Physically Based Model Of Soil Erosion And Pollutant Dynamics At A Basin Scale
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M. Ferraresi & S. Longo
In this paper we describe a conceptual model for evaluating sediment transport and pollutants dynamics (BOD, P and N) at a basin scale. The sediment transport model is physically based; the pollutant dynamics model is based on an integral and simplified form of the complex equations. The model was numerically implemented and applied to four catchments in the Po River Area, with extensions ranging from 460–2150 km 2 . The topology is described by DEM with cells of 250x250 m 2 . The time step is 24 h. The model was calibrated using data measured in the main streams in the period 1993–1999. Keywords: pollutant dynamics; sediment transport; basin management. 1 Introduction The study \“Analysis of floods in relation to factors influencing nourishing compounds in the basins of the tributaries of Po River”, developed by Agenzia Regionale Prevenzione e Ambiente dell’Emilia-Romagna (ARPA ) reports on sediment transport and quality of surface water in the main basins in Emilia Romagna, through numerical models. The analysed chemical parameters are Nitrogen, as ammonia, nitric and nitrous, Phosphorus and BOD, hereafter defined as nutrients, and sediment transport. Due to the large time span (1993-99), and large modelled areas (more than 6000 km 2 ) of the basins (Nure, Taro, Secchia and Panaro rivers), the available information allowed only some simplified representations of the phenomena. In the full model stream and catchment processes were separated (but linked): in the present paper only sediment transport and chemical dynamics (nutrients) in the catchment are described. A hydrologic module (ARPA ) is used to model fluid discharge on a daily rate.
pollutant dynamics; sediment transport; basin management.