catchment area, but the external components have been increasing steadily for
50 years (national and European regulations, national and European markets for
agricultural products, decline or recovery of industry and mining, as well as the
evolution of international trade, etc.).
River system refers primarily to the hydrosphere, i.e. the water circulation over a
well-delineated area, the basin watershed. It includes the atmospheric inputs and
water flow components of the drainage network and is separated into (1) the surficial
hydrographic network, from headwater streams to the estuary, including stagnant
systems such as ponds, wetlands, lakes, reservoirs, and canals, (2) shallow and deep
aquifers and their related unsaturated zone. It also includes the terrestrial biosphere
and the pedosphere, which regulate water circulation and provide the river-borne and
groundwater materials, and the aquatic biosphere, from micro-organisms to fish
populations. Finally, the system also includes all the controlling factors that regulate
these fluxes of water and materials and their composition: internal factors, either
natural (e.g. hydrological regime, river morphology) or anthropogenic (e.g. water
abstraction, pollution, hydrological control, and artificialization of river course), and
external factors (e.g. climate change, trans-basin trade, species introduction, etc.). It
can therefore be considered as a socio-ecosystem in the sense of Haberl [5].
Among the six hydrographic basins of metropolitan France, the Seine-Normandy
basin is the most human-impacted (see Sect. 2 of this chapter). It receives the highest
anthropic pressure, due to its industry and agriculture linked to the development of
the urban area of Paris, which has been and still is the economic and social heart of
France. The very poor chemical and ecological status of water in the 1980s led a
small group of researchers to propose a PIREN-Seine, i.e. an interdisciplinary
environmental research programme launched by the French National Centre for
Scientific Research (CNRS), as had already been put in place for the Rhône River,
the Garonne River, and the Alsace plain in 1979 [6]. It was created in 1989 in a
context of insufficient wastewater treatment in the Paris conurbation and new
investment projects in sanitation facilities [7]. Its first achievement consisted in
developing a model, Riverstrahler [8], to dynamically represent the biogeochemical
fluxes of carbon, nitrogen, phosphorus and then silica, for each body of water in the
basin, from headwaters to the Seine outlet, according to constraints such as geomorphology, hydrography, agricultural diffuse sources, and urban discharges. Another
modelling tool, ProSe, was also developed with a transient hydrology on the lower
Seine more dedicated to the Paris conurbation domestic load [9–12]. These tools
have made it possible to bring together research teams on a common object of study,
the entire Seine watershed; the programme has also been a forum for dialogue
between the basin’s institutional partners and researchers, enabling the latter to
make management proposals to establish investment priorities based on the results
of these models [13]. Despite the fact that PIREN programmes have been replaced
by other interdisciplinary programmes, the PIREN-Seine programme has continued
to exist, financially supported by the institutions in charge of the Seine basin
management. Over the past 30 years, it has generated a vast number of publications,
more than 100 PhD theses, hundreds of publications in scientific journals and as
many communications in international workshops and conferences, as well as
Trajectories of the Seine River Basin
3
50 years (national and European regulations, national and European markets for
agricultural products, decline or recovery of industry and mining, as well as the
evolution of international trade, etc.).
River system refers primarily to the hydrosphere, i.e. the water circulation over a
well-delineated area, the basin watershed. It includes the atmospheric inputs and
water flow components of the drainage network and is separated into (1) the surficial
hydrographic network, from headwater streams to the estuary, including stagnant
systems such as ponds, wetlands, lakes, reservoirs, and canals, (2) shallow and deep
aquifers and their related unsaturated zone. It also includes the terrestrial biosphere
and the pedosphere, which regulate water circulation and provide the river-borne and
groundwater materials, and the aquatic biosphere, from micro-organisms to fish
populations. Finally, the system also includes all the controlling factors that regulate
these fluxes of water and materials and their composition: internal factors, either
natural (e.g. hydrological regime, river morphology) or anthropogenic (e.g. water
abstraction, pollution, hydrological control, and artificialization of river course), and
external factors (e.g. climate change, trans-basin trade, species introduction, etc.). It
can therefore be considered as a socio-ecosystem in the sense of Haberl [5].
Among the six hydrographic basins of metropolitan France, the Seine-Normandy
basin is the most human-impacted (see Sect. 2 of this chapter). It receives the highest
anthropic pressure, due to its industry and agriculture linked to the development of
the urban area of Paris, which has been and still is the economic and social heart of
France. The very poor chemical and ecological status of water in the 1980s led a
small group of researchers to propose a PIREN-Seine, i.e. an interdisciplinary
environmental research programme launched by the French National Centre for
Scientific Research (CNRS), as had already been put in place for the Rhône River,
the Garonne River, and the Alsace plain in 1979 [6]. It was created in 1989 in a
context of insufficient wastewater treatment in the Paris conurbation and new
investment projects in sanitation facilities [7]. Its first achievement consisted in
developing a model, Riverstrahler [8], to dynamically represent the biogeochemical
fluxes of carbon, nitrogen, phosphorus and then silica, for each body of water in the
basin, from headwaters to the Seine outlet, according to constraints such as geomorphology, hydrography, agricultural diffuse sources, and urban discharges. Another
modelling tool, ProSe, was also developed with a transient hydrology on the lower
Seine more dedicated to the Paris conurbation domestic load [9–12]. These tools
have made it possible to bring together research teams on a common object of study,
the entire Seine watershed; the programme has also been a forum for dialogue
between the basin’s institutional partners and researchers, enabling the latter to
make management proposals to establish investment priorities based on the results
of these models [13]. Despite the fact that PIREN programmes have been replaced
by other interdisciplinary programmes, the PIREN-Seine programme has continued
to exist, financially supported by the institutions in charge of the Seine basin
management. Over the past 30 years, it has generated a vast number of publications,
more than 100 PhD theses, hundreds of publications in scientific journals and as
many communications in international workshops and conferences, as well as
Trajectories of the Seine River Basin
3