no more soil to anchor in.

Click any photo above for a larger view.

What can you do to prevent it?

Allowing deep rooted plants to remain intact along a streambank (the riparian zone) is the best way to protect it from erosion. Planting native vegetation also shades the water and provides habitat. Point sources can protect and repair streambanks at their facilities or fund restoration of eroding streambanks within the watershed.

Where are the sites of erosion in the Kalamazoo River Watershed?

• Surveys of the Kalamazoo River were conducted by boat. View the site.
• Learn about a restoration project in Ross Township.
• Find out about the Clean Michigan Initiative-funded streambank project (main stem and tributaries).

How do you quantify sediment and phosphorus loading from erosion sites?

Link to the road-stream crossing page for quantification forms (can be used at road-stream crossings or along stream banks).