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Hydrologic versus geomorphic drivers of trends in flood hazard
Author(s) -
Slater Louise J.,
Singer Michael Bliss,
Kirchner James W.
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2014gl062482
Subject(s) - flood myth , streamflow , hazard , 100 year flood , flooding (psychology) , channel (broadcasting) , flood forecasting , environmental science , floodplain , hydrology (agriculture) , flood insurance , water resource management , geography , geology , drainage basin , computer science , cartography , psychology , computer network , chemistry , geotechnical engineering , archaeology , organic chemistry , psychotherapist
Flooding is a major hazard to lives and infrastructure, but trends in flood hazard are poorly understood. The capacity of river channels to convey flood flows is typically assumed to be stationary, so changes in flood frequency are thought to be driven primarily by trends in streamflow. We have developed new methods for separately quantifying how trends in both streamflow and channel capacity have affected flood frequency at gauging sites across the United States Flood frequency was generally nonstationary, with increasing flood hazard at a statistically significant majority of sites. Changes in flood hazard driven by channel capacity were smaller, but more numerous, than those driven by streamflow. Our results demonstrate that accurately quantifying changes in flood hazard requires accounting separately for trends in both streamflow and channel capacity. They also show that channel capacity trends may have unforeseen consequences for flood management and for estimating flood insurance costs.