Experimental and modelling evidence of short-term effect of raindrop impact on hydraulic conductivity and overland flow intensity

JOURNAL OF HYDROLOGY

卷:570

Article

Mugler, Claude¹  Ribolzi, Olivier²  Janeau, Jean-Louis³  Rochelle-Newall, Emma³  Latsachack, Keooudone⁴  Thammahacksa, Chanthamousone⁴  Viguier, Marion⁴  Jarde, Emilie⁵  Henri-Des-Tureaux, Thierry⁴  Sengtaheuanghoung, Oloth⁶  Valentin, Christian³ 

[1] UMR 8212 CEA CNRS UVSQ, Lab Sci Climat & Environm, Orme Merisiers, F-91191 Gif Sur Yvette, France

[2] UMR 5563 CNRS UPS IRD, Geosci Environm Toulouse, 14 Ave Edouard Belin, F-31400 Toulouse, France

[3] Univ Paris Diderot, Sorbonne Univ, iEES Paris,Inst Ecol & Sci Environm Paris, IRD,CNRS,INRA,UPEC, CC237 4 Pl Jussieu, F-75005 Paris, France

[4] Inst Ecol & Sci Environm Paris, IRD iEES Paris, Dept Agr Land Management DALaM, POB 4199, Xaythany Dist, Vientiane, Laos

[5] Univ Rennes, CNRS, UMR 6118, Geosci Rennes, F-35000 Rennes, France

[6] Minist Agr & Forestry, ALUPC, Viangchan, Laos

关键词: Runoff modelling;    Raindrop impact;    Hydraulic conductivity;    Soil crusting;    Tropical agro-ecosystems;    Lao PDR;   

DOI  :  10.1016/j.jhydrol.2018.12.046

来源: Elsevier

【 摘 要 】

Tropical montane areas of Southeast Asia are exposed to high-intensity rainfall during the monsoon period. This is particularly problematic in areas where soils on steep slopes are cultivated as it can lead to heavy runoff, high soil erosion, and water pollution. The objective of this paper is to analyse the effect of the impact of raindrops on the dynamics of runoff on such steep fields. Experiments under simulated rainfall were performed at the plot scale (1 m(2)) to quantify water export from the surface of upland agricultural soils during overland flow events. Four 1 m(2) plots were divided in duplicated treatment groups: (a) control with no amendments, and (b) amended with pig manure. Each plot was divided into two 0.5 m(2) rectangular subplots. One subplot was designated as a rain splash treatment; the other sub-plot was covered with a 2 mm grid size wire screen that was located 12 cm above the soil surface. The purpose of the screen was to break the raindrops into fine droplets and to reduce fall height in order to drastically reduce their kinetic energy. Runoff was measured for each sub-plot. The results show that raindrop impact drastically enhances runoff generation on both bare soils and on manure amended soils. When the impact of raindrops was limited by screening, runoff was higher on amended soils than on bare soils. The temporal evolution of runoff was correctly modelled using a soil hydraulic conductivity that exponentially decreases over time of exposure to rainfall. Both experimental and modelling results showed that droplet energy induces a rapid evolution of the hydraulic properties of the soil surface due to crusting, resulting in a reduction of hydraulic conductivity and a concomitant increase in runoff rate.

【 授权许可】

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