Modelling the decadal dynamics of reach-scale river channel evolution and floodplain turnover in CAESAR-Lisflood
Modelling the decadal dynamics of reach-scale river channel evolution and floodplain turnover in CAESAR-Lisflood
复制标题
对 CAESAR-Lisflood 河段规模河道演变和洪泛区周转的年代际动态进行建模
DOI：
10.1002/esp.4804
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发表时间：
2020
影响因子：
3.3
通讯作者：
Feeney C
中科院分区：
文献类型：
--
作者：
Feeney C
沉积物提供了环境变化的记录，量化了受自然和人为干扰影响的侵蚀通量。这些通量滞后于内部存储，特别是在洪泛区，复杂的环境变化的重建。沉积物在储存中的时间是解释沉积记录和准确监测污染物通量的基础。周转时间是侵蚀每个洪泛区表面的时间尺度。CAESAR‐Lisflood用于模拟河段尺度的河流演变，为量化沉积物存储时间尺度上的环境变化提供基础。我们评估的准确性CAESAR-Lisflood模拟的渠道变化和周转时间的冲积洪泛区使用历史的渠道变化重建的10个达到在北方英格兰量化模型的准确性复制平均年侵蚀，沉积和渠道横向迁移率，以及平面形态。在此，采用了分离样本测试方法，其中五个范围进行了校准，并将得到的参数值应用于其他范围，以评估参数设置的可移植性。最低的整体综合误差确定了最佳拟合模拟，并表明建模的过程速率通常在历史重建速率的约25-50%范围内。某些河段的标定参数具有广泛的可传递性，从而为某些未标定的站点提供了准确的地貌变化。但是，沿着某些河段的较大误差表明建议使用特定河段的参数化。周转时间的基础假设，以前未访问的渠道的洪泛区进行返工。这一假设受到了挑战的研究表明，洪泛区（再）占用率在空间上各不相同。然而，对于这里介绍的短期模拟，这种限制并不重要。模拟重建河漫滩周转时间估计映射率大多成功，表明校准参数在更长的时间尺度的潜在适用性。以低估侵蚀率的形式出现的错误传播，导致更大幅度的高估周转时间。版权所有2020作者。地球表面过程和地貌由约翰威利父子有限公司出版。
Sedimentary deposits provide records of environmental change quantifying erosion fluxes conditioned by natural and anthropogenic disturbances. These fluxes are lagged by internal storage, particularly within floodplains, complicating reconstruction of environmental changes. The time sediment remains in storage underpins the interpretation of sedimentary records and accurate monitoring of pollutant fluxes. Turnover time is a measure of the timeframe to erode every floodplain surface. CAESAR‐Lisflood is used to simulate fluvial evolution at reach scale, providing a basis for quantifying environmental changes on the timescales of sediment storage. We evaluate the accuracy of CAESAR‐Lisflood simulations of channel changes and turnover times for alluvial floodplains using historical channel changes reconstructed for 10 reaches in northern England to quantify model accuracy in replicating mean annual erosion, deposition and channel lateral migration rates, alongside planform morphology. Here, a split‐sample testing approach is adopted, whereby five of the reaches were calibrated and the resulting parameter values were applied to the other reaches to evaluate the transferability of parameter settings. The lowest overall integrated error identified the best‐fit simulations and showed that modelled process rates were within ~25–50% of rates from historical reconstructions, generally. Calibrated parameters for some reaches are widely transferable, producing accurate geomorphic changes for some uncalibrated sites. However, large errors along some reaches indicate that reach‐specific parameterization is recommended. Turnover times are underpinned by the assumption that areas of floodplain previously unvisited by the channel are reworked. This assumption has been challenged by studies that show floodplain (re)occupation rates vary spatially. However, this limitation is less important for the short‐duration simulations presented here. The simulations reconstruct floodplain turnover times estimated by mapped rates mostly successfully, demonstrating the potential applicability of calibrated parameters over much longer timescales. Errors in the form of under‐predicted erosion rates propagated, resulting in over‐predicted turnover times by even greater magnitudes. © 2020 The Authors. Earth Surface Processes and Landforms Published by John Wiley & Sons Ltd.