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首页> 外文期刊>Earth Surface Processes and Landforms: The journal of the British Geomorphological Research Group >Modelling the decadal dynamics of reach-scale river channel evolution and floodplain turnover in CAESAR-Lisflood
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Modelling the decadal dynamics of reach-scale river channel evolution and floodplain turnover in CAESAR-Lisflood

机译：凯萨 - 林普敦北径河流渠道演化与洪泛平流造型的二等动力学

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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. (c) 2020 The Authors. Earth Surface Processes and Landforms Published by John Wiley & Sons Ltd.
机译：沉积存款提供了通过天然和人为紊乱调节的环境变化量化量化的记录。这些助熔剂被内部储存滞后，特别是在洪水中，使环境变化的重建复杂。时间沉积物仍然存在于沉积记录的解释和对污染物势态的准确监测。周转时间是侵蚀每个泛洪叶表面的时间范围的量度。 Caesar-leisflood用于模拟速度范围的河流演变，为量化沉积物储存时间表的环境变化提供了基础。我们评估凯撒 - 螺丝型频道变化模拟的准确性，使用历史渠道变化，在英格兰北部重建的历史渠道变化进行了调查，以量化模型准确性，以复制平均年度侵蚀，沉积和通道横向迁移率，以及平面形态。这里，采用了分流试验方法，由此校准五个达到的达到达到的达到达到的参数值，以评估参数设置的可转换性。总体集成误差最低确定了最佳的模拟，并显示建模过程率通常在历史重建的率的25-50％以内。一些达到的校准参数可广泛转移，为某些未校准部位产生准确的地貌变化。但是，沿着某些达到的大错误表明建议使用达到特定的参数化。营业额期通过假设渠道先前不受审查的洪泛区区域的假设是基础的。这种假设是通过展示洪泛区（重新）占用率在空间上变化的研究挑战。但是，这种限制对于此处呈现的短期模拟不太重要。仿真重建了大多数成功映射率估计的洪泛区营业额，展示了校准参数的潜在适用性，而不是更长的时间表。预测侵蚀率的形式误差传播，导致更大的幅度超越营业额甚至更大。 （c）2020作者。 John Wiley＆Sons Ltd.出版的地球表面流程和地貌

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