Riparian Zone and Stream Restoration

Introduction

Riparian Zone and Stream Restoration

Riparian zones are stream channels and corridors. With the right techniques, these areas can be restored and reconstructed to improve habitat for fish and to stabilize the banks against erosion and gouging.

With the right techniques, stream channels and corridors (riparian zones) can be restored and reconstructed to improve habitat for fish and to stabilize banks against erosion and incision (gouging). Such efforts can serve to benefit water quality; however, the effectiveness of restoration for improving surface or groundwater quality has not been thoroughly assessed.

The same techniques can be used to remove or reduce nutrients that have detrimental effects on human health and aquatic life. For example, nitrogen, which is required in small amounts for growth of living organisms, can pose health risks when concentrations are high. Excess nitrogen enters streams from fertilizer runoff, animal wastes, sewer lines, and atmospheric deposition of nitrous oxides from fossil fuel combustion (e.g., automobile exhaust).

Ecological restoration is used to enhance the ability of a stream to naturally remove nitrogen through denitrification, a process performed naturally by microorganisms in the water and subsurface. EPA scientists are examining the effects of stream restoration on water quality in Baltimore, Maryland, where a degraded urban stream (Minebank Run) has been restored to stabilize stream banks and reduce further channel erosion.

The objectives of the Minebank Run project were to assess the ecosystem benefits of restoration and to identify stream restoration methods that enhance nitrogen control or otherwise improve water quality. When such methods are identified, EPA can develop ecologically based guidelines for stream restoration and share this information with land managers who have a need to restore the ecological health of streams and riparian zones, and improve water quality for residents in the watershed.