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Relationships between physical‐geochemical soil properties and erodibility of streambanks among different physiographic provinces of Tennessee, USA
Author(s) -
Mahalder Badal,
Schwartz John S.,
Palomino Angelica M.,
Zirkle Jon
Publication year - 2018
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.4252
Subject(s) - soil water , soil science , hydrology (agriculture) , erosion , geology , fluvial , shear stress , environmental science , geotechnical engineering , geomorphology , materials science , structural basin , composite material
Erosion of cohesive soils in fluvial environments is dependent on physical, geochemical and biological properties, which govern inter‐particle attraction forces and control detachment rates from stream beds and banks. Most erosion rate models are based on the excess shear stress equation where the soil erodibility coefficient ( k d ) is multiplied by the difference between the boundary hydraulic shear stress ( τ b ) and the soil critical shear stress ( τ c ). Both k d and τ c are a function of soil properties and must be obtained through in situ field or laboratory testing. Many studies have generated predictive relationships for k d and τ c derived from various soil properties. These studies typically were conducted in watersheds within a single physiographic region with a common surficial geology and/or investigated a limited number of soil properties, particularly geochemical properties. With widely reported differences in relationships between τ c and soil properties, this study investigated differences in predictive relationships for τ c among different physiographic provinces in Tennessee, USA. Erodibility parameters were determined in the field using a mini‐jet test device. Among these provinces, statistically four unique clusters were identified from a dataset of 128 observations and these data clusters were used to develop predictive models for τ c to identify dominant properties governing erosion. In these clusters, 16 significant physical and geochemical soil properties were identified for τ c prediction. Among these soil properties, water content and passing #200 sieve (percentage soil less than 75 μm) were the dominant controlling parameters to predict τ c in addition to clay percentage (< 2 μm), bulk density, and soil pore water chemistry. This study suggests that unique relationships exist for physiographic provinces that are likely due to soil physical‐geochemical processes associated with surficial geology that determine minerology of the cohesive soil. Copyright © 2017 John Wiley & Sons, Ltd.