Programme OS3f Regional and nationwide
Vulnerability of Mediterranean hydrosystems to climate changes and
human activities: the VULCAIN project
Author(s): Assessing spatial and temporal mean variability of likely future
precipitation and temperature modifications for the 2020-2040 and 2040-60 periods over a Mediterranean basin
Author(s): Yvan Caballero, Luc Neppel, Bernard Ladouche, Jean-Louis Pinault, David Salas, Melia Salas, Eric Martin,
Nathalie Dorfliger, Jean-Daniel Rinaudo, Jean-Michel Citeau, Sébastien Chazot, Laure Maton, Keltoum Chaouche,
Isabelle Terrasson, Perrine Fleu
Yvan Caballero(1)(*), Luc Neppel (3), Bernard Ladouche (1), Jean-Louis
Pinault (2), David Salas y Melia (5), Eric Martin (5), Nathalie Dorfliger (1), Jean-Daniel Rinaudo (1), Jean-Michel
Citeau (4), Sébastien Chazot(4), Laure Maton (1), Keltoum Chaouche (3), Isabelle Terrasson (4), Perrine Fleury
(*) corresponding author
(1) BRGM - Unité EAU-RMD. Service Géologique Régional Languedoc
– Roussillon. 1039, rue de Pinville.
(2) BRGM – Unité EAU-M2H. Centre Scientifique et
Technique. B.P. 6009. 45060 Orléans Cedex 02.
(3) HydroSciences Montpellier – HSM. Maison des Sciences
de l’Eau, Université Montpellier II. Place Eugène
Bataillon. 34095 Montpellier Cedex 5.
(4) BRL ingénierie.
1105, Avenue Pierre Mendès France. BP 4001. 30001 Nîmes Cedex.
(5) Groupe d’étude de l’atmosphère
météorologique. CNRM-GAME (Météo-France, CNRS). 42 Avenue de
Coriolis. 31057 Toulouse.
Keyword(s): Climate change, GCM, downscaling,
observed trends, climate scenarios, hydrological and hydrogeological modelling, Mediterranean
Session: OS3f Regional and nationwide
The Mediterranean region, that includes interconnected hydro-systems in which groundwater is important, is
subjected to a contrasted climate and an increasing anthropogenic pressure.
Global warming over
Mediterranean region will probably cause more warm and dry summers and more precipitation during warmer
winters despite shorter rainy seasons. Those changes are likely to exaggerate considerably the range in flows
between winter and summer. They will also complicate the water management strategies mainly oriented to respond
to the domestic and agricultural water demand.
In the Languedoc-Roussillon region for instance, the population
growth (on a mean range of 1,5% per year) is likely to provoke a substantial increase of the water demand by a rate
close to 20% in the next 15 years, when alternatively, irrigation systems size should slightly decrease in the future. In
addition, environment-protection policies will be enhanced in the future with the implementation of the European
Water Framework directive.
Within this general framework, the VULCAIN project aims for the
implementation of an integrated (transdisciplinary) modelling method to assess the climatic and socio-economic
driving forces impacts over the Mediterranean hydro-systems at mean (2020-2040) and longer- term (2040-
The study zone is the Pyrénées Orientales département, chosen because it contains on the one hand,
specific Mediterranean hydro-systems (coastal multi-layer aquifer, karstic systems with endogenous and exogenous
recharge by rainfall and water losses and three river basins controlled by dams), and on the other hand, a socio-
economic context that is close to the most critical of the Languedoc-Roussillon region in terms of water demand and
available water resources.
This paper presents the first-year results of the VULCAIN project. Climate
scenarios were built both from the simulation results of six global circulation models (GCM) (four of which involved
in the IPCC-AR4 project) under the A2 greenhouse gases emission scenario of the IPCC and from trends provided
by stationarity analysis on the observed rainfall and temperature chronics during past 50 years. A precipitation and
temperature stochastic generator was used to the downscaling and for the observed trend extrapolation. A baseline
scenario was developed, describing the expected evolution of economic activities depending on the water resources
and on socio-economic and political drivers of the study area. Assuming that climate does not change, this scenario
was built to be consistent with assumptions underlying the definition of the SRES scenarios at a global level. Together
with the climate scenarios, it will be used to force hydrological/hydrogeological models developed in previous
studies. Early results of the integration between water use and management (linked to the socio-economic context)
and hydrological/hydrogéological models are presented. Aiming to develop integrated tools and methods to the
operational assessment of the global change impacts, they will allow evaluating the future vulnerability of the exploited
hydro-systems and of the supplied territory in the Mediterranean context.