A comprehensive calibration framework for the Northwest River Forecast Center

Geoffrey Walters, Cameron Bracken , Bradley Gilles, Leah Pope, Sonali Choski, Victor Stegemiller, Julie Bracken, Stephen King, Taylor Dixon, Joe Intermill

In this paper we present a comprehensive framework developed by the Northwest River Forecast Center (NWRFC) for calibration of arbitrary hydrologic basins. The framework includes hydrology, snow, routing, channel loss, and consumptive use models. Data inputs include a wide range of open access datasets for land use, land cover, and meteorology. The framework can handle basins with diverse hydrologic conditions, including permanently glaciated regions. We also develop a flexible automatic calibration system which can handle numerous unobservable model parameters in a computationally efficient manner such that calibrations can be run on a modern laptop in under 10 minutes. The framework presents a new standard for the quality of calibrations that are possible with lumped conceptual hydrologic models with careful data curation and an objective calibration framework combined with expert local knowledge (human in the loop). In addition we have made wrapper packages available for the entire suite of NSWRFS models including SAC-SMA, SNOW17, and Lagk. We hope these modern interfaces will increase the accessibility of these models and facilitate future research.