Sediment transport by land (2022)

Soil erosion leads to sediment transport through the landscape until sedimentation occurs on land or the sediment flow reaches watercourses, canals or sewers. This data layer represents the modelled sediment transport, expressed in tonnes of sediment flowing downstream on average annually at a certain location in the landscape. The modelling was carried out with the CN-WS model version 4.2.3 in combination with pycnws version 0.6.3. The calculation was done on a scale of Flanders at a resolution of 20 m. This data layer is an indication of the average sediment transport calculated with an average precipitation erosivity factor of the last 30 years. Scenario A was applied, whereby agricultural parcels are considered grassland when they have a permanent crop cover for at least 2 consecutive years. All other agricultural parcels are considered to be average arable land. The modelling is based on the 2022 agricultural parcel map. The anti-erosion measures implemented in 2022 through management agreements or small-scale anti-erosion works were taken into account. Locally, the modelled values may differ from the real values, as each modelling is only an approximation of reality. Moreover, only the input data that is available and part of the model can be taken into account.土壤侵蚀会导致泥沙在地表景观中输移，直至泥沙在陆地沉积，或是泥沙流进入河道、沟渠或下水道。本数据图层代表经建模得到的泥沙输移量，以某一景观位置处年均向下游输移的泥沙吨数进行表征。本次建模采用CN-WS模型（CN-WS model）4.2.3版本，结合pycnws 0.6.3版本完成。计算范围覆盖佛兰德斯地区，空间分辨率为20米。本数据图层为基于过去30年平均降雨侵蚀力因子计算得到的平均泥沙输移量参考值。已应用情景A：若农业地块连续两年及以上具备永久性作物覆盖，则将其归类为草地；其余农业地块均视为普通耕地。本次建模基于2022年农业地块地图开展，并纳入了2022年通过管理协议或小型侵蚀防治工程实施的各项侵蚀防治措施。由于每一次建模仅为现实情况的近似模拟，局部建模结果可能与实际观测值存在偏差；此外，模型仅能纳入已获取并作为模型输入的相关数据。