BUFFER
RESTORATION
GUIDE
The health of any waterbody depends upon the upland area that drains into it.
This guide is intended to assist public and private property owners in RI and southeast MA who are interested in restoring and improving buffers along a river, pond, lake or the coast. While this guide is not an exhaustive resource, it is intended to give buffer property owners enough information and resources to design and implement their own restoration project.
This guide was developed by the SNEP Network. The SNEP Network is a project of the New England Environmental Finance Center.
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Property owners who need or
want more assistance with designing and implementing a buffer restoration plan for their property may contact the project partners listed at the end of this guide.
WHAT IS A BUFFER
A buffer is the land next to a waterbody that is vegetated with trees, shrubs, grasses, ferns and other perennials, with a natural layer of previous years’ growth. This vegetation protects the waterbody in a number of ways: by slowing runoff from upland areas and filtering contaminants, and by stabilizing stream banks and providing shade.
Protect What You Have
It’s usually cheaper and easier to protect an existing buffer than to restore a new one. Existing vegetated buffers are already helping to improve water quality.
TYPES OF BUFFERS
Riverine – or “riparian” – buffers are found along streams, rivers, ponds or wetlands where water levels may change dramatically seasonally and during wet vs. dry weather conditions. Vegetation living here is able to withstand periodic wet soils.
Coastal buffers can be quite diverse depending upon whether they are located next to a highly exposed ocean waterfront or a more protected cove, embayment, or salt marsh. Typically the vegetation growing here is able to withstand wind, varying levels of salt spray and can grow in a variety of low nutrient soils, like sand or clay. The most salt tolerant plants can withstand occasionally being submerged in saltwater.
BUFFER SIZE
Buffers of 35’ to 100’ width are considered an ideal minimum width to protect water quality, and the State of Rhode Island uses a standard of 200’ riparian buffer as protective for drinking water supply tributaries, as well as water quality and some habitat functions. Where lot size prevents buffers of these widths, restoring the area immediately next to the water body to stabilize the shoreline can reduce bank erosion and provide some water quality and habitat benefits.
BENEFITS OF BUFFERS
The environmental and economic benefits of buffers are well documented, and will help:
One of the greatest benefits of buffers is their potential for reducing water pollution by encouraging rain runoff – and pollutants that it may pick up along the way – to infiltrate into the soil rather than running off into the waterbody. Many rivers, streams and coastal waters in the state and region are impaired due to high levels of pollutants that are carried by stormwater runoff. Vegetated buffers act like sponges, soaking in rain water running off the nearby land, and capturing nutrients (nitrogen and phosphorus), sediment and other pollutants.
Buffers improve wildlife habitat in several ways. By capturing pollutants and sediment before they enter a waterbody, water quality in the stream or bay is improved which creates better aquatic habitat for pollution-intolerant fish and aquatic invertebrates. A riparian buffer helps to supply organic materials (leaves and woody debris), which provide food for aquatic invertebrates (which, in turn, provide food for wildlife). The buffer can also provide shade from trees that can lower water temperatures, improving habitat for species that require cold water habitat like brook trout. Cold water fish habitat is increasingly threatened by increasing temperatures and stream alterations. A buffer serves as the basis for a more diverse structural habitat for all aquatic life.
Buffers provide food, shelter, water, and breeding sites for birds, mammals, amphibians, and reptiles. The species that are found in buffer habitats largely depends on the type and size of the water body (wetland, river, stream, lake, pond or coastal waters), as well as the habitat within the riparian buffer (diversity of tree species, availability of nest and perch sites, frequency of flooding, etc.). While buffers improve wildlife habitat for many species, they can also deter geese which is an added benefit, as geese are frequently a source of nutrient and bacteria pollution.
Buffers can help reduce flooding in a variety of ways. By replacing currently-paved or mowed grassy areas with a diversity of vegetation, buffers increase the absorptive capacity of the land, allowing rain runoff to soak into the ground versus running off directly into the waterbody. Roots of trees and shrubs help absorb water from the soil when water levels are high. And, leaves (particularly on larger trees) will intercept rain and snow, reducing the amount of precipitation that reaches the ground.
Buffers reduce erosion, which both conserves topsoil and lessens the amount of sediment in streams and rivers. The roots of herbaceous and woody plants (such as trees and shrubs) strengthen the stream bank by going through the topsoil and into a stream bank’s weathered or fractured bedrock and other more stable strata. This strengthens the stream bank and reduces erosion.
A well-designed buffer can look great! Being intentional and thoughtful about the design of your buffer area can result in a buffer that not only improves water quality and creates habitat but that also improves the aesthetics of the area near a waterbody. Even a “wild” looking buffer, with a mix of interesting and colorful plant life, can be beautiful and enhance the look of parks, backyards and other open spaces. Improved wildlife habitat can also provide wildlife viewing opportunities.
Buffer restoration can be part of a comprehensive approach to reduce pollutants and sediment in stormwater, and to restore a watershed’s hydrological cycle. For municipalities with impaired waterbodies (such as those for which a watershed study or Total Maximum Daily Load (TMDL) study has been developed) restoring, expanding and improving buffers can help address specific pollution problems in targeted locations. Buffer restoration can also help avoid future water quality issues.
If your goal is to enhance buffers to address a particular pollutant (such as nutrients, bacteria or sediment) the design and plans for your buffer may be tailored with specific characteristics of that pollutant in mind. Buffer restoration is a “nature-based solution” to non-point sources of pollution such as stormwater runoff, and may be accepted as part of a comprehensive approach to meet regulatory requirements.
Rhode Island’s Freshwater Wetlands Rules in effect July 2022 define buffers as “an area of undeveloped vegetated land adjacent to a freshwater wetland that is to be retained in its natural undisturbed condition or is to be created to resemble a naturally occurring vegetated area”. To ensure compliance with these and other regulations, be sure to consult the applicable regulations before proceeding with your buffer restoration project.
UNDERSTANDING THE PROCESS
If you’re sold on the benefits of buffer restoration on your site, don’t grab the shovel just yet; there are several things you’ll want to think about first. What are the current conditions of your site? How is it used, or how do you want it to be used? What are your goals for the project? Your budget? And which buffer option makes the most sense? Who will do the work? And, how will you put it all together into a successful project? Here’s one way to approach the process:
If the buffer project you envision is beyond you or your staff’s design or engineering capabilities, or if you don’t have the human resources to complete the work, you may want to bring in professional help.
