- Background
- Project Highlight
- Additional Resources
Background
Riparian buffers are strips of vegetation adjacent to rivers and streams that filter sediment and pollutants from land runoff. These absorbent borders protect both human and natural interests by creating a buffer between land use and stream ecosystems.
- decrease levels of excess nutrients (such as nitrogen and phosphorous) to keep algal growths from entering our waterways.
- promote increased infiltration, recharging groundwater.
- reduce erosion, decreasing the sediment running into streams and avoiding the loss of valuable acreage.
- shade streams, regulating water temperatures and protecting thermally sensitive aquatic life. This includes recreationally valuable cold-water fish like trout!
- slow and absorb flood waters along rivers, protecting downstream developments from dangerous storm surges.
- deter wildlife from entering streams, thereby reducing fecal bacteria in the water.
The EPA lists riparian buffers as a best management practice for controlling some pollutants like nitrogen. However, riparian buffer filtration efficiency varies by pollutant, making it difficult to set blanket width and content restrictions for the zones. For example, phosphorus and pesticides tend to reach streams through surface runoff, requiring wider riparian zones to trap polluted sediment. Contrastingly, nitrates tend to escape into streams through groundwater, making root depth and soil composition more important than surface land cover for denitrification. The required width of a riparian buffer varies depending on its intended functions, grade of the slope, and soil quality. To avoid erosion, the required border may be as narrow as 30 feet, but if the zone is intended to filter pollutants and sediment and provide flood control, the area required is about 100 feet. In general, the accepted width of a healthy riparian buffer is 100 feet, a distance that will remove roughly 60% of pollutants and provide adequate cover for wildlife. To maximize effectiveness, this zone should be a mixture of forest, shrub, and grasses to filter both surface sediment and subterranean pollutants while providing shade and a natural haven for wildlife. <More below>
Lake Linganore Stream Buffer Ordinance (Frederick County, MD): Lake Linganore provides most of the drinking water for Frederick County residents, yet violates federal and state limits for phosphorus and sediment pollution. In 2007, Potomac Conservancy successfully advocated for a law creating a 100 to 175 foot buffer along all waterbodies in the Lake Linganore watershed, which will help protect drinking water and prevent further pollution.
Frederick County Stream Buffer Ordinance (Frederick County, MD): Following the successful establishment of the Lake Linganore Stream Buffer Ordinance, Potomac Conservancy successfully advocated for expanded riparian buffers. Now, a new county-wide ordinance requires 100 to 175 foot buffer along all waterbodies in Frederick County, MD.
Virginia Department of Forestry – Riparian Forest Buffers (RFB) Contains a wide variety of information, including: creating and maintaining RFBs; Virginia tax credits for RFBs; RFB project case studies; the science behind RFBs; and more.
Maryland Cooperative Extension- Riparian Buffer Systems Contains a wide variety of information, including: seed and plant suppliers (nation-wide); an overview as to what riparian buffers are, their functions and values, establishment, recommended species, and incentive programs; the Maryland Riparian Buffer Systems Manual; fact sheets and more.
The Alliance for the Chesapeake Bay – Riparian Buffers: Linking Land and Water This free downloadable 3.6 MB report produced by the Alliance for the Chesapeake Bay, US Forest Service, Forestry Work Group, and Chesapeake Bay Program thoroughly explains the functions and benefits of riparian forest buffers. This report also discusses the Chesapeake Bay Riparian Forest Initiative and future roles and goals of Chesapeake Bay partners in accelerating riparian buffer establishment and conservation.
US Forest Service- Riparian Forest Buffers: Function and Design for the Protection and Enhancement of Water Resources Describes the many functions and benefits of riparian forest buffers pertaining to water quality and provides establishment guidelines.
The Value of Riparian Forest Buffers in the Chesapeake Bay Watershed: An Economic Framework for Policy-making An advanced technical paper prepared for the Economics and the Chesapeake Bay Workbook Series, this report reviews the functions and benefits of riparian forest buffers, the costs of riparian restoration, “Willingness to Pay”, and a brief section on Public Policy.
Riparian Buffer Width, Vegetative Cover, and Nitrogen Removal Effectiveness: A Review of Current Science and Regulations. United States Environmental Protection Agency, 2005.
Riparian Buffers: What are They and How do They Work? Department of Soil Science, NCSU, 2007. http://www.soil.ncsu.edu/publications/BMPs/buffer.html
Introduction to Riparian Buffers.