Exploring structural sediment connectivity via surface runoff in agricultural lands of Finland

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Taylor & Francis Group - Informa UK Limited
Spatial information on the distribution of erosion areas and sediment transport pathways within agricultural landscapes is limited. Thus, we assess structural sediment connectivity via surface runoff by using a digital elevation model (2 × 2 m2) and RUSLE-based erosion estimates to compute index of connectivity (IC) and sediment delivery estimates. The variables were analyzed within and between two topographically contrasting subcatchments. We found greater spatial variability of IC within a subcatchment than between the subcatchments. The majority of field parcel areas (65%–97%) were structurally connected to adjacent open ditches and streams. Areas with high erosion estimates also tended to be structurally well-connected, both at the pixel (Pearson r = 0.58–0.63) and parcel scale (r = 0.49–0.67). The IC model was not highly sensitive to parameter variations. In contrast, the magnitude of sediment delivery estimates was highly sensitive to parameter variations. However, based on the high rank correlation (Spearman rs > 0.95) between computed sediment delivery estimates, the tool provided consistent information on potentially high sediment delivery areas. More empirical data and dynamic model applications could be applied to improve the accuracy of the estimates. The method provides a feasible tool to generate open data on connectivity.
Acknowledgments: This project was funded by the EJP SOIL SCALE project. The project has received funding from the European Union’s Horizon 2020 research and innovation programme: Grant agreement No 862695. The project made use of data and geo-computing resources provided by CSC – IT Center for Science, Finland (urn:nbn:fi:research-infras-2016072531) and the Open Geospatial Information Infrastructure for Research (GeoporttiRI, urn:nbn:fi:research-infras-2016072513). © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Version of Scholarly Record of this Article is published in (Acta Agriculturae Scandinavica, Section B — Soil & Plant Science, 2022, available online at: http://www.tandfonline.com/10.1080/09064710.2022.2136583 . Keywords: Connectivity; lowlands; erosion; RUSLE; connectivity index; soil; agricultural landscapes; Europe; Finland; sediment; water protection.
M. Tähtikarhu, T. Räsänen, J. Oksanen & J. Uusi-Kämppä (2022) Exploring structural sediment connectivity via surface runoff in agricultural lands of Finland, Acta Agriculturae Scandinavica, Section B — Soil & Plant Science, 72:1, 957-970, DOI: 10.1080/09064710.2022.2136583