Development of cooperation on managing transboundary groundwaters in the pan-European region: The role of international frameworks and joint assessments

•Knowledge of transboundary aquifers (TBAs) has evolved through assessments carried out under the Water Convention.•Inventories, international institutional frameworks, guidelines and projects support formal TBA cooperation.•Sound conceptual hydrogeological models of TBAs are needed.•Joint assessment of shared aquifers needs broadening to better foster cooperation.•Dialogues linking technical groundwater information to management improve impact. pan-Europe, from Western Europe to Central Asia. Knowledge of transboundary aquifers (TBAs) in the pan-European region has evolved through an inventory under the Convention on the Protection and Use of Transboundary Watercourses and International Lakes (Water Convention) completed in 1999, and the First and Second Assessments of transboundary waters undertaken in 2007 and 2011. These “snapshots”, together with intergovernmental review processes indicate significant advances in the recognition of TBAs. Reference is made to where collaboration on transboundary groundwaters has developed, demonstrated by cooperation arrangements and joint projects. The findings highlight a number of factors; inventories, participation in the work of the Water Convention and application of guidelines, joint projects, the legal and institutional framework for management and the role of EU legislation. There is a need for sound conceptual hydrogeological models of TBAs, but also for broadening joint assessment to better foster cooperation. Bringing together in transboundary dialogues technical information with an understanding of the demands for groundwater and related drivers as well as better understanding of the human, social and institutional dimensions of managing TBAs can add to their effectiveness. Such approaches can better provide for defining and discussing policy responses and for mobilising resources and the necessary political support.