Web applications that share level-12 HUC data and models of the CONUS

HydroTerre web applications and services provide the Essential Terrestrial Variable (ETV) datasets to create common hydrological models anywhere in the continental United States (CONUS). This service allows web users to download data for their own purposes in their own computing environment. The datasets are provided using standard Geographic Information System formats and the data transformation is dependent on the users own needs, goals, and computing environment. In this article, we demonstrate three web applications and web services that share data and models with users via web interfaces, which automate the data-transformations for United States Geological Survey level-12 Hydrological Unit Codes (HUC-12) in order to be consumed in hydrological models. Penn State Integrated Hydrological Model (PIHM) is demonstrated here, but the workflows serve as a template for other models to adapt and become new services. The emphasis of this article is to demonstrate the feasibility of sharing both model input and output data via web interfaces that capture users' provenance. Capturing provenance serves as a new data resource to share amongst modelers, which we believe will improve modeling reproducibility and shift the focus from data preparation to data analysis. We want to demonstrate that workflows empower modelers to create hydrological models rapidly anywhere in the CONUS and the interface to do so is a critical part of the process. To explain the interface, an explanation of both hardware and software architecture is required, as the way they are coupled is critical for performance and constrain the interfaces that execute workflows in a distributed computing environment.