Riparian zones, or vegetated areas adjacent to streams and rivers, serve many functions.  Their extensive root systems hold the stream banks in place.  Removing them can induce accelerated stream bank erosion.  Buffer zones also slow down runoff from sites and can filter out contaminants carried in runoff.
	Vegetation along stream banks provide shade – which is essential for the health of the aquatic communities.  Large root wads can provide habitat for fish.
	Grasses do not have sufficient root depth to hold soil in place.  To be functional, the riparian corridor should contain plants with woody stems and trunks.