BIOFILTERS (Bioswales, Vegetative Buffers, & Constructed Wetlands) For Storm Water Discharge Pollution Removal
State of Oregn Department of Environmental Quality , 2003
This document is an attempt to compile the best available information on the design and use of biofilters (bioswales, vegetated filter strips, and constructed wetlands) so that those sites that may have an application of one or the other of these vegetated filtering systems will have information to make the best decision on the design, construction, implementation, and maintenance of these Best Management Practices. It is not a design manual but a practical, based on experience and knowledge of sites that implemented these BMPs, useful information on what works and does not work when designing, constructing, and operating them. Research is needed to determine the effect these BMPs will have on turbidity and other pollutants but there are indications that their effect will be positive and of environmental benefit. Bioswales and constructed wetlands are being used more and more to address pollutants in storm water runoff. Many installations of these BMPs have failed or have not been as successful as was hoped when their use was first contemplated. Most of the limited success or failures can be attributed to insufficient information being available or to bad or no expert input into the design, construction, vegetating, or maintenance of the bioswale or constructed wetland. It is hoped that this document will provide that useful information and reason to seek out those that have the expertise to be of help. As long as a constructed wetland is not built in a natural wetland, waterway, or floodplain, EPA and the Oregon Division of State Lands views the wetland as a private treatment method that does not require wetland permitting and it is treated different from the way a natural wetland is treated. Additional copies of this document are available on the internet at http://www.deq.state.or.us/nwr/stormwater.htm.