Field Testing the Riparian Ecosystem Management Model on a Riparian Buffer in the North CarolinaUpper Coastal Plain

Abstract

AbstractThe riparian ecosystem management model (REMM) was field tested using five years (2005‐2009) of measured hydrologic and water quality data on a riparian buffer located in the Tar‐Pamlico River Basin, North Carolina. The buffer site received NO3‐N loading from an agricultural field that was fertilized with inorganic fertilizer. Field results showed the buffer reduced groundwater NO3‐N concentration moving to the stream over a five‐year period. REMM was calibrated hydrologically using daily field‐measured water table depths (WTDs), and with monthly NO3‐N concentrations in groundwater wells. Results showed simulated WTDs and NO3‐N concentrations in good agreement with measured values. The mean absolute error and Willmott's index of agreement for WTDs varied from 13‐45 cm and 0.72‐0.92, respectively, while the root mean square error and Willmott's index of agreement for NO3‐N concentrations ranged from 1.04‐5.92 mg/l and 0.1‐0.86, respectively, over the five‐year period. REMM predicted plant nitrogen (N) uptake and denitrification were within ranges reported in other riparian buffer field studies. The calibrated and validated REMM was used to simulate 33 years of buffer performance at the site. Results showed that on average the buffer reduced NO3‐N concentrations from 12 mg/l at the field edge to 0.7 mg/l at the stream edge over the simulation period, while the total N and NO3‐N load reductions from the field edge to the stream were 77 and 82%, respectively.