Proceedings of the 2023 Mississippi Water Resources Conference

Year: 2023 Authors: Wodajo L., Rad P., Islam S., Hickey C., Wilson G.

Ephemeral gullies result from the junction of rills that form a branching or tree-like pattern of channels. They can also be formed by internal erosion that leads to pipe (tunnel) collapse. These gullies usually appear on a cultivated field during the planting or growing season and can be partially or totally erased and filled by tillage operations. The filling leaves the nutrient-rich topsoil vulnerable to erosion leading to soil deterioration and poor crop production over a larger area than the gully itself. This paper evaluates the feasibility and efficiency of two geophysical methods, ground penetrating radar (GPR) and electromagnetic induction (EMI), for delineating soil pipes in cross-sectional and plan-view maps. The study site, currently used for pasture and crop production, is located within the Goodwin Creek experimental watershed (GCEW) of North Mississippi. The area is affected by multiple pipe collapse features, such as flute holes, sinkholes, and small to large gully windows. The erosion pipes are located at a shallow depth of less than 2m with varying lengths and widths. Geophysical signatures from the two methods are evaluated using a composite (combined) cross-section plot that includes results of an invasive technique known as cone penetrologger testing (CPL). These signatures are then used to construct plan-view maps of the area. The EMI results allow for the delineation of larger zones of fields having soil pipe networks. The GPR data provides a much better resolution. The GPR data can be used to construct maps (depth slices) representing different depths. The results demonstrate the high potential of EMI and GPR as valuable tools for studying internal soil pipes. This work was supported by the U.S. Department of Agriculture under Non-Assistance Cooperative Agreement 58-6060-6-009. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the U. S. Department of Agriculture.