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61.
Jan Nyssen Wim Clymans Katrien Descheemaeker Jean Poesen Ine Vandecasteele Matthias Vanmaercke Amanuel Zenebe Marc Van Camp Mitiku Haile Nigussie Haregeweyn Jan Moeyersons Kristine Martens Tesfamichael Gebreyohannes Jozef Deckers Kristine Walraevens 《水文研究》2010,24(13):1880-1895
Impact studies of catchment management in the developing world rarely include detailed hydrological components. Here, changes in the hydrological response of a 200‐ha catchment in north Ethiopia are investigated. The management included various soil and water conservation measures such as the construction of dry masonry stone bunds and check dams, the abandonment of post‐harvest grazing, and the establishment of woody vegetation. Measurements at the catchment outlet indicated a runoff depth of 5 mm or a runoff coefficient (RC) of 1·6% in the rainy season of 2006. Combined with runoff measurements at plot scale, this allowed calculating the runoff curve number (CN) for various land uses and land management techniques. The pre‐implementation runoff depth was then predicted using the CN values and a ponding adjustment factor, representing the abstraction of runoff induced by the 242 check dams in gullies. Using the 2006 rainfall depths, the runoff depth for the 2000 land management situation was predicted to be 26·5 mm (RC = 8%), in line with current RCs of nearby catchments. Monitoring of the ground water level indicated a rise after catchment management. The yearly rise in water table after the onset of the rains (ΔT) relative to the water surplus (WS) over the same period increased between 2002–2003 (ΔT/WS = 3·4) and 2006 (ΔT/WS >11·1). Emerging wells and irrigation are other indicators for improved water supply in the managed catchment. Cropped fields in the gullies indicate that farmers are less frightened for the destructive effects of flash floods. Due to increased soil water content, the crop growing period is prolonged. It can be concluded that this catchment management has resulted in a higher infiltration rate and a reduction of direct runoff volume by 81% which has had a positive influence on the catchment water balance. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
62.
¶rt;au uu aum nuuumu u aumnuu ¶rt; aa aam n¶rt; am amuu u namuu ¶rt;au. amu uu aumnuu nuuumu, a amu ¶rt;au, m ¶rt;mu au ma nma aaumu m¶rt; ¶rt;a, m a amu uu aum m mnu n¶rt;u ¶rt; mm uaum amua n¶rt; ¶rt;au. u aumnuu nu a namu ¶rt;auu(<1%) a uuu m nuuumu i uaum amua. u aumnuu ¶rt;mu uu uum aauuau ¶rt;ua am m uu, m, m ¶rt; u au namu ¶rt;auu. 相似文献
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Ladislav Křivský Jan Laštovička Reviewer S. Krajčovič 《Studia Geophysica et Geodaetica》1979,23(4):393-394
a¶rt;a ma nu an u u (SID) u nu n a (a n¶rt; au) mu 1965–1975
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Plastic particles were found to be common pollutants in stomachs of Wilson's Storm Petrels and Cape Petrels breeding on the Antarctic continent. Highest incidence of plastics was found in chicks of Wilson's Storm Petrels that had died before fledging. Few or no plastics were found in Snow Petrels and Antarctic Petrels. Evidence suggests that most plastics originate from wintering areas outside the Antarctic, and that relatively few plastics are available in Antarctic waters. Possible hazards of plastic levels observed in Wilson's Storm Petrels are discussed. 相似文献
66.
Thomas Foken Jan Pretel Reviewer J. Bednář Reviewer Z. Jaňour 《Studia Geophysica et Geodaetica》1988,32(3):318-328
In the present paper the first results of the international KOPEX-86 experiment are presented. The experiment took place at the Kopisty Atmospheric Observatory of the Institute of Physics of the Atmosphere in Prague as part of a special project of the Commission of the Academy of Sciences in Planetary Geophysics (KAPG) in June and July 1986. Using 4 ultrasonic anemometers at 4 levels up to 80 m, Doppler-SODAR and wind-, temperature- and radiation balance gradients from 2 to 80 m, a complex investigation of the atmospheric boundary layer in an industrial area was made. The authors present the first results of
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相似文献
| the anthropogenic influence on the energy exchange in the atmospheric boundary layer. |
| the influence of a complex terrain on the turbulent characteristics and their vertical distribution. |
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