Abstract

Groundwater source protection zones (GPZs) are an integral part of land surface zoning within the Environment Agency’s Policy and Practice for the Protection of Groundwater. The methods and experience gained in delineating GPZs around 1000 groundwater sources in England and Wales are reviewed. The methods include: manual calculations, hydrogeological mapping, analytical and semi- analytical modelling and numerical modelling. The large numbers of sources within a diverse number of hydrogeological settings has led to a structured approach to selecting the GPZ method appropriate to each groundwater source. This includes consideration of the protected yield, data acquisition and formulation of a conceptual flow model. The GPZ methods also include consideration of parameter uncertainty. Further developments in GPZ delineation methods are required to cope with fissured/fractured groundwater flow and to exploit the results of transient groundwater models.