8. Well Head Protection Areas

In the previous chapter, methods for the assessment of the vulnerability of aquifers to contamination are illustrated as a first step towards the protection of groundwater resources. Here, static and dynamic protection measures of sources of water for human consumption are presented. Static protection entails the definition of areas of land around the water source that must be subjected to specific safeguard measures and land use limitations. Such areas can be defined via geometric methods (i.e., defining the area arbitrarily, such as by drawing a circle of set radius around the pumping well) or via the time of travel approach. The latter method takes into account the aquifer type and its hydrodynamic parameters, in particular using the groundwater flow velocity to delineate protection areas defined by the time it takes a contaminant to reach the drinking water extraction well. Dynamic protection entails the establishment of a monitoring network along the perimeter of previously defined protection areas. Practical guidance is provided for appropriately designing this network in terms of monitoring-well positioning and sampling frequency.