| Abstract: | The formation of ephemeral gullies can significantly increase soil loss from agricultural lands and severely impact farm productivity. Erosion prediction technology and conservation management techniques would be greatly improved if the contribution from ephemeral gullies could be more accurately quantified. Field research in Mississippi, U.S.A. and Spain has revealed three categories of ephemeral gullies. Classic ephemeral gullies formed by concentrated flow erosion from runoff occurring within the same field. Drainage ephemeral gullies formed by concentrated flow erosion from runoff originating from areas upstream of where the gully occurs. Discontinuity ephemeral gullies formed in areas where management practices have created a sudden change in slope, such as field boundaries adjacent to roads.Despite the large differences in climate, watershed size, hydrology, and geography, the ephemeral gullies observed in Spain were morphologically similar to those in Mississippi. Using an experimental flume,ephemeral gully erosion proceeded primarily through bed incision, gully widening, and bank steepening,and total sediment load depended upon whether the flow was detachment- or transport-limited. |
