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ARS Home » Pacific West Area » Pullman, Washington » Northwest Sustainable Agroecosystems Research » Research » Publications at this Location » Publication #182042
Title: HYDRAULIC AND EROSION TESTS OF A FROZEN SOIL: FACILITY AND EXPERIMENTATION

Author
item GREER, CORY - WASHINGTON ST UNIVERSITY
item WU, JOAN - WASHINGTON ST UNIVERSITY
item McCool, Donald
item HANXUE, QIU - WASHINGTON ST UNIVERSITY

Submitted to: ASAE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 1/2/2005
Publication Date: 7/20/2005
Citation: Greer, C.R., Wu, J.Q., McCool, D.K., Qui, H. 2005. Hydraulic and erosion tests of a frozen soil: facility and experimentation. In: Proceedings of the ASAE Annual International Meeting, July 17-20, 2005, Tampa, Florida. Abstract No. 052013.

Interpretive Summary: Erodibility of soils as impacted by freeze-thaw cycles in the Pacific Northwest is a critical parameter in quantitative soil erosion modeling. The processes of rill generation and soil strength changes, during all phases of freezing and thawing, have not been well understood. Past studies indicate that thawing soils, at soil water content near or exceeding saturation, typically exhibit low strengths and high potential for detachment and transport. A facility for hydraulic and erosion testing of such soils was designed and constructed at the USDA-ARS Palouse Conservation Field Station near Pullman, WA. The facility, consisting mainly of a tilting flume (3 m long by 0.4 m wide) and a radiative cooling system, can effectively freeze the test soil under controlled soil water content to desired depth within a reasonably short time. This paper presents comprehensive design and testing of the facility as well as the results of erosion experiments on a Palouse silt loam soil, which is typical of the Palouse region and is included as a benchmark soil in the USDA’s WEPP (Water Erosion Prediction Project) model. The tests were conducted under fully frozen, fully thawed and partially thawed conditions. Relationships between critical shear stress and erodibility versus soil water content were analyzed and added to the scarce database on freezing and thawing soil.

Technical Abstract: Erodibility of soils as impacted by freeze-thaw cycles in the Pacific Northwest is a critical parameter to the quantification of soil erosion modeling. The processes of rill generation and soil strength changes, during all phases of freezing and thawing, have not been well understood. Past studies indicate that thawing soils, at soil water content near or exceeding saturation, typically exhibit low strengths and high potential for detachment and erosion. A facility for hydraulic and erosion testing of such soils was designed and constructed at the USDA-ARS Palouse Conservation Field Station (PCFS) located near Pullman, WA. The facility, consisting mainly of a tilting flume (3 m long by 0.4 m wide) and a radiative cooling system, can effectively freeze the test soil under controlled soil water content to desired depth within a reasonably short time. This paper presents the comprehensive design and testing of the facility as well as the results of soil erosion experiments on a Palouse silt loam, which is typical of the Palouse region and is included as a benchmark soil in the USDA’s WEPP (Water Erosion Prediction Project) model. The tests were conducted under fully frozen, fully thawed, and partially thawed conditions. The relationships between the critical shear stress and erodibility versus soil water content were analyzed.