Morgan, SavannahHuffaker, RayGiménez Díaz, RafaelCampo-Bescós, MiguelMuñoz Carpena, RafaelGovers, G.2023-03-272023-03-272022Morgan, S., Huffaker, R., Giménez, R., Campo-Bescos, M. A., Muñoz-Carpena, R., & Govers, G. (2022). Experimental evidence that rill-bed morphology is governed by emergent nonlinear spatial dynamics. Scientific Reports, 12(1), 21500. https://doi.org/10.1038/s41598-022-26114-02045-232210.1038/s41598-022-26114-0https://academica-e.unavarra.es/handle/2454/44960Past experimental work found that rill erosion occurs mainly during rill formation in response to feedback between rill-flow hydraulics and rill-bed roughness, and that this feedback mechanism shapes rill beds into a succession of step-pool units that self-regulates sediment transport capacity of established rills. The search for clear regularities in the spatial distribution of step-pool units has been stymied by experimental rill-bed profiles exhibiting irregular fluctuating patterns of qualitative behavior. We hypothesized that the succession of step-pool units is governed by nonlinear-deterministic dynamics, which would explain observed irregular fluctuations. We tested this hypothesis with nonlinear time series analysis to reverse-engineer (reconstruct) state-space dynamics from fifteen experimental rill-bed profiles analyzed in previous work. Our results support this hypothesis for rill-bed profiles generated both in a controlled lab (flume) setting and in an in-situ hillside setting. The results provide experimental evidence that rill morphology is shaped endogenously by internal nonlinear hydrologic and soil processes rather than stochastically forced; and set a benchmark guiding specification and testing of new theoretical framings of rill-bed roughness in soil-erosion modeling. Finally, we applied echo state neural network machine learning to simulate reconstructed rill-bed dynamics so that morphological development could be forecasted out-of-sample.application/pdfeng© 2022, The Author(s). This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.Rill-bed morphologyEmergent nonlinear spatial dynamicsinfo:eu-repo/semantics/article2023-03-27info:eu-repo/semantics/openAccess