CLIMAWAT

CLIMAWAT was a three-year research project funded by the EU-RDF INTERREG IVA France (Channel) - England programme. It was a joint research project between the University of Brighton, the University of East Anglia, the Université de Brest, the Université de Rennes and the Centre National de la Recherche Scientifique (CNRS). The project team were also guided by an industrial advisory group including Southern Water, South East Water, the Environment Agency and ChalkRock Limited.

This research helped to develop a better understanding of the percolation mechanisms from the unsaturated to saturated zones and will determine suitable locations for artificial groundwater recharge, including the percolation mechanisms, the storage capacity and the period of time that injected water could be available for use.

The CLIMAWAT project objectives were to address the impacts of changing climate (in particular rainfall) on the amount and quality of rainwater recharge to major fractured rock aquifers in chalk and granite catchments. In addition, we investigated the effect of changes of the amount of water entering a groundwater system on the distribution and impacts of contaminants (nitrates and pesticides). The project had the support of regulatory authorities and water management companies, and helped to define future aquifer management policy and address several issues under the Water Framework Directive (2000/60/EC).

The two catchments investigated were the Patcham catchment, Brighton, UK (previously used as a part of the FLOOD1 project), and the Ploemeur Catchment, Brittany, France. The two experimental fields located in Brighton and Rennes were studied in the context of their pedologic and hydrogeologic properties with tensiometers and piezometers in order to monitor the recharge to the chalk and granite aquifers.

Alongside the physical modelling of recharge, geochemical techniques - including noble gas chemistry and stable isotopes - were used to trace recharge pathways and to estimate water residence times in the saturated and unsaturated zones. The detailed 3-D geophysical (electromagnetic) survey at different periods of time at both sites provided the electrical resistivity 3-D models which were compared to the geological and hydrogeological properties obtained at these sites in order to improve the calibration of the electrical to hydrological model conversion for the time-dependent parameters studies.

This involved staff from East Anglia, Brighton, Bretagne Occidentale and Rennes, allowing cross checks between laboratory results and a combined approach using different techniques to be applied to both study sites.