Streambank vegetation is extremely important for the physical, chemical, and biological integrity of the stream ecosystem. Clearing stream banks of trees, shrubs, and other vegetation can leave the waterway vulnerable to pollution and damage from erosion and runoff. Erosion is a natural process that deepens the streambed and causes it to meander over time. However, excess erosion can cause stream banks to collapse and the stream channel to be clogged with sediment, destroying habitat for important stream taxa such as fish and benthic macroinvertebrates. Human activities such as the clearing of natural vegetation by landowners, urbanization or development, the construction of impervious surfaces (roads, buildings, drainage ditches, etc.), and agricultural practices (grazing, plowing) can exacerbate and accelerate erosion problems within a watershed. Streambank vegetation is also important for controlling runoff, the draining of water from the rest of the watershed into the stream. This water carries with it pollutants and excess nutrients from the landscape, such as nitrogen and phosphorus from fertilizers that can cause eutrophication, salts and chemicals from roads, and sediment from construction sites.

Changes to the rate of erosion and runoff can cause cascading effects throughout a stream ecosystem, degrading and reducing suitable habitat for aquatic organisms and reducing water quality. Streams are complex and sensitive ecosystems that respond to a wide variety of factors such as habitat structure, flow regime, changing energy sources, and biotic factors, and changes to one aspect of the ecosystem can influence many other variables.