Long-Term Monthly Baseflow Index Signatures

This resource presents data used in the study by van der Heijden et al. (under review, 2025). The data contains monthly mean baseflow indices (BFI) for 1,432 United Stated Geological Survey (USGS) streamflow gages across the Continental United States (CONUS).

The streamflow gages used are those considered of reference-quality by the Geospatial Attributes of Gages for Evaluating Streamflow, version II (GAGES-II) dataset (Falcone, 2011) that contain at least 20 years of continuous daily streamflow measurements.

Baseflow separation was conducted using a single parameter recursive digital low-pass filter based on Lyne and Hollick, (1979) for baseflow separation. The filter, implemented in the R package EcoHydRology (Fuka et al., 2014), was converted to Python (Hamshaw et al., 2020) and as part of this research is now available through the Baseflow Python package developed by Brigham Young University Hydroinformatics group (https://github.com/BYU-Hydroinformatics). The filter parameter was tuned to the long-term flow history of each gage individually using the 10th non-exceedance percentile of streamflow.

References:
Ryan van der Heijden, Ali Dadkhah, Scott Hamshaw, Mandar Dewoolkar, Ehsan Ghazanfari, Norm Jones, Gustavious Williams, Prabhakar Clement, Donna M. Rizzo. “Identifying and interpreting physical processes and NWM prediction bias associated with baseflow regimes across the CONUS.” Water Resources Research (under review, 2025).

Falcone, James A. 2011. “GAGES-II: Geospatial Attributes of Gages for Evaluating Streamflow.” Report. Reston, VA. USGS Publications Warehouse. https://doi.org/10.3133/70046617.

Lyne, V. D. and Hollick, M.: Stochastic time-variable rainfall runoff modelling, Hydrology and Water Resources Symposium, Institution of Engineers, Australia, Perth, 10–12 September 1979, 89–92, 1979.

Hamshaw, Scott D., Donna M. Rizzo, Ali Javed, and Linh Nguyen. "Watershed data science at the event scale: Revealing insights in watershed function through analysis of concentration-discharge relationships." In AGU Fall Meeting Abstracts, vol. 2020, pp. H077-08. 2020.

Fuka DR, Walter MT, Archibald JA, Steenhuis, TS, and Easton ZM. “EcoHydRology, a community modeling foundation for Eco-Hydrology.” 2014.