Chalk permeability

The Chalk of the United Kingdom and north-west Europe is a major aquifer, relied on in many areas for public water supply. Where groundwater control is required for construction works in or above the chalk, regulators require thorough assessment of the potential impact of these works on water resources. Historically this might have been achieved by interpreting the results of a single well pumping test, but these can be poor at identifying the significant inhomogeneity and anisotropic conditions that often prevail in chalk. These conditions can have a very significant impact on flow rates and groundwater lowering, particularly where mitigation measures, such as partial cut-offs or recharge, are planned. This paper explores a range of alternative strategies that have been used, usually in combination, to quantify the parameters which control inflows and groundwater lowering in the vicinity of construction works which impact on groundwater in the chalk.