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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Watershed Physical Processes Research » Research » Publications at this Location » Publication #186458
Title: IMPACT OF NON-ERODIBLE LAYER ON EPHEMERAL GULLY DEVELOPMENT

Author
item Wells, Robert - Rob
item GORDON, LEE - SUNY AT BUFFALO
item BENNETT, SEAN - SUNY AT BUFFALO
item Alonso, Carlos

Submitted to: Federal Interagency Sedimentation Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/4/2006
Publication Date: 4/4/2006
Citation: Wells, R.R., Gordon, L., Bennett, S.J., Alonso, C.V. 2006. Impact of non-erodible layer on ephemeral gully development. In: Proceedings of the 8th Federal Interagency Sedimentation Conference, April 2-6, 2006, Reno, Nevada. CDROM.

Interpretive Summary: Laboratory experiments were conducted to examine the impact of a non-erodible layer on ephemeral gully initiation, development, and migration. In many areas of the U.S., especially the southeastern U.S., below the soil surface a layer may be present with characteristics that make it more resistant to erosion. These layers are typically referred to as plowpan or fragipan layers. As erosive flows cut into top soils, they erode the soil down to the non-erodible layer and then expand laterally. The current experiments do not allow for widening but give an indication on the expected migration rates and sediment yield expected from this type of erosional condition.

Technical Abstract: As headcut erosion accelerates, the formation of ephemeral gullies can significantly increase the loss of topsoil and decrease the productivity of agricultural lands. Ephemeral gullies are erosional features, usually larger than rills, caused by concentrated flow that may be erased by normal tillage practices. Most researchers agree that a critical or threshold level of concentrated flow is required to initiate ephemeral gullies and once initiated, there is positive feedback between flow and erosion. The location and size of ephemeral gullies is controlled by the generation of concentrated surface erosion of sufficient magnitude and duration to initiate and sustain erosion for a particular soil. Once formed, ephemeral gullies tend to rejuvenate near or in the same location from year to year. Experiments were conducted to examine the effect of a non-erodible layer on growth, development, and upstream migration of headcuts typical in ephemeral gullies. During migration, the depth of the non-erodible layer impacted sediment yield and rate of upstream advance.