Community Research and Development Information Service - CORDIS


ANSWERS-2000: Nonpoint Source Nutrient Planning Model

Funded under: FP5-EESD


ANSWERS-2000, a nonpoint source planning model was modified to simulate long-term nitrogen (N) and phosphorus (P) transport from rural watersheds. The model simulates infiltration, evapotranspiration, percolation, and runoff and losses of nitrate, adsorbed and dissolved ammonium, adsorbed total Kjeldahl N (TKN), and adsorbed and dissolved P losses. Eight soil nutrient pools are modelled: stable and active organic N, nitrate, and ammonium, and stable and active mineral, organic and exchangeable P. The model was validated on two small watersheds without calibration and on a large watershed with calibration of only the sediment detachment parameters. Predicted cumulative runoff, sediment, nitrate, dissolved ammonium, adsorbed TKN, and orthophosphorus P losses were within a factor of two of observed values (-40 to +44% of observed values). Predictions of individual runoff event losses were not as accurate (-98 to +250%). The model seriously overpredicted adsorbed ammonium losses by up to 97% and additional work is recommended on this submodel. In a practical application, the use of the model in evaluating the cost effectiveness of alternative management scenarios was demonstrated.

Additional information

Authors: BOURAOUI F, JRC - Environment Institute, Soil and Wastes Unit, Ispra (IT);DILLAHA T, Virginia Polytechnic Institute and State University, Biological Systems Engineering Department, Blacksberg (US)
Bibliographic Reference: Article: Journal of Environmental Engineering, further details unavailable
Availability: Journal of Environmental Engineering
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