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Causal effect of impervious cover on annual flood magnitude for the United States

March 5, 2020

Despite consensus that impervious surfaces increase flooding, the magnitude of the increase remains uncertain. This uncertainty largely stems from the challenge of isolating the effect of changes in impervious cover separate from other factors that also affect flooding. To control for these factors, prior study designs rely on either temporal or spatial variation in impervious cover. We leverage both temporal and spatial variation in a panel data regression design to isolate the effect of impervious cover on floods. With 39 years of data from 280 U.S. streamgages, we estimate that a one percentage point increase in impervious basin cover causes a 3.3% increase in annual flood magnitude (95%CI: 1.9%, 4.7%) on average. Using 2,109 streamgages, some of which have upstream regulation and/or overlapping basins, we estimate a larger effect: 4.6% (CI: 3.5%, 5.6%). The approach introduced here can be extended to estimate the causal effects of other drivers of hydrologic change.

Publication Year 2020
Title Causal effect of impervious cover on annual flood magnitude for the United States
DOI 10.1029/2019GL086480
Authors Annalise G. Blum, Paul J. Ferraro, Stacey A. Archfield, Karen R. Ryberg
Publication Type Article
Publication Subtype Journal Article
Series Title Geophysical Research Letters
Index ID 70217011
Record Source USGS Publications Warehouse
USGS Organization WMA - Integrated Modeling and Prediction Division
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