Restoration of blanket peat moorland delays stormflow from hillslopes and reduces peak discharge
Restoration of blanket peat moorland delays stormflow from hillslopes and reduces peak discharge
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DOI：
10.1016/j.hydroa.2018.100006
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发表时间：
2019-01
影响因子：
4
通讯作者：
E. Shuttleworth;M. Evans;M. Pilkington;T. Spencer;J. Walker;D. Milledge;T. Allott
中科院分区：
文献类型：
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作者：
E. Shuttleworth;M. Evans;M. Pilkington;T. Spencer;J. Walker;D. Milledge;T. Allott
在过去的15年里，有一个旨在恢复英国高地毯沼泽的结构和功能的项目激增，主要是通过裸露泥炭的重新植被和侵蚀沟的阻塞。这些恢复措施有可能改变暴雨流量的反应，并有助于自然洪水管理，但它们对暴雨水文过程的影响很难量化。本文报道了一个前后控制干预（BACI）的研究，从三个实验性的源头微集水区在南奔宁山脉（英国）代表的第一个严格的实验评估毯泥炭恢复对集水径流的影响。我们评估了两个标准的恢复干预措施的水文影响，裸露的泥炭植被，裸露的泥炭植被与额外的沟壑阻塞。植被恢复后，地下水位深度显著下降，山坡地表径流量普遍增加。两种恢复处理后，暴雨径流系数均无显著变化。风暴过程线植被恢复后有显着更长的滞后时间（106%的增加相对于控制），减少峰值流量（27%的减少相对于控制），和衰减的过程线形状。加上沟道堵塞，效果几乎翻了一番。滞后时间增加了进一步的94%，峰值流量减少了额外的24%，相对于控制。我们认为，主要的过程控制所观察到的变化，在风暴过程线的行为是由于地表粗糙度增加的陆面风暴流的阻滞。滞后时间和峰值流量的显着变化提供的证据表明，退化的源头泥炭地的恢复可以有助于自然洪水管理和下游洪水风险的降低，受更广泛的集水区尺度效应和子集水区暴雨过程线同步性。
Over the past 15 years there has been a proliferation of projects aiming to restore the structure and function of UK upland blanket mires, primarily by revegetation of bare peat and the blocking of erosion gullies. These restoration measures have potential to alter stormflow responses and contribute to Natural Flood Management, but their impacts on storm hydrographs are poorly quantified. This paper reports a before-after-control-intervention (BACI) study from three experimental headwater micro-catchments in the South Pennines (UK) representing the first rigorous experimental assessment of the impact of blanket peat restoration on catchment runoff. We evaluate the hydrological impacts of two standard restoration interventions; revegetation of bare peat, and revegetation of bare peat with additional gully blocking. Following revegetation there was a significant decrease in depth to water table and an increase in the prevalence of hillslope overland flow production. There were no significant changes in storm runoff coefficient following either restoration treatment. Storm hydrographs following revegetation had significantly longer lag times (106% increase relative to the control), reduced peak flows (27% decrease relative to the control), and attenuated hydrograph shapes. With the addition of gully blocking the effect is almost doubled. Lag times increased by a further 94% and peak flows reduced by an additional 24% relative to the control. We argue that the primary process controlling the observed changes in storm hydrograph behaviour is retardation of overland stormflow due to increased surface roughness. The significant changes to lag times and peak flow provide evidence that the restoration of degraded headwater peatlands can contribute to Natural Flood Management and the reduction of downstream flood risk, subject to wider catchment scale effects and sub-catchment storm hydrograph synchronicity.