years of eWaterCycle: from prototype-forecast to platform for Open and FAIR hydrology
Authors: Hut Rolf , Drost Niels , van de Giesen Nick , Kalverla Peter , Verhoeven Stefan , Schilperoort Bart , Aerts Jerom 
Published: March 2024

Over the last decade our answer to the question: &#8220;but what is eWaterCycle?&#8221; has changed considerably. In 2014 we presented the first iteration of eWaterCycle: we showed that it was feasible to build a real time hydrological forecasting system that ran an ensemble of global models, forced with weather forecasts, assimilating satellite observations at every timestep, all from pre-existing openly available components.In the light of the discussion in the hydrological community on reproducible science [Hutton, 2016] we build the next iteration of eWaterCycle: a platform that allows everyone to use commonly available hydrological models. Years (and a pandemic) later this platform is now openly available [Hut, 2022]. The vision behind the platform is to take as much as possible the computer-related headaches of running other people&#8217;s models away to let hydrologists focus on the hydrology. Furthermore, eWaterCycle is &#8216;FAIR by Design&#8217;: it should be easy to make any analysis done by eWaterCycle adhere to the FAIR principals. Using eWaterCycle MSc students have been able to do the type of research that previously was done by a PhD and PhDs have done the type of research that previously would require a whole team of people. Large Sample hydrology studies, Model coupling and climate change impact studies have all been done using eWaterCycle.Adding one&#8217;s own model to the platform, however, still required considerable effort which limited the uptake by the broader hydrological community. That&#8217;s why recently we released v2.0 of eWaterCycle which fixes this: it is now significantly easier to add models to eWaterCycle!Looking forward, among other things we will be:Making teaching material on hydrological modelling available as Open Educational Resources through eWaterCycle [funded project]
Adding data assimilation as a module to eWaterCycle [funded project]
Add easy access to Large Sample Hydrology datasets (camels / caravan) [looking for students]
Study the impact of climate change on all catchments of the world, using many different hydrological models [looking for students]
Connect or host eWaterCycle on the infrastructure currently being developed for Destination Earth (DestinE) [looking for funds and collaborations]
In this presentation I will reflect on the achievements of the last decade, highlight the scientific results generated with eWaterCycle and look forward to the next decade.&#160;Hutton,&#160;C.,&#160;T. Wagener,&#160;J. Freer,&#160;D. Han,&#160;C. Duffy, and&#160;B. Arheimer&#160;(2016),&#160;Most computational hydrology is not reproducible, so is it really science?,&#160;Water Resour. Res.,&#160;52,&#160;7548&#8211;7555, doi:10.1002/2016WR019285.Hut, R., Drost, N., van de Giesen, N., van Werkhoven, B., Abdollahi, B., Aerts, J., Albers, T., Alidoost, F., Andela, B., Camphuijsen, J., Dzigan, Y., van Haren, R., Hutton, E., Kalverla, P., van Meersbergen, M., van den Oord, G., Pelupessy, I., Smeets, S., Verhoeven, S., de Vos, M., and Weel, B.: The eWaterCycle platform for open and FAIR hydrological collaboration, Geosci. Model Dev., 15, 5371&#8211;5390, https://doi.org/10.5194/gmd-15-5371-2022, 2022.