by the alluvial plains. Overflows as well as direct exchanges at the stream–aquifer
interface from aquifers contribute 55% of the river network discharge at the basin
outlet (Fig. 5).
5 A Two-Century-Long Trajectory of the Seine Basin
The model provides the opportunity to characterise modifications in behaviour of the
Seine hydrosystem under different scenarios combining preselected constraints on
climate, land use and anthropogenic pressure data. It is therefore possible to reconstruct the trajectory of the system from the early 1900s to the end of the current
century. Two scenarios are proposed to re-evaluate water fluxes: (1) a simulation
associated with the first part of the twentieth century (1917–1934), which integrates
past daily climate data as well as modifications in the surface distribution of land use,
and (2) a second one (2083–2100) using climate data derived from a general
circulation model (GCM) forced by the high emission scenario RCP8.5 [5] to
evaluate the response of the Seine system in a context of climate change. Radiative
forcings in RCP8.5 increase throughout the twenty-first century before reaching a
level of 8.5 W m
À2 at the end of the century. Modifications in groundwater
withdrawal rates are also implemented. For the sake of clarity, results from both
Fig. 6 Spatial distribution of stream–aquifer exchanges averaged over the 1993–2010 period. The
main gauging stations of the basin are also displayed
Pluri-annual Water Budget on the Seine Basin: Past, Current and Future Trends
71
interface from aquifers contribute 55% of the river network discharge at the basin
outlet (Fig. 5).
5 A Two-Century-Long Trajectory of the Seine Basin
The model provides the opportunity to characterise modifications in behaviour of the
Seine hydrosystem under different scenarios combining preselected constraints on
climate, land use and anthropogenic pressure data. It is therefore possible to reconstruct the trajectory of the system from the early 1900s to the end of the current
century. Two scenarios are proposed to re-evaluate water fluxes: (1) a simulation
associated with the first part of the twentieth century (1917–1934), which integrates
past daily climate data as well as modifications in the surface distribution of land use,
and (2) a second one (2083–2100) using climate data derived from a general
circulation model (GCM) forced by the high emission scenario RCP8.5 [5] to
evaluate the response of the Seine system in a context of climate change. Radiative
forcings in RCP8.5 increase throughout the twenty-first century before reaching a
level of 8.5 W m
À2 at the end of the century. Modifications in groundwater
withdrawal rates are also implemented. For the sake of clarity, results from both
Fig. 6 Spatial distribution of stream–aquifer exchanges averaged over the 1993–2010 period. The
main gauging stations of the basin are also displayed
Pluri-annual Water Budget on the Seine Basin: Past, Current and Future Trends
71