Skip to main content
ARS Home » Plains Area » El Reno, Oklahoma » Oklahoma and Central Plains Agricultural Research Center » Agroclimate and Hydraulics Research Unit » Research » Publications at this Location » Publication #425171
Research Project: Development of a Monitoring Network, Engineering Tools, and Guidelines for the Design, Analysis, and Rehabilitation of Embankment Dams, Hydraulic Structures, and Channels

Location: Agroclimate and Hydraulics Research Unit

Title: A conceptual framework for erosion of unsaturated cohesive soil

Author
item Livsey, Daniel
item Heiner, Bryan
item Hunt, Sherry
item Searles, Cassidy

Submitted to: Water Resources Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/24/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Soil loss due to erosion costs the United States economy more than $20 billion annually from reduced agricultural productivity, flooding from dam and levee failures, and reduced water storage in reservoirs. To date, accurate prediction and modelling of soil loss and erosion remains difficult and relies on labor-intensive site-specific measurements. This study identifies low-cost measurements that can accurately predict soil erodibility and provides a physical framework from which soil erodibility can be predicted. Changes in soil moisture alone induced changes in soil erodibility by 1000-fold. The proposed framework promises to provide more cost-effective estimates of soil erosion across landscapes and may aid efforts aiming to reduce soil loss. USDA is an equal opportunity provider and employer.

Technical Abstract: Accurately predicting soil erosion remains difficult owing to variability in the factors that drive the interaction of unsaturated flow and soil deformation. For example, seasonal changes in soil moisture affect infiltration, swelling, and soil stiffness, all factors that interact and may affect soil erosion through changes in matric suction, strain, and shear strength. In this study, the effect of changing soil moisture on soil detachment rate and critical shear stress was investigated using erosion tests conducted on statically compacted lean (n = 7) and fat (n = 7) clay samples with constant bulk density and degree of saturation ranging from 9% to 98%. Soil detachment rate decreased with increasing soil moisture from 123 to 0.2 cm3/(N-s) and 122 to 0.3 cm3/(N-s) for the lean and fat clay, respectively. Conversely, critical shear stress increased with soil moisture from 0.4 Pa to 3.5 Pa and 0.4 Pa to 6.1 Pa for the lean and fat clay, respectively. A conceptual framework that links unsaturated cohesive soil erosion to infiltration and soil swelling is utilized to develop regressions for the prediction of the soil detachment rate (R2 = 0.90, p-value < 6e-7) and critical shear stress (R2 = 0.80, p-value < 6e-5) from readily obtained measurements of infiltration, swelling, bulk density, shear strength, and moisture content. Implications for predicting soil erosion across landscapes and earthen structures (e.g., earthen dams and levee) are discussed.