Author
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McCool, Donald |
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Submitted to: Encyclopedia of Soil Science
Publication Type: Monograph Publication Acceptance Date: 8/8/2001 Publication Date: 12/30/2002 Citation: Mccool, D.K. 2002. Erosion, snowmelt. Encyclopedia of Soil Science. Interpretive Summary: In many areas of the world, winter hydrology is the primary cause of soil erosion. In this paper, we discuss winter processes including conditions from those where the soil freezes and thaws almost diurnally and is subjected mainly to rainfall, to those where the soil remains frozen for several months, precipitation occurs in other solid form during all or part of the winter season, and erosion occurs during a period of spring snowmelt. Some areas, such as the Palouse region of eastern Washington, northern Idaho and northeastern Oregon, are subjected to several runoff and erosion events each winter because the winter temperatures and precipitation patterns lead to multiple soil freezing and thawing occurrences with accompanying rain or snowmelt events. Most measures to prevent erosion damages from winter processes are similar to those for other seasons. Crop and rangeland is best protected by vegetal and surface cover. Surface cover protects from splash detachment, insulates the soil, and slows runoff. Snow collected in standing residue can prevent soil freezing and the creation of an impermeably frozen condition. No-till practices produce root and other pores that enable infiltration when the soil is frozen. Likewise, deep ripping, chiseling, or slot mulching below expected frost depth can prevent formation of a continuous frost layer and lead to increased infiltration. Technical Abstract: In many areas of the world, winter hydrology is an important part of the annual erosion process; in some regions it is the primary cause of erosion. In this paper, we discuss winter processes including conditions from those where the soil freezes and thaws almost diurnally and is subjected mainly to rainfall, to those where the soil remains frozen or is snow-covered for several months, precipitation occurs as snow or in other solid form during all or part of the winter season, and erosion occurs during a period of spring snowmelt. Some areas, such as the Palouse region of eastern Washington, northern Idaho and northeastern Oregon, are subjected to several runoff and erosion events each winter because the winter temperatures and precipitation patterns lead to multiple soil freezing and thawing occurrences with accompanying rain or snowmelt events. Most measures to prevent erosion damages from winter processes are similar to those for other seasons. Crop and rangeland is best protected by vegetal and surface cover. Surface cover protects from splash detachment, insulates the soil, and slows runoff. Snow collected in standing residue can prevent soil freezing and the creation of an impermeably frozen condition. No-till practices produce root and other pores that enable infiltration when the soil is frozen. Likewise, deep ripping, chiseling, or slot mulching below expected frost depth can prevent formation of a continuous frost layer and lead to increased infiltration. |
