Methodological framework for delineating wellhead protection areas for groundwater abstraction wells

Groundwater is a strategic resource whose protection is essential to maintain its quality and prevent contamination processes. Delineating protection perimeters around abstraction points makes it possible to establish zones where potentially polluting activities are restricted, thereby reducing risk to the resource and supporting planning and the sustainable management of water supply.

In this work, the main approaches for determining protection perimeters are analysed and an operational methodology, implemented in a spreadsheet, is proposed to facilitate its application in environmental assessment and management contexts, taking into account the available hydrogeological data. The approach is developed and applied in the province of Valencia, with an emphasis on consistency between the regulatory framework and the definition of protection zones based on groundwater travel times.

The reference framework is established through a review of the applicable European and Spanish legislation for the protection of abstraction points, from the EU Water Framework Directive to basin-specific regulations, enabling the definition of the required zones, the criteria associated with travel times, and the activities subject to restrictions. Building on this basis, both analytical and numerical delineation approaches are examined: the former provide rapid solutions but rely on restrictive assumptions (homogeneous and isotropic media), whereas the latter are based on mathematical models (e.g., MODFLOW) capable of representing pumping-induced flow and estimating travel-time isochrones.

As a result, a replicable and transparent spreadsheet-based procedure is presented, integrating regulatory criteria and hydrogeological principles to support the delineation of protection zones, contributing to more traceable decision-making in contamination prevention and the sustainable management of groundwater resources.