PROFILE

BMP Manual reference: BMP 6.47.1

Concept
Riparian buffers are permanent areas of native trees and shrubs adjacent to streams, lakes, ponds, and/or wetlands. They provide a wide range of environmental “services” and, as a result are of considerable economic value. The most effective buffers are characterized by high species density, diversity, and bio-productivity.

Stormwater Function
• Volume Reduction: Medium
• Recharge: Medium
• Peak Rate Control: Low/Medium
• Water Quality: Medium/High

Potential Applications
• Residential: Yes
• Commercial: Yes
• Ultra Urban: Yes
• Industrial: Yes
• Retrofit: Yes
• Highway/Road: Limited

Site:
• Bullfrog Creek,
  Harleysville Montgomery County, PA

DETAILS

Description
Often referred to as a riparian corridor or forested buffer, a riparian buffer is the area of land next to a waterway - the streambanks and floodplain. In a natural state, these areas are typically covered with trees, shrubs, and other types of local vegetation, all of which serve to create a healthy ecosystem, slow down and absorb rainwater, trap and remove pollutants, provide shade, and prevent streambank erosion.

Benefits
Scientific research has identified many benefits to protecting and restoring riparian buffer areas. Buffers have been found to:

• Reduce flood damage by increasing storage and infiltration of stormwaters and slowing their velocity
• Protect drinking water by filtering out pollution and helping combat drought conditions
• Increase property values by providing natural enhancements that drive up property values and increase local tax revenues
• Reduce streambank erosion by providing root systems that stabilize streambanks and by slowing down runoff
• Cool stream waters by providing shade; shaded, cooler waters mean healthier streams, particularly for temperature-sensitive fish such as trout
• Improve stream habitat for fish and other aquatic life by providing leaves, sticks, and other natural debris that act as food, shelter, and habitat and support the food chain
• Filter pollutants including sediment, nutrients, toxics, and other contaminants that could get into the aquatic system and be harmful to environmental and human health
• Create recreational opportunities by improving the overall health and aesthetic appeal of waterways

Why protect existing buffers and restore degraded buffers:
In addition to the many benefits provided by protecting existing buffers, research has shown that stream damage can be minimized and water quality enhanced by installing/restoring riparian buffers where they have been previously removed. Science clearly demonstrates that healthy headwaters are essential to the health of stream and river ecosystems and that protecting these headwater streams with forested buffer zones benefit water resources and citizen health. Researchers from the Stroud Center estimate that the cumulative effects of returning Pennsylvania streams to their natural, fully forested state could have a dramatic effect on water quality: studies showed that buffers not only prevented pollutants from reaching waterways, but also that forested stream segments ability to remove nitrogen from the water was 200 to 800% greater than non-forested segments! When you consider the numerous other cost saving, environmental service, and quality of life benefits buffers provide, it is hard to argue against their protection.

Cost considerations:
Restoring forested buffers requires an initial investment in planning, plant materials, tools, and labor—although many efforts involve donated materials and volunteer labor and there are an increasing number of federal and state incentives available that support start up costs. Establishment and maintenance costs to consider include site preparation, tree planting, second year reinforcement planting, and additional ongoing maintenance.

Planning
Effective buffers are characterized by high species density, high species diversity, and high bio-productivity as a transition between aquatic and upland environments. Project designers should take into account the benefits or services provided by the buffer and apply these to their project goals. Priorities for riparian buffer use should be established early on in the planning stages. Some important considerations when establishing priorities are:

• Habitat – Restoring a buffer for habitat enhancement will require a different restoration strategy than for restoring a buffer for increased water quality.
• Stream Size – A majority of Pennsylvania’s stream miles is comprised of small streams (first, second, and third order), which may be priority areas to reduce nutrients. Establishing riparian buffers along these headwater streams will reduce the high nutrient loads relative to flow volumes typical of small streams.
• Continuous Buffers - Establishing continuous riparian forest buffers in the landscape should be given a higher priority than establishing larger but fragmented buffers. Continuous buffers provide better stream shading and water quality protection, as well as corridors for the movement of wildlife.
• Degree of Degradation – Urban streams are usually buried or piped. Streams in areas without forests, such as pastures, may benefit the most from buffer restoration, as sources of headwater streams. Highly urbanized/altered streams may not be able to provide high levels of pollution control.
• Loading Rates - The removal of pollutants may be highest where nutrient and sediment loading are the highest.
• Land Use – Adjacent land uses will influence Buffer Width and Vegetation types used to establish a riparian buffer. Three-zone riparian-forested buffers may be the ideal, but are not always be feasible to establish, especially in urban situations.

Maintenance issues:
Watering new plantings and removing invasive weeds are the primary maintenance requirement for restored riparian buffers. Ongoing maintenance activities for all buffers may include selective cutting and/or pruning and replanting bare spots or unsuccessful trees and shrubs. Riparian buffer areas should not be mowed frequently--only about once per year for newly created buffer areas. Existing, mature riparian areas should require no mowing at all. More details on maintenance considerations can be found in the PA DEP Manual http://www.stormwaterpa.org/assets/media/BMP_manual/chapter_6/Chapter_6-7-1.pdf

RESOURCES

PA DEP Manual BMP 6.7.1: Riparian Buffer Restoration

The Non-Structural Approach
PA DEP Manual BMP 5.4.2: Protect /Conserve/Enhance Riparian Areas

Project Headwaters Case Study

Stroud Center Research Report: Protecting Headwaters

Chesapeake Bay Foundation Report: Forested Buffers—The Key to Clean Streams

The State of Chesapeake Bay Forests Report

PA Buffers 100 Campaign

PA Stream Releaf Program: Forest Buffer Toolkit