Présentations Colloques

Local communities experiencing land use changes may be concerned about the sustainability of their water resources and request local governments to explain their decisions on groundwater allocation. However, local governments often have to make these decisions based on limited hydrogeological information because limited funding resources prohibit extensive hydrogeological studies. Often, the only source of information on aquifers and groundwater availabilities are investigation reports submitted to support water take consent applications. These investigations may be biased or may be restricted to a relatively small area of interest, while the aquifer in question extends over a much larger area. A major challenge for local governments is therefore evaluating the reliability of this kind of information, and communicating to the community how this information is used in decision making. **This paper presents a case study from the Auckland region in New Zealand, where land use is currently changing from dairy farming to avocado growing. The dairy farming community raised concerns about the increased groundwater demand and asked for clarification by the local government. Hydrogeological information was available only from investigations supporting the avocado growers’ consent applications. At the example of this case study, we discuss (1) different interpretations of hydrogeological information depending on different points of view, (2) the level of understanding of hydrogeological information by the community, (3) perceptions of the community regarding uncertainty, contradiction or bias of the presented information, and (4) whether or not this kind of information is legitimate for local governments.**