The impact of upland land management on flooding: results from an improved pasture hillslope
The impact of upland land management on flooding: results from an improved pasture hillslope
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DOI：
10.1002/hyp.7157
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发表时间：
2009-01
影响因子：
3.2
通讯作者：
M. Marshall;O. Francis;Z. Frogbrook;B. Jackson;N. McIntyre;B. Reynolds;I. Solloway;H. Wheater;J. Chell
中科院分区：
文献类型：
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作者：
M. Marshall;O. Francis;Z. Frogbrook;B. Jackson;N. McIntyre;B. Reynolds;I. Solloway;H. Wheater;J. Chell
为了回应人们日益关注的高地农业用地管理对洪水风险的影响，在英国塞文河的养羊源流域庞特布伦建立了一个配备密集仪器的实验流域。主要目的是加深对控制洪水产生过程和土地管理实践的相关影响的了解，并弥合过程理解和预测下游洪水影响的能力之间的差距。为了实现这一目标，实验设计为在地块（∼100 m2）、山坡（∼0·1 km2）和小流域规模（∼10 km2）上进行。来自排水不足的农业“改良”牧场的山坡尺度数据表明，排水流是主要的径流过程。然而，根据先前的湿度条件，地表径流可能超过排水流量，并且可能是山坡尺度径流峰值的重要贡献者。流量、土壤张力数据和示踪剂测试证实了大孔隙的重要性以及“正常”潮湿条件下栖息地下水位的存在。牧场径流与 10 年树龄防护林内的径流比较表明，由于树木的存在和/或羊的缺乏，地表径流显着减少。土壤水力特性的比较表明，与邻近的改良牧场相比，树下土壤的导水率和饱和含水量显着增加。版权所有 © 2008 约翰·威利父子有限公司
In response to growing concern about impacts of upland agricultural land management on flood risk, an intensely instrumented experimental catchment has been established at Pontbren, a sheep‐farmed headwater catchment of the River Severn, UK. Primary aims are to develop understanding of the processes governing flood generation and the associated impacts of land management practices, and to bridge the gap between process understanding and ability to predict effects on downstream flooding. To achieve this, the experiment is designed to operate at plot (∼100 m2), hillslope (∼0·1 km2) and small catchment scale (∼10 km2). Hillslope‐scale data, from an under‐drained, agriculturally ‘improved’ pasture, show that drain flow is a dominant runoff process. However, depending on antecedent moisture conditions, overland flow may exceed drain flow rates and can be an important contributor to peak flow runoff at the hillslope‐scale. Flow, soil tension data and tracer tests confirm the importance of macropores and presence of perched water tables under ‘normal’ wet conditions. Comparisons of pasture runoff with that from within a 10 year‐old tree shelterbelt show significantly reduced overland flow due to the presence of trees and/or absence of sheep. Comparisons of soil hydraulic properties show significant increases in hydraulic conductivity and saturated moisture content of soil under trees compared to adjacent improved pasture. Copyright © 2008 John Wiley & Sons, Ltd.