Using hydrogeological data to characterize regional Chalk flow processes in East Kent

The Chalk of southern England is known to be a dual porosity - dual permeability porous medium, with a very low permeability and high porosity matrix. It has a fracture system providing the transmissivity and a low unconfined storage coefficient of up to 2%. Conceptualization of regional aquifers is carried out to support regional modelling studies. In such studies, observation well piezometry is of primary importance in understanding the hydrogeology of an area. While flow gauging provides an understanding of surface water responses, observation wells provide spatial detail of the groundwater response within each catchment. During review of the Environment Agency's East Kent Chalk groundwater model, geomorphological and hydrogeological data were used to characterize the area in two zones; the primary and secondary dip slopes, in the first part of this paper. The second part of the paper considers quality control and classification of the piezometry responses with respect to permanent and ephemeral Chalk streams and the Chalk escarpment. The third part of the paper looks at an analysis of lag between rainfall and recharge to the water table. This analysis can help to understand processes in the unsaturated zone and aid their incorporation into groundwater models.