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Regional Variation in Gravel Riverbed Mobility, Controlled by Hydrologic Regime and Sediment Supply
Author(s) -
Pfeiffer Allison M.,
Finnegan Noah J.
Publication year - 2018
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 - 10.1002/2017gl076747
Subject(s) - bed load , sediment , hydrology (agriculture) , flood myth , sediment transport , intermittency , environmental science , bedform , magnitude (astronomy) , geology , geomorphology , geography , meteorology , geotechnical engineering , physics , archaeology , astronomy , turbulence
The frequency and intensity of riverbed mobility are of paramount importance to the inhabitants of river ecosystems as well as to the evolution of bed surface structure. Because sediment supply varies by orders of magnitude across North America, the intensity of bedload transport varies by over an order of magnitude. Climate also varies widely across the continent, yielding a range of flood timing, duration, and intermittency. Together, the differences in sediment supply and hydroclimate result in diverse regimes of bed surface stability. To quantitatively characterize this regional variation, we calculate multidecadal time series of estimated bed surface mobility for 29 rivers using sediment transport equations. We use these data to compare predicted bed mobility between rivers and regions. There are statistically significant regional differences in the (a) exceedance probability of bed‐mobilizing flows ( W * > 0.002), (b) maximum bed mobility, and (c) number of discrete bed‐mobilizing events in a year.