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Science of the Total Environment
Hubert Kieken
N°375/2007. Science of Total Environment, 2007.

Article Long term prospective of the Seine River system: Confronting climatic and direct anthropogenic changes written by Ducharne,A., C. Baubion, M. Benoit, G. Billen, N. Brisson, J. Garnier, H. Kieken, S. Lebonvallet, E. Ledoux, B. Mary, C. Mignolet, X. Poux, E. Sauboua, C. Schott, S. Théry, P. Viennot.

To explore the evolution of a human impacted river, the Seine (France), over the 21st century, three driving factors were examined: climate, agriculture, and point source inputs of domestic and industrial origin. Three future scenarios were constructed, by modification of a baseline representative of recent conditions. A climate change scenario, based on simulations by a general circulation model driven by the SRES-A2 scenario of radiative forcing, accounts for an average warming of + 3.3 °C over the watershed and marked winter increase and summer decrease in precipitation. To illustrate a possible reduction in nitrate pollution from agricultural origin, a scenario of good agricultural practices was considered, introducing catch crops and a 20% decrease in nitrogen fertilisation. Future point source pollution was estimated following the assumptions embedded in scenario SRES-A2 regarding demographic, economic and technologic changes, leading to reductions of 30 to 75% compared to 2000, depending on the pollutants. Four models, addressing separate components of the river system (agronomical model, hydrogeological model, land surface model and water quality model), were used to analyse the relative impact of these scenarios on water quality, in light of their impact on hydrology and crop production.