Henning is a trained hydrogeologist with more than 30 years of practical experience internationally. In Ireland, Henning has contributed to water resources protection and management initiatives led by the Environmental Protection Agency (EPA) and Geological Survey Ireland (GSI), mainly in the context of the European Union Water Framework and (recast) Drinking Water Directives, and the national legislations that have followed. For public and private sector clients, Henning has also led or contributed to the development of public and private groundwater supplies, the establishment and operations of monitoring networks and programmes, the environmental impact assessment of landfills, legacy waste, and contaminated land sites, and the technical review of effluent discharges. Based on his experiences and skillsets, Henning has contributed to EPA technical guidance for the authorisation of effluent discharges to ground, the investigative assessments of rural and urban catchments, the evaluation of streamflow depletion (resulting from groundwater abstractions), and the implementation of the updated (2024) drinking water regulations.