The Iowa Watershed Approach
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What are buffers?
Buffers are established areas of permanent vegetation, within and around fields, and are designed to intercept and filter sediment and nutrients out of surface runoff and shallow groundwater before entering a water course. The vegetation provides habitat for wildlife and creates a recreational and aesthetically pleasing area. One of the primary functions of buffers is to slow surface runoff, trapping 41-100% of the sediment and significantly reducing the phosphorus load. By slowing surface runoff and promoting infiltration, buffers delay downstream flooding and reduce streamflow by 10%. Additionally, when shallow groundwater interacts with the buffer’s root zone, biological processes can remove 48-85% of its nitrate-nitrogen; however, the percent of shallow groundwater that interacts with the root zone could be small. There are many types of buffers which are distinguished by their design and vegetative species, including: riparian forest buffer, filter strips, field borders, field windbreaks, grassed waterways, among others.
Benning, Jamie; TeBockhorst, Kristina; and Johnson, Jason, "Buffers" (2018). Extension and Outreach Publications. 435.
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