The trees, shrubs and other plants that grow next to streams and rivers are critical to the health of the Chesapeake Bay. These buffers prevent pollution from entering waterways, stabilize stream banks, provide food and habitat to wildlife and keep streams cool during hot weather.
What are stream buffers?
Stream buffers, also known as forest buffers or riparian buffers, are the trees, shrubs and other plants that grow next to streams and rivers. They are planted in riparian zones, which is the area on the banks of a river where this type of vegetation naturally grows.
Why are stream buffers important?
Stream buffers are critical to clean water: they prevent pollution from entering waterways and stabilize stream banks. Also vital to wildlife, they provide critters with food and habitat and shade streams to the benefit of sensitive aquatic species.
Without stream buffers, polluted runoff from farms and developed areas would flow directly into rivers and streams. Stream buffers are a waterway’s last line of defense against pollution that washes off the land.
Trees and shrubs slow the flow of stormwater runoff, trapping sediment and allowing polluted water to soak into the forest floor’s sponge-like soil.
Plant roots absorb nutrient pollution and store it in plant leaves and limbs.
Stabilizing stream banks
The deep root systems of streamside trees and shrubs hold soil in place, stabilizing stream banks and reducing the amount of sand, silt and sediment that can wash into waterways. Stream buffers also protect those on land from rising floodwaters by deflecting heavy river flow during large storms.
Food and habitat for wildlife
The trees, shrubs and other plants that make up stream buffers form layers of diverse habitats between land and water. More than half of the Chesapeake Bay region’s native species—including wood ducks, bald eagles, turtles and amphibians—depend on buffers for food, shelter and access to water at some point in their lives. Stream buffers also offer safe migration paths for wildlife, creating forest “corridors” that are critical to many species.
The leaf litter, seeds and other plant materials that stream buffers drop into the water form the foundation of the freshwater food chain, and fallen branches, logs and woody debris can create habitat for underwater critters. Insects, amphibians, crustaceans and small fish depend on this debris for food, shelter and spawning grounds. These small creatures serve as essential prey for larger species. Some small filter-feeders also process the excess pollution that is common in local waterways.
Shade for streams
In summer, the leafy canopies of stream buffers shade rivers and streams. This shade helps keep water temperatures cool and consistent. Without it, water temperatures would rise rapidly, fueling the growth of harmful algae blooms and stressing sensitive species. Brook trout, for instance, live in cool, clear water, and depend on the shade that stream buffers provide. Cooler water can also hold more oxygen, which aquatic species need to survive.
How are stream buffers being restored?
Because stream buffers can improve the health of local rivers and streams, stream buffer restoration is a critical part of cleaning up the Chesapeake Bay. Restoring stream buffers can be a cost-effective way to reduce pollution. Unlike some other conservation practices, the benefits of stream buffers increase over time as trees and shrubs grow and mature.
Newly planted stream buffers must be maintained for trees and shrubs to have the best chance of survival. Pruning and weeding, for instance, can help stream buffers grow stronger, making them more resilient to invasive species and other threats and better able to capture polluted runoff.
Currently, an estimated 55 percent of the watershed's 288,000 miles of stream banks and shorelines have stream buffers in place. But scientists have found that rivers and streams are not protected until at least 70 percent of their edges are buffered. Stream buffers have disappeared along many rivers and streams because of agriculture, development and other human activities.
Some programs provide financial incentives to landowners who plant stream buffers on their properties. The Conservation Reserve Enhancement Program (CREP), for instance, pays agricultural landowners to plant and maintain stream buffers on their farms.
New geo-spatial tools are also available to help target, monitor and map stream buffers across the watershed. These tools, along with local and state streamside forest policies, will ensure that stream buffer restoration and conservation remains effective.
What you can do
To support stream buffers in the Bay watershed, consider planting streamside trees and shrubs to create more wildlife habitat. You can also choose and use native plants to support the plants and animals that have adapted to this region.
The Chesapeake Bay Program is committed to restoring 900 miles of riparian forests in the watershed each year through its Forest Buffers Outcome. Although progress has been made, plantings have slowed in recent years due to a number of factors, such as a lack of resources, the high price of crop commodities and the tendency of the agricultural community to plant grass buffers rather than forested ones. In 2020, 169 miles of forest buffers were planted along rivers and streams in the Chesapeake watershed, which is 731 miles below the 900-mile-per-year target.