Quantifying the sources, flowpaths and transit times of water at the catchment scale is a grand challenge in hydrology. Until recently, progress has been hampered by technological limitations. However, recently new instruments have been introduced to the market that can measure various parameters at unprecedented temporal resolutions – providing new vistas on the complex rainfall-runoff transformation processes. Together with Prof. Jeffrey J. McDonnell (University of Saskatchewan, Canada), LIST’s Catchment and Eco-hydrology (CAT) research group has been at the forefront of these new approaches for tracing rapid surface water flowpaths (with terrestrial diatoms), mapping saturated area dynamics (via thermal IR imagery), investigating isotopic signatures of water in soils (through testing different water extraction methods), or measuring high frequency variability of isotopic signatures in stream water and precipitation (via a newly designed portable mass spectrometer).Here, we propose to expand the range of collaborative activities between our groups and take these to the next level – leveraging past investments into innovative research avenues in hydrological sciences and thereby creating new opportunities for research projects, publications and market solutions.With LIST’s orientation towards a Research and Technology Organisation, the collaborative framework offered by the Mobility In funding scheme will allow to pursue a dual strategy of: (i) continuity in exploring innovative technological solutions for overcoming currently prevailing knowledge gaps in hydrological processes research and (ii) introduction of LIST solutions and products into international markets and hydrology and eco-engineering applications. For this Mobility In proposal, we can build on our on-going research into biological tracers [FNR CORE ECSTREAM], thermal IR imagery [FP7 ITN INTERFACES], soil water – plant interaction [FNR CORE SOWAT] and the development of a portable mass spectrometer [FNR PoC FIELDSPEC]. Our work will also leverage Prof. McDonnell’s work with Los Gatos Inc. in developing a high-frequency laser spectrometer for water isotope composition. Our joint research will rely on his work published in Nature Geosciences in 2010 and paper in review now in Nature showing evidence of eco-hydrological separation. Furthermore, we will take advantages of Prof. McDonnell’s research connections in China to extend and internationalize LIST research where we can build on our fundamental work in Luxembourg for application in China’s Loess Plateau—one of the most degraded regions of the world. Similarly, we will also build new joint research programmes linked on the new Good Year cold room facility in Luxembourg, where the cold regions research of McDonnell’s group in Canada will provide immediate experience upon which to base our new LIST-based cold room work.Research activities foreseen in this Mobility In proposal will be organised around four main work packages:WP1: High-frequency signatures of O and H stable isotopes in waterWP2: Towards a concept of “soil water functional pools”WP3: Hydrological processes research within the Good Year cold room facilityWP4: The Loess eco-restauration project in ChinaBeyond the specific objectives of these individual work packages (e.g. publications, proof-of-concept work, prototype testing), we expect this collaboration to trigger new opportunities for projects in experimental hydrology and new international collaborations. Moreover, Prof. McDonnell will be able to substantially contribute to the construction of a sustainable framework for doctoral and post-doctoral research in hydrological sciences at LIST – also in the light of the forthcoming call for proposals on Doctoral Training Units in the FNR PRIDE programme.