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ARS Home » Research » Publications at this Location » Publication #94499
Title: HEADCUT DYNAMICS AND EPHEMERAL GULLY EROSION

Author
item Robinson, Kerry
item Bennett, Sean
item CASALI, JAVIER - PUB UNIV NAVARRA, SPAIN

Submitted to: American Society of Agricultural Engineers Meetings Papers
Publication Type: Proceedings
Publication Acceptance Date: 8/1/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: The formation and movement of large and small gullies causes large soil losses and introduces large amounts of sediment into our nation's waterways. Gullies can also cause bank stability problems, threaten earth dams, and undermine roads and bridges. Experimental research examined the rates of small gully movement and the scour hole geometry. Field research examined gullies in Mississippi and Spain, and despite large differences i climate and watershed size the gullies were found to be similar. The factors influencing the movement of large gullies are also described. These results suggest that there are many similarities in the growth and movement of gullies of all sizes. This information is helpful in determining methods to minimize gully erosion. This study should be of interest to a wide range of disciplines interested in headcut erosion in rills and gullies.

Technical Abstract: The formation and upstream migration of headcuts and ephemeral gullies significantly increases soils losses and sediment yields from agricultural lands, threatens the structural integrity of earthen dams, and can undermine roads and bridges. Erosion prediction technology would be greatly improved if the contribution by headcuts and ephemeral gullies could be included. Recent experimental and field research have provided new insight on these erosion processes. During migration, headcut shape, size, and rate of movement, and sediment yield remained constant. Downstream of the headcut, a soil bed was constructed where slope was dependent upon the sediment yield from the headcut and the flow transport capacity. Field research in Mississippi and Spain concluded that despite the large differences in climate, watershed size, hydrology, and geography, the ephemeral gullies observed in Spain were morphologically similar to those in Mississippi. Large-scale gully erosion processes were also examined, an the influence of soil density, flow rate, overfall height, and backwater level on headcut advance rate are discussed. The mechanics of headcut erosion, in both rills and gullies, are discussed.