I was recently asked to give a talk to the Friends of the Appomattox River. As a forest ecologist, I tried to think of a topic within my realm of study that would interest a group focused on aquatic issues and natural history. I decided to talk about Riparian Buffer Zones – the forested or planted areas around rivers that, as the name suggests, act as buffers between agricultural or urban areas and waterways. A riparian buffer is a legislative term used to designate a planted area bordering a body of water that is implemented to maintain water quality and wildlife habitat.
Plants around rivers and streams have a variety of positive effects on their ecosystem. Their shading moderates stream temperature and light input, especially important to trout habitat and prevention of algal blooms. Their input of logs, wood, and leaves diversifies habitat and substrate types, which increases species diversity. Their roots perform three functions: (1) preventing stream bank erosion, (2) reducing flood risk, and (3) filtering out non-point source pollutants, such as excess leached nitrogen and phosphorus from agricultural systems. The latter, in particular, helps prevent algal blooms, anoxic conditions, and fish kills downstream.
Generally, most audiences immediately recognize the importance of these buffers on large rivers, but buffers are equally important on small headwater streams. Small streams cover much more mileage of a watershed than large streams and also provide the majority of nutrient inputs for larger rivers downstream. Thus, the functioning of large waterways is inherently linked to the function of smaller waterways. In addition, small waterways tend to occur on areas with much steeper slopes, where risk of erosion and topsoil loss is much higher. Best Management Practices, if followed, require loggers to leave a buffer around small streams because of these important considerations. Private landowners, however, often do not recognize this importance, or the tax incentives and cost-shares available, to preserve riparian areas around even very small streams crossing their land.
While the importance of buffers is clear, they come with a cost to the landowner. According to the Natural Resources Conservation Service in Virginia, the average cost of establishing a buffer is $155/acre, but Matt Poirot at the VA Department of Forestry says that tree plantings with tree seedling protectors cost about $900/acre. Costs may include plants, site preparation, weed control, fencing, stream crossings for livestock, and alternate watering sources for livestock. The landowner may also lose production income from the land and lose waterfront access or views.
Thus, a variety of tax incentives, cost-share programs, and conservation easements promoting buffer establishment and maintenance exist at the local, state, and federal level through both governments and non-profits. For more information about specific programs and requirements for landowners in Virginia, go here, and talk to your local Soil and Water Conservation District.
These programs vary in their required buffer width, types of vegetation, and management. A buffer width of 95 feet was recommended by Welsch (1991) as the best width for water quality maintenance. However, such large buffers are sometimes but not always possible because the landowner loses that land’s use for production. Further, larger buffers are generally advised or required on steep slopes, but narrower buffers are often satisfactory on more level topography. Some buffer requirements compromise on this issue by requiring a wide buffer, but the edge furthest from the water can be planted in grass while the edge on the waterway must be forested. Buffers planted in grass are easier to convert back to production, whereas a forested area requires a longer commitment to the buffer’s maintenance and a higher cost to establish. Many buffer regulations only require planting one species (a grass or tree), but some tax incentives and cost-share programs stipulate that more than one species must be planted to promote diversity. Natural riparian areas are incredibly diverse wetland areas, and the best riparian buffer plantings will include fast-growing, flood-tolerant species with large root systems. Many buffer incentive programs also require that the buffer be maintained for a certain period of time, often ten years. By combining multiple cost-shares at the local, state, or federal level, landowners can often get 100% of the cost of buffer establishment re-imbursed, with a hefty tax break to boot!