Spatio-temporal stability of micro-dams as mitigation measures and disconnective elements to water erosion in potato farming

Abstract

Micro-dams in potato fields help reduce surface runoff and soil loss. This study evaluated their stability by examining the effects of topography, rainfall intensity, and cover crops on failure mechanisms. Micro-dams were categorized as either without cover crops (MD) or with cover crops (MD + CC), which acted as potential stabilizing factors. Field observations and UAV imagery were taken from five potato fields in Northeast Austria to create a spatio-temporal inventory of failed micro-dams. The UAV imagery enabled the construction of Digital Elevation Models (DEM) for all observations, with failure detected through an automatic routine and compared to in-field mapping. Various topographic factors, such as slope steepness and the Topographic Wetness Index (TWI), were used to classify micro-dams into stable, damaged, or broken states. Rainfall intensities were calculated to compare triggering events, and a Generalized Additive Model (GAM) assessed the resilience of micro-dams across Austria’s main potato production areas. Results indicated that MD + CC were 20 % less likely to break (OR = 0.31, 95 % CI: 0.24 – 0.41, p < 0.001), showcasing a higher proportion of stable micro-dams. These differences were significant among all state classes. MD + CC exhibited both damaged and stable micro-dams in topographic areas where standard MD had failed. The GAM results also pointed to a more sustainable performance for MD + CC. While an exact rainfall intensity threshold for failure was not established, specific conditions (53 mm total rainfall and 27.7 mm h⁻¹ intensity) were identified as indicative until future research is undertaken.