Distributed water erosion modelling at fine spatial resolution across Denmark
| Autor: | Antoine Stevens, Mette B. Greve, Kristof Van Oost, Nils Onnen, Johannes Wilhelmus Maria Pullens, Brian Kronvang, Goswin Heckrath, Preben Olsen |
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| Přispěvatelé: | UCL - SST/ELI/ELIC - Earth & Climate |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
EQUIFINALITY
EUROPE 010504 meteorology & atmospheric sciences Denmark CONSERVATION UNCERTAINTY 010502 geochemistry & geophysics WaTEM 01 natural sciences HILLSLOPE SEDIMENT DELIVERY Agricultural land MANAGEMENT RATES 0105 earth and related environmental sciences Earth-Surface Processes National modelling Hydrology geography geography.geographical_feature_category SOIL-EROSION LANDSCAPE Sediment Water resources Rill Erosion PATTERNS Soil erosion Spatial variability Surface water Sediment transport Geology |
| Zdroj: | Onnen, N, Heckrath, G, Stevens, A, Olsen, P, Greve, M B, Pullens, J W M, Kronvang, B & Van Oost, K 2019, ' Distributed water erosion modelling at fine spatial resolution across Denmark ', Geomorphology, vol. 342, pp. 150-162 . https://doi.org/10.1016/j.geomorph.2019.06.011 Geomorphology, Vol. 342, p. 150-162 (2019) |
| DOI: | 10.1016/j.geomorph.2019.06.011 |
| Popis: | Water erosion on agricultural land and sediment delivery to streams are a major threat to soil productivity and surface water quality. Climate change and different national and international societal drivers now require Denmark to take action to protect soil and water resources. In this study, we adapted the spatially distributed sediment transport model WaTEM using the best data available at national scale. To calibrate and validate the model, sediment yield data from 31 catchments and 189 slope units in Denmark were compared with the model output, which was produced at a fine spatial resolution of 10 × 10 m. Residual analysis and cross-validation were used to identify potential catchment outliers and assess model robustness. We obtained a median Nash & Sutcliffe model efficiency range of 0.06–0.6 for the Danish environment. Based on the equifinality concept, an ensemble of 100, NSE-weighted model realisations for acceptable transport capacity coefficients was used to assess model uncertainty. The comparison between rill survey data and predicted values indicates that although the model captures well the spatial variability in erosion, it may underestimate the long-term average of soil erosion. Based on the modelling, 71% of the agricultural land in Denmark is mapped as stable in terms of the amount of erosion and deposited material. Overall, 6.1% of the farmland is estimated to have unsustainable erosion and 0.9% of the farmland exceeds erosion rates of 7.5 t ha−1 a−1. Sediment export into surface water in Denmark equals 92,000 t a−1, corresponding to an average sediment yield of 2.7 t km−2. The performance of WaTEM is considered satisfactory in this study. Importantly, modelled water erosion exceeds the perceived erosion risk in Denmark. Strengthened by distributed uncertainty assessment at national scale, our study provides an important national knowledge base for engaging land users and regulators in the process of targeted erosion mitigation planning that is required to comply with national and EU regulation. Future investigations concerning the deviation between predicted and observed data and specific catchment parameters for the non-behavioural catchments are required as well as studies that include the establishment of catchment sediment budgets. |
| Databáze: | OpenAIRE |
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