EVALUATING THE EFFECTIVENESS OF FORESTED RIPARIAN BUFFER ZONES ON NITRATE REMOVAL FROM THE SUBSURFACE

A forested riparian buffer zone is an area of trees, shrubs, and other vegetation separating cropland or pasture from a stream, another body of water, or a groundwater recharge area. These zones are designed and managed to provide shade, restore stream habitat, and to trap and remove nutrients, sediments, pesticides, and other chemicals from surface runoff and subsurface groundwater flows. The current EPA models found that the forested riparian buffer zones are one of the most cost-effective best management practices that lower nutrient and sediment transport to waterways. County and state level soil and water conservation agencies have invested in the establishment of such buffers along agricultural fields with support from various funding sources to reduce nutrient and sediment transport into the Chesapeake Bay. The objectives of this project are to evaluate the effectiveness of forested riparian buffer zones on nitrate removal from shallow groundwater, and to establish a long-term monitoring program of these buffer zones. Two sites were selected for a pilot study in Otsego County, New York that were planted about five years ago. At each site, two transects of piezometers were installed in early summer of 2020 to access the groundwater in the unconfined aquifer, which is made of heterogeneous glacio-fluvial sediments. Water samples were collected every 2-4 weeks between June and November of 2020 and 2021. Field parameters were measured on-site and nitrate concentrations were determined using ion chromatography. The total dissolved solids concentrations decrease across the buffer zone from the field edge toward the stream. However, nitrate concentrations are highly variable and no spatial and temporal patterns are detected through transects. The results are inconclusive after monitoring the sites for two growing seasons. Establishing long-term monitoring in collaboration with farmers, undergraduate colleges, and the county’s soil and water conservation district office can help with understanding the nitrate movement within the buffer zone. The results can provide guidance for establishing new forested riparian buffer zones in areas with heterogeneous glacial deposits.