Groundwater nitrate reductions within upstream and downstream sections of a riparian buffer

► The study supports properly designed riparian buffers as an effective BMP for protecting streams from groundwater NO3−-N. ► Both buffer sections (60 m and 45 m wide) showed significant removal of groundwater NO3−-N. ► All evaluations indicated both buffer sections were suitable for NO3−-N removal via denitrification and dilution was minimal. ► Highest NO3−-N removal rates were measured in Section 2, which was narrow but located in a more ideal landscape position. ► Conservation programs should consider landscape position over width to maximize water quality protection.