Forest impact on floods due to extreme rainfall and snowmelt in four Latin American environments 2: Model analysis
Forest impact on floods due to extreme rainfall and snowmelt in four Latin American environments 2: Model analysis
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DOI：
10.1016/j.jhydrol.2010.09.001
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发表时间：
2011-04-11
影响因子：
6.4
通讯作者：
Sarandon, Ramiro
中科院分区：
文献类型：
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作者：
Bathurst, James C.;Birkinshaw, Steve J.;Sarandon, Ramiro
通过对哥斯达黎加（131公里(2)）、厄瓜多尔（10公里(2)）、智利（0.35公里(2)）和阿根廷（12.9公里(2)）集中集水区的系统建模分析，验证了这一假设，即随着水文事件规模的增加，森林覆盖对峰值流量的影响变得不那么重要。对于每个焦点集水区，生成了代表当前气候的1000年合成降雨时间序列。该时间序列用于运行SHETRAN水文模型，用于每个集水区的两种不同的土地利用情景（通常有森林覆盖和没有森林覆盖）。然后比较了不同情景下对应的最大日流量，以显示随着峰值流量的增加，两种响应的收敛程度。对于一个给定的森林集水区排放，可能有一系列更大的非森林集水区排放，这取决于先前的土壤水分含量。模拟结果一致表明，在降雨量占主导地位的地区，随着流量的增加，这一范围的宽度要么保持不变，要么变窄，表明响应的相对收敛或绝对收敛。对于融雪状态，这种模式更难区分，但反应的相对趋同似乎仍然是可能的。因此，结果支持检验假设。然而，受流域规模、土壤深度、先前含水量和土地管理等因素的影响，这种模式变得复杂。森林还可能在中度（和更频繁）降雨事件中提供显著的减轻洪水效益，并在各种事件中防止土壤侵蚀和沉积物运输。(C) 2011 Elsevier B.V.版权所有
Through a systematic modelling analysis for focus catchments in Costa Rica (131 km(2)), Ecuador (10 km(2)), Chile (0.35 km(2)) and Argentina (12.9 km(2)), the hypothesis is tested that, as the size of the hydrological event increases, the effect of forest cover on the peak discharge becomes less important. For each focus catchment, a 1000-year synthetic rainfall time series was generated, representative of the current climate. This time series was used to run SHETRAN hydrological models for each catchment with two contrasting land use scenarios (generally with and without a forest cover). The corresponding maximum daily discharges for the contrasting scenarios were then compared to show the extent to which the two responses converged as the size of the peak discharge increased. For a given forest catchment discharge there could be a range of larger non-forest catchment discharges, depending on antecedent soil moisture content. The simulations show consistently for the rainfall dominated sites that the width of this range either remains constant or narrows as discharge increases, indicating either relative or absolute convergence of the responses. The pattern is more difficult to distinguish for a snowmelt regime but a relative convergence of response still appears possible. The results therefore support the test hypothesis. However, the pattern is complicated by factors such as catchment scale, soil depth, antecedent moisture content and land management. Forests may also still offer significant flood mitigation benefits for moderate (and more frequent) rainfall events and they protect against soil erosion and sediment transport for a wide range of events. (C) 2011 Elsevier B.V. All rights reserved.