Altered streamside vegetation negatively impacts instream and streamside habitat and destabilizes stream banks. It involves the removal or modification of a waterway’s naturally vegetated banks. Common causes of this type of impairment include the removal of trees from stream banks and/or the mowing of stream banks. In agricultural areas, destabilization can result from animals grazing on and trampling streamside vegetation.
- Healthy stream bank vegetation has many benefits. It provides:
- A buffer zone that prevents pollutants from urban or agricultural stormwater from running off into a waterbody.
- Roots that hold banks in place, preventing erosion and siltation.
- Flood mitigation.
- Habitat for fish and other aquatic life.
- Canopy that shades the stream or river. This shading maintains naturally cool water temperatures critical to temperature sensitive species. Cooler temperatures also prevent excessive algal growth, which in turn prevents the occurrence of harmfully low dissolved oxygen levels.
- A food source for aquatic invertebrates that eat fallen leaves and for fish that eat insects falling from trees.
- Optimal streamside habitat consists of mature vegetation extending 35 to 100 feet from both banks of the stream.