This project enables community research by facilitating collaborative and reproducible hydrologic science that advances hydrologic understanding through scalable integration of data and models from many sources. The XSEDE resources requested in this proposal will be used to host HydroShare-JupyterHub, a science gateway application that is part of the HydroShare Hydrologic Information System operated by the Consortium of Universities for the Advancement of Hydrologic Science Inc. (CUAHSI). HydroShare includes a domain-specific data and model repository established to advance hydrologic science by enabling individual researchers to easily share products resulting from their research, not just the scientific publication summarizing a study, but also the data, models and workflow scripts used to create the scientific publication and reproduce the results therein. HydroShare is comprised of two sets of functionality: (1) a repository for users to share and publish data and models, collectively referred to as resources, in a variety of formats, and (2) compute tools (gateway apps) that can act on content in HydroShare and support web-based access to compute capability. Together these serve as a platform for collaboration and computation that integrates data storage, organization, discovery, analysis and computation, and that allows researchers to employ services beyond the desktop to make data storage and manipulation more reliable and scalable, while improving their ability to collaborate and reproduce results. HydroShare-JupyterHub leverages CyberGIS-Jupyter (a novel geospatial information system and science framework for integrating cyberinfrastructure and Jupyter Notebook capabilities to achieve reproducible and scalable geospatial analytics) to provide access to state of the art models and HPC resources for advancing understanding in hydrology. Two models serve as driving use cases. The Structure for Unifying Multiple Modeling Alternatives (SUMMA) model enables structured and systematic model process intercomparisons and alternative hypothesis testing. The gateway makes this latest thinking in advancing hydrologic modeling accessible to a broad community of Earth science researchers, thereby transforming research practices and the knowledge generated from this research. The WRF-Hydro modeling framework is used by the National Water Model (NWM). The gateway will provide access to WRF-Hydro configured identically to the NWM to run on subset study areas to support research to advance NWM capabilities and the use of NWM in modeling research.