Teaching hydrology, at undergraduate level, graduate level and in a life-long learning context, has always been a challenge for educators (Nash et al., 1990), and many of the problems still remain (Wagener et al., 2007). Challenging aspects include the heterogeneity of the entities we study and of the students we teach. Students entering hydrology programs come from both engineering and science backgrounds with very different education foci and strengths as well as weaknesses. The educational system that supports the teaching of hydrology must undergo a paradigm shift away from the current practice of imparting a narrow set of basic concepts and a disciplinary set of skills to engineers and scientists with little considerations for the real needs of the area of hydrology, especially when considering the increasing impacts of global environmental change (Wagener et al., 2010). How do we balance the need for hydrology students to have strong disciplinary skills in basic subjects (like maths, physics, soil science) (Kavetski and Clark, 2011), with field and laboratory work (Nash et al., 1990; Kleinhans et al., 2010), while also developing the higher level skills of connecting across disciplines and across places? Given the great complexity of the water problems society faces in a changing world, the teaching of hydrology must adopt a more integrated view of the role of water in the natural and build-environment around us.

These issues call for the teaching of new skill sets, including the ability to read, interpret, and learn from patterns in the landscape; comparative studies to supplement place-based studies; learning through case studies; understanding the time-varying characteristics of hydrological systems, use of space for time substitutions; and modeling of interacting processes such as human-nature interactions and feedbacks. Above all, the new generation of hydrologists must be trained to become both analysts and synthesists. This will inevitably require dissolution of the historical separation between science and engineering in our approach to hydrology education. Teaching methods should be rooted in the scientific and quantitative understanding of hydrologic processes, providing flexible hydrologic problem-solving skills that can evolve if new insights become available, and which can be adapted to provide solutions for new problems and to understand new phenomena. Our hydrology textbooks generally do not contain in-depth treatments of how to predict the hydrologic response after changes in climate, degree in urbanization or land cover have occurred, despite the fact that such predictions will be fundamental for future research and practical hydrological applications. So, how should we teach that, considering that the methods for such prediction are subject to a current scientific debate, and, where is the teaching material coming from?

This special issue aims at addressing these challenges in hydrology education and will include both papers on general issues, such as the hydrological curriculum and professional competences required for the hydrologists of tomorrow, and experiences from concrete teaching approaches. Questions addressed in this special issue on education in hydrology include:

- How do we integrate quantitative and qualitative aspects of hydrology into a holistic approach to hydrology education?
- How does hydrology, and therefore hydrology education, change in a changing world?
- What constitutes a strong hydrology skill set that can evolve to study new phenomena and to solve new problems?
- What are the knowledge gaps we have to fill for teaching hydrology in a changing world?
- How much do hydrologists need to learn about different topics?
- Where do they have to be specialists and where can they be generalists?
- How do we balance place-based versus studies across gradients, numerical rigor versus lab-field experience, problem solving versus scientific inquiry etc.?
- How should field trips be designed for best learning experiences?
- Which new ideas are available for supporting student learning and understanding of hydrological systems? (lab experiments, exercises, …)
- How can continuing education support the life-long learning of hydrologists?
- What set of skills and competencies do hydrologists need to have to be effective in a changing and increasing complex world?
- How can we support the education of hydrologists in less developed countries, which are most vulnerable to environmental change, but who have the least resources for training and capacity building?