Seminar: Determining Management Effects on Ephemeral Gully Erosion and Deposition   Wesley Wright Research Associate I Friday, November 06, 2009 2:30 to 3:20 pm Accurate estimates of total sediment yield are useful for determining downstream water quality impacts, long-term productivity of fields, and landscape degradation. The soil erosion produced in ephemeral gullies is approximately equal to that produced by rill-interrill erosion in tillage based production fields and can account for as much as ninety percent of the sediment yield from hay, pasture, and no-till production fields. However, researchers have found that as much as eighty percent of the sediment detached by rill-interrill and ephemeral gully erosion does not leave the field due to deposition within the gullies. Currently, the soil conservation-planning tool RUSLE2 does not include a detachment/deposition component for ephemeral gullies. Therefore, RUSLE2 is a soil conservation management tool for rill-interrill erosion, because it does not provide total sediment yield estimates from a field scale. Foster (2005) proposed an ephemeral gully component for RUSLE2 patterned on the process-based models presented in Foster (1982). Many of the parameters of the model are sensitive to factors that can be affected by erosion management. As noted by Foster (2005), the parameter models for conveyance channel geometry, soil critical shear stress and erodibility, and flow transport capacity require further evaluation based on recent literature. This dissertation work has addressed all three of these parameter models, but this presentation will emphasize on the derivation of a conveyance function for channel geometry and the evaluation of the Yalin transport capacity equation. Rm 266, BESS Lab Building 2500 E.J. Chapman Drive West Campus Biosystems Engineering & Soil Science · bess@utk.edu · bioengr.ag.utk.edu · 974-7266