Erosion, the displacement of soil by wind and water action, is perhaps the most common problem that property owners face. It is also a major source of declining water quality.
The buffer zone blocks the erosion process by protecting the land from the water and the water from the land.
Upland erosion occurs when water runs over land forming channels or gullies. Sediment is able to travel easier through the channels and into the lake. Upland erosion becomes even more of a problem when upland trees, shrubs, and undergrowth are removed or soil is compacted. Under natural circumstances, vegetation absorbs and stores water,slows the flow, and allows water to infiltrate the soil.
Erosion directly affects the lake ecosystem. Sedimentation clouds the water, making it difficult for plants to photosynthesize and fish to feed and, consequently, affecting others in the food web. Nutrients and other pollutants carried in the runoff degrade water quality.
Causes of Upland Erosion include:
- Removal of vegetation that buffers the water from the land.
- Concentrated runoff.
- Trampling or compacting soil.
- Improper placement or excessive amounts of gutters, driveways, paths, and impervious surfaces (roads, roofs, parking lots, driveways) that change and increase runoff patterns across the land.
Runoff from the road and parking area of the Maple Lake public access in Marcell, Minnesota had created a gully near the shoreline, carrying unwanted sediment into the lake.
To remedy this problem, a soil berm was created along the parking lot edge closest to the lake to redirect the runoff into a vegetated area. The berm was then planted with trees, shrubs, flowers and grasses.
For an example of correcting upland erosion from a drain culvert, see the Gervais Lake project site.