By Nidhee Seernaum, Clean Water Institute Intern, Summer 2022
Riparian buffers, also known as forested buffers, consist of natural vegetation on the edge of streams or along the shoreline of wetlands. The area, known as the riparian zone, protects and separates the stream, lake, or wetland from human as well as natural interferences.
Among the many benefits that these buffers provide, they are known to trap pollutants from runoff and reduce the amount of sediment entering streams, improving water quality. Herbaceous and woody tree roots allow sediment to settle out and prevent soil erosion. Food as organic material and woody debris as habitat are provided for invertebrates, fishes, and wildlife. The water temperature is also controlled by the amount of sunlight reaching the stream through the trees, meaning riparian buffers help keep streams cool during the summer. The impact of flooding is also reduced by riparian zones that store the water. The wider the buffer, the greater the benefits.
Anthropogenic degradation of riparian zones like residential developments or roads has greatly impacted the important physical, biological, ecological functions that those buffers provide. The USDA Forest Service estimates that over one-third of the rivers and streams in Pennsylvania have had their riparian buffers degraded or altered (DEP, 2006). From our own observations over the years at the Clean Water Institute, we have noticed drastic changes in the stream water quality in streams whose riparian zones have been altered. Some streams near agricultural areas in Lycoming County have recently been stripped of their riparian zones, which has greatly increased the number of E.coli bacteria in the water through animal wastes that get washed away in the water with no barrier to trap it.
Grafius Run, one of the urban streams that our team has been monitoring, shows signs of drastic impacts due to the lack of riparian buffers. The stream has been mostly drying the last few summers we have been monitoring it. In addition, a lack of riparian shading makes it difficult for a thriving aquatic environment to develop.
A study by the Chesapeake Bay Foundation of 16 streams in eastern Pennsylvania found that forested streams were more efficient at removing pollutants from water than non-forested streams. In the case of nitrogen pollution, 200-800 times more nitrogen reached the stream in the non-forested segments than reached the stream in the forested segments.
To preserve the water quality of our streams, it is imperative for people to understand the benefits of riparian zones and to spread awareness about it. Municipalities are allowed by Pennsylvania law to adopt land use regulations that protect riparian buffers and maintain the quality of the streams. Through inclusive civic engagement, any concern about a damaged riparian zone must be reported to the municipality for overview and native grasses, shrubs and trees can be replanted to protect the waters.
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