The VULCAIN project aims at studying the impacts of climate and socio-economic changes on the hydrosystems exploited for water supply purposes, at short (2020-2040) and middle-term (2040-2060). The study zone is a department of the Languedoc-Roussillon region, south of France, with typical Mediterranean climate, hydrosystems and water management strategies.

Coordinator	Yvan Caballero
CNRM-GAME contact	Eric Martin, Davis Salas y Melia
CNRM-GAME teams	GMME/MOSAYC, GMGEC/ASTER
Project web site	VULCAIN
Funding	ANR
Start date	2006
Duration	4 years

 Goals

The Mediterranean region is subjected to a contrasted climate and an increasing anthropogenic pressure, together with specific interconnected hydro-systems in which groundwater is important. Global warming over Mediterranean regions 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.
Few studies examine the global change impacts on the groundwater resources in the Mediterranean context despite they represent an important part of the available exploited water resources for water supply. Moreover, the principle focus of climate change research regarding to groundwater has been on quantifying the likely direct impacts of changing precipitations and temperature patterns. However, 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 15 years, when alternatively, irrigation systems size should remain constant 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 (2040-2060). The study zone is the Pyrénées Orientales department, 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 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. The hydrosystems vulnerability will be analyzed using hydrological and hydrogeological models developed in previous studies and that will be forced using climatic and socio-economic scenarios. Climatic scenarios will be 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 observed rainfall and temperature chronics. Socio-economic scenarios will be built from a prospective evaluation of the future water demand, based on previous studies at the Languedoc-Roussillon scale (in particular Aqua 2020) and break-point scenarios.
The final project ambition is to develop and integrate the tools and methods needed to operational assessments of the global change impacts, allowing evaluating the future vulnerability of the exploited hydro-systems and of the supplied territory in the Mediterranean context.

The main results expected from this project are:

A) An assessment of the mean and of the spatial and temporal variability of the precipitation and temperature modifications likely to occur for the 2020-2040 and 2040- 60 periods on the study zone using, i) the GCM simulations, ii) the observed trends over the 50 past years, iii) a stochastic generator for precipitations and temperature (necessary for the downscaling from the global GCM scale to the regional scale and for the trend extrapolation). The GCM scenarios will be compared with those based on the extrapolated trends, to look for climate thresholds.

B) Prospective scenarios building methods of the water demand at mean (2020) and longerterm (2040) over a given territory. These methods will allow an integrated spatial assessment of the effects and the uncertainties linked to anthropogenic reaction to climate change, the likely evolution of the European economic situation and the constraints imposed by the environment-protection policies, on the domestic and agricultural water demand evolution of the territory.

C) An assessment of the surface and groundwater hydro-systems vulnerability exploited for their water resource as well as the water dependent territory vulnerability. The hydro-systems vulnerability will be established based on statistical index (mean and critical return-period 4 discharges and piezometric levels, compared to threshold values). The territory vulnerability will be established in comparison to threshold situations over which, the domestic and agricultural water supply will be in danger. In addition to the expected academic results, an operational presentation of the integrated tools and methods needed for a consulting group to perform this kind of assessment at the lower costs will be proposed. It will be addressed to the main water managers of the Languedoc-Roussillon region (Department councils, Regional councils and Basin Water Agency) and will underline the major shortcomings and uncertainties linked to the project results.

 CNRM-GAME contribution

CNRM-GAME is the project expert as regards to the weather, climate scenarios. He participates in the analysis of project results with all partners.

 Partnership

Consortium of 4 partners :

1. BRGM
2. BRL Ingenierie
3. HSM Montpellier
4. CNRM-GAME