HR: 1340h
AN: B33D-1063    [Abstracts]
TI: Stochastic Controls on Nitrate Transport and Cycling
AU: * Botter, G
EM: botter@idra.unipd.it
AF: Dipartimento di Ingegneria Idraulica, Marittima, Ambientale e Geotecnica, Universitá di Padova, via Loredan, 20, Padova, I-35131 Italy
AU: Settin, T
EM: settin@idra.unipd.it
AF: Dipartimento di Ingegneria Idraulica, Marittima, Ambientale e Geotecnica, Universitá di Padova, via Loredan, 20, Padova, I-35131 Italy
AU: Alessi Celegon, E
EM: elisa.alessicelegon@unipd.it
AF: Dipartimento di Ingegneria Idraulica, Marittima, Ambientale e Geotecnica, Universitá di Padova, via Loredan, 20, Padova, I-35131 Italy
AU: Marani, M
EM: marani@idra.unipd.it
AF: Dipartimento di Ingegneria Idraulica, Marittima, Ambientale e Geotecnica, Universitá di Padova, via Loredan, 20, Padova, I-35131 Italy
AU: Rinaldo, A
EM: rinaldo@idra.unipd.it
AF: Dipartimento di Ingegneria Idraulica, Marittima, Ambientale e Geotecnica, Universitá di Padova, via Loredan, 20, Padova, I-35131 Italy
AB: In this paper, the impact of nutrient inputs on basin-scale nitrates losses is investigated in a probabilistic framework by means of a continuous, geomorphologically based, Montecarlo approach, which explicitly tackles the random character of the processes controlling nitrates generation, transformation and transport in river basins. This is obtained by coupling the stochastic generation of climatic and rainfall series with simplified hydrologic and biogeochemical models operating at the hillslope scale. Special attention is devoted to the spatial and temporal variability of nitrogen sources of agricultural origin and to the effect of temporally distributed rainfall fields on the ensuing nitrates leaching. The influence of random climatic variables on bio-geochemical processes affecting the nitrogen cycle in the soil-water system (e.g. plant uptake, nitrification and denitrification, mineralization), is also considered. The approach developed has been applied to a catchment located in North-Eastern Italy and is used to provide probabilistic estimates of the NO_3 load transferred downstream, which is received and accumulated in the Venice lagoon. We found that the nitrogen load introduced by fertilizations significantly affects the pdf of the nitrates content in the soil moisture, leading to prolonged risks of increased nitrates leaching from soil. The model allowed the estimation of the impact of different practices on the probabilistic structure of the basin-scale hydrologic and chemical response. As a result, the return period of the water volumes and of the nitrates loads released into the Venice lagoon has been linked directly to the ongoing climatic, pluviometric and agricultural regimes, with relevant implications for environmental planning activities aimed at achieving sustainable management practices.
DE: 0469 Nitrogen cycling
DE: 1615 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912)
DE: 1866 Soil moisture
DE: 1869 Stochastic hydrology
SC: Biogeosciences [B]
MN: Fall Meeting 2005