Buffers strips are areas of permanent vegetation between rural lands and bodies of water such as agricultural drains, creeks, rivers, ponds and wetlands. Buffers can have trees, shrubs, grasses or wildflowers, in any combination. As their name suggests, they protect waterbodies from the impacts of neighbouring land uses.
Reduced water pollution
Surface runoff from agricultural fields and rural properties can carry sediment, nutrients, pesticides, bacteria and pathogens. Buffer strip vegetation stops pollutants from reaching the adjacent waterbody by taking up nutrients, trapping and filtering sediment as the runoff is slowed down by the plants, and increasing the infiltration of runoff through plant root channels.
Roots from grasses, shrubs and trees protect vulnerable soils and strengthen and stabilize stream banks.
Overhanging vegetation shades the water, helping to cool and regulate water temperature. Plant litter and organisms are an important food source for aquatic and terrestrial wildlife. Riparian buffers also provide shelter and corridors for wildlife movement.
Planning a buffer
Work with someone familiar with riparian restoration who will consider your land, time and money constraints to create an effective buffer. In general, the wider the buffer strip, the more effective it is. Factors to consider when planning a buffer include:
• 5 m for bank stabilization
• 10-30 m for sediment removal
• >10 m for wildlife habitat
• The steeper the slope, the greater the potential for runoff and erosion. A steeper slope requires a wider buffer to slow runoff.
• Sandy soil allows more infiltration compared to soils with high clay content. Poorly drained soils require a wider buffer.
• The vegetation must be able to withstand flooding by water and sediment.
• Grasses are better adapted for filtering and absorbing nutrients; trees help stabilize the bank.
• Stiff stemmed grasses planted at the field edge of the buffer help slow runoff and reduce concentrated flow in the non-growing season.
• The effectiveness of the buffer may be limited to the vegetation growing season.
• Buffer health may be affected by pesticide in runoff.
• Newly planted trees and shrubs may need watering during the first growing season.
• Weed control is critical until the planted vegetation becomes established.
• Inspect the buffer periodically to ensure that concentrated flows have not developed and the vegetative cover is maintaining its effectiveness.
• Fertilizers, pesticides and animal wastes should not be applied to the buffer.
• Limit grazing by livestock in the buffer strip.
For more information
To learn more about buffer benefits, design, and maintenance, check out the Buffer Strip BMP publication.