Riparian Zone Management for Protection of Aquatic Resources

Riparian zones are the margins of streams and other bodies of water. Considered in three dimensions, riparian zones extend lengthwise along the stream, horizontally away from the stream, and vertically upward to the vegetation canopy and downward into the soil.

Waterways create special conditions along their margins that control and influence transfers of energy, nutrients, and sediments between aquatic and terrestrial systems. The unique stream margin habitats are called riparian zones. Many of the problems described as aquatic habitat loss can be mitigated by minimizing disturbance of vegetated riparian buffers. Some of the processes performed by forested riparian buffers include:

• Trapping sediments from land erosion.
• Reducing streambank erosion.
• Trapping and sequestering phosphorus and nitrogen, nutrients that can lead to enrichment of aquatic ecosystems.
• Trapping and processing other contaminants, such as pesticides.
• Storing flood waters.
• Maintaining habitat for fish and other aquatic organisms by moderating water temperatures and providing large woody debris.
• Providing habitat for amphibious and terrestrial organisms.
• Improving the aesthetics of stream corridors.
• Offering recreational opportunities.

No national standard exists for establishment and maintenance of riparian buffers. For buffers to be most effective, managers must consider several issues:

1. Buffers should be continuous along the length of streams. Gaps in forest cover allow direct surface flow to the stream, compromising the protective function of the buffer system.
2. Small headwater streams need particular protection, because they make up the majority of stream miles in any drainage basin, and funnel sediment and nutrients downstream to larger receiving waters.
3. Width of riparian buffers (distance upslope on each bank) may depend on slope of the site; where steeper slopes occur in a buffer, the filtering efficiency decreases, so greater widths are needed. In most states the recommended (or required) buffer width ranges from 25-300 ft.
4. A forested buffer 100 ft wide will trap most of the sediment from a newly constructed gravel road (Swift 1986).

Forestry Best Management Practices (BMPs) have been established by the various states to protect the aquatic resource.