DOI: 10.5066/p9cg3drr
title: Postfire erosion estimates for large California wildfires that occurred between 1984 and 2021

description: This data release presents a compilation of postfire sediment mobilization data from wildfires greater than 100 km2 that occurred in California or regions of southern Oregon that drain to the California coast between 1984 and 2021. This compilation includes three sources of sediment mobilization data: hillslope erosion modeled using the Water Erosion Prediction Project (WEPP) postfire erosion model (Lew and others, 2022 and references therein), field-derived measurements of postfire debris flow volumes, and modeled debris flow volumes produced using the U.S. Geological Survey Emergency Postfire Debris Flow Hazard Assessments (https://landslides.usgs.gov/hazards/postfire_debrisflow/). This dataset supports analysis in Dow and others, 2024.
This data release also includes the materials required to reproduce the WEPP model results, which were run using wepppy, an open-source Python framework for running WEPP (Lew and SrivAnu, 2021). We have included an input file with geographic information on all watersheds such that the results can be reproduced with WEPP. Although every fire should be modeled independently because wepppy requires an individual soil burn severity map as an input, these data should be enough to enable reproduction of all the results in this data release and associated publication. We did not include burn severity maps for all fires as these are publicly available online on the Monitoring Trends in Burn Severity (MTBS) website (https://www.mtbs.gov/). Example wrapper scripts and configuration files are available online (https://github.com/rogerlew/wepppy).

The following items are included in this data release:

A shapefile containing every watershed modeled in WEPP. For each watershed, the associated attribute table contains the fire name, fire date, defining geographic attributes, and WEPP model results.
A shapefile including every fire perimeter in this study. For each fire perimeter, the associated attribute table contains the fire event information from MTBS, the WEPP model results, compiled postfire debris flow results, and total sediment yield.
A group of ten shapefiles containing updated results of the U.S. Geological Survey Emergency Postfire Debris Flow Hazard Assessment for wildfires prior to 2016 (1997–2015), when methods were updated to include revised likelihood (Staley and others, 2017) and volume models (Gartner and others, 2014).
A csv of all watersheds that we modeled with WEPP and the geographic information needed to model them. This table includes the fire name and year associated with each watershed as well as the UTM zone so that each fire can be modeled individually.
A csv containing all postfire debris flow volumes (measured and modeled) and the source for their documentation, location, and volume. 


References
Dow, H.W., East, A.E., Sankey, J.B., Warrick, J.A., Kostelnik, J., Lindsay, D.N., Kean, J.W., 2024, Postfire sediment mobilization and its downstream implications across California, 1984–2021, JGR: Earth Surface. http://doi.org/10.1029/2024JF007725
Gartner, J.E., Cannon, S.H., Santi, P.M., 2014. Empirical models for predicting volumes of sediment deposited by debris flows and sediment-laden floods in the transverse ranges of southern California. Engineering Geology 176, 45–56. https://doi.org/10.1016/j.enggeo.2014.04.008
Lew, R., Dobre, M., Srivastava, A., Brooks, E.S., Elliot, W.J., Robichaud, P.R., Flanagan, D.C., 2022. WEPPcloud: An online watershed-scale hydrologic modeling tool. Part I. Model description. Journal of Hydrology 608, 127603. https://doi.org/10.1016/j.jhydrol.2022.127603
Lew, R., SrivAnu, 2021. rogerlew/wepppy-win-bootstrap: https://doi.org/10.5281/zenodo.4902236
Staley, D.M., Negri, J.A., Kean, J.W., Laber, J.L., Tillery, A.C., Youberg, A.M., 2017. Prediction of spatially explicit rainfall intensity–duration thresholds for post-fire debris-flow generation in the western United States. Geomorphology 278, 149–162. https://doi.org/10.1016/j.geomorph.2016.10.019