Schlumberger Water Services has completed a major groundwater modelling project, involving conceptual and numerical modelling of the North Kent Chalk and the overlying Palaeogene aquifers. The project was commissioned by the Environment Agency, the leading public body responsible for managing and ensuring proper use of groundwater in England and Wales. Groundwater in North Kent is heavily utilised for both public supply and industrial purposes, and it is also likely to be an important element in the hydroecology of the North Kent Marshes which form a part of the Swale Special Protection Area, an internationally recognised wildlife conservation area.

The specific objectives of the project related to a number of important management decisions which needed to be made in relation to groundwater-related legislation and policy, such as the review of groundwater abstraction consents under the Habitats Regulations and groundwater resource assessment under the Catchment Abstraction Management Strategy (CAMS) procedures.

To fulfil the primary objective, the Environment Agency requested that two groundwater impact assessment model runs were completed on the final calibrated model. These were a ‘no groundwater abstraction’ model run, where all groundwater abstractions were removed; and a ‘full licensed groundwater abstraction’ model run where all licences were run at their maximum licensed rate. It was found that some groundwater abstraction ‘well’ cells were going dry during the ‘full licensed’ simulation.  An innovative modelling approach, using composite boundary conditions, which allowed the abstractions to abstract the maximum possible amount of water, was implemented to avoid this problem.

It was found that the results from these two models fulfilled the requirements of the project objectives, and therefore no further impact assessment runs were requested. The results of the modelling will be combined with the results of hydrochemical, ecological and geomorphological surveys as part of the North Kent Marshes Sustainability Study.