| Abstract | The capability of eight nutrient models to predict annual nutrient losses (nitrogen and phosphorus) at catchment scale have been studied in the EUROHARP project. The methodologies involved in these models differ profoundly in their complexity, level of process representation and data requirements. This evaluation is focused on model performance in three core catchments: the Vansjo-Hobol (Norway), the Ouse ( Yorkshire, UK) and the Enza (Italy). These three different model applications have been evaluated by comparing calculated annual nutrient loads (total N or nitrate and total P), based on observed flow and total nitrogen or nitrate and total phosphorus concentrations, and the annual nutrient loads that were simulated by the eight nutrient models. Four statistics have been applied for this purpose: the root mean squared error (RMSE), the mean absolute error (MAE), the mean error (ME), and Nash-Sutcliffe's model efficiency (NS). The results show that all model approaches can predict the calculated annual discharges. Depending on the observed statistics ( RMSE, MAE, ME and NS) the scores of the model application differed, therefore no overall 'best model' could be identified. Although the water and nutrient loads from (sub) catchments can be predicted, the modelled pathways of nutrients within agricultural land and the nutrient losses to surface waters from agricultural land vary among the catchments and among those model approaches which are able to make this distinction. |
| Authors | SCHOUMANS O., SILGRAM M., WALVOORT D., GROENENDIJK P., BOURAOUI F., LO PORTO A., LE GALL G., ARHEIMER B., MIMIKOU M., ZWEYNERT U., BORGVANG S. |
| Text | 42316 2009 10.1039/b823240g ISI Web of Science WOS 000264098400009 EVALUATION OF THE DIFFERENCE OF EIGHT MODEL APPLICATION TO ASSESS DIFFUSE ANNUAL NUTRIENT LOSSES FROM AGRICULTURAL LAND SCHOUMANS O., SILGRAM M., WALVOORT D., GROENENDIJK P., BOURAOUI F., LO PORTO A., LE GALL G., ARHEIMER B., MIMIKOU M., ZWEYNERT U., BORGVANG S. Alterra, Wageningen, Netherlands ADAS Ltd., Wergs Road, Wolverhampton, UK EC JRC, Ispra, Italy National Environmental Research Institute, Silkeborg, Denmark Instituto di Ricerca sulle Acque, Bari, Italy Beture Cerec Saint Quentin en Yvelines, Lyon, France Swedish Meteorological and Hydrological Institute, Norrkooping, Sweden Swedish University of Agricultural Sciences, Uppsala, Sweden NTUA, Athens, Greece Institut fuer Gewaesseroekologie und Binnenfischerei, Berlin, Germany KMM, Belfast, Northern Ireland The capability of eight nutrient models to predict annual nutrient losses nitrogen and phosphorus at catchment scale have been studied in the EUROHARP project. The methodologies involved in these models differ profoundly in their complexity, level of process representation and data requirements. This evaluation is focused on model performance in three core catchments the Vansjo Hobol Norway , the Ouse Yorkshire, UK and the Enza Italy . These three different model applications have been evaluated by comparing calculated annual nutrient loads total N or nitrate and total P , based on observed flow and total nitrogen or nitrate and total phosphorus concentrations, and the annual nutrient loads that were simulated by the eight nutrient models. Four statistics have been applied for this purpose the root mean squared error RMSE , the mean absolute error MAE , the mean error ME , and Nash Sutcliffe s model efficiency NS . The results show that all model approaches can predict the calculated annual discharges. Depending on the observed statistics RMSE, MAE, ME and NS the scores of the model application differed, therefore no overall best model could be identified. Although the water and nutrient loads from sub catchments can be predicted, the modelled pathways of nutrients within agricultural land and the nutrient losses to surface waters from agricultural land vary among the catchments and among those model approaches which are able to make this distinction. 11 3 Articolo pubblicato JEM_annual_models.pdf Articolo in rivista Royal Society of Chemistry, 1464 0325 Journal of environmental monitoring Print Journal of environmental monitoring Print J. environ. monit. Print Journal of environmental monitoring Print JEM Cambridge. Print Print antonio.loporto LO PORTO ANTONIO TA.P04.005.006 Gestione a scala di bacino delle risorse idriche e sostenibilita dell uso irriguo in agricoltura |
