Hydrologic analysis of a riparian buffer enrolled in conservation reserve enhancement program in North Carolina using Riparian Ecosystem Management Model (REMM)

Conservation practices such as the installation of riparian buffers along streams are known to reduce the impacts of non-point source pollutants such as nitrogen and phosphorus. A riparian buffer enrolled in the Conservation Reserve Enhancement Program in North Carolina, located in the Tar-Pamlico Watershed, has been monitored for hydrology and water quality since 2005. This buffer site received nitrogen and phosphorus loads from an upland source of inorganic fertilizer for crops like cotton, peanut and soybean. Results from the field studies have shown that the buffers are able to reduce nitrate-nitrogen loads to the streams. The hydrology is a driving factor for biogeochemical reduction of pollutants in the buffers, which often leads to highly variable performance in terms of nitrate-nitrogen reduction. The Riparian Ecosystem Management Model (REMM) was calibrated and will be validated to enhance the understanding of surface and subsurface hydrologic patterns at this buffer. The results showed the simulated water table depths in good agreement with field measured water table depths in block 1 of the research site. The average absolute error (AAE) was 92 mm for the field edge buffer, 120 mm for mid-buffer and 137 mm for the stream buffer zone over a three year period (2005-2007). Characterizing the hydrology at the site was the first step in our attempt to model nitrate losses from the buffer system.