文章基本信息

标题：ENVIRONMENTAL TRACERS AS INDICATORS OF WATER FLUXES THROUGH THE UNSATURATED ZONE IN SEMIARID REGIONS: THE CASE OF GAFSA PLAIN (SOUTHERN TUNISIA)
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作者：Messaouda Yermani ; Najiba Chkir ; Kamel Zouari 等
期刊名称：Journal of Environmental Hydrology (ältere Jahrgänge)
印刷版ISSN：1058-3912
电子版ISSN：1996-7918
出版年度：2009
卷号：17
出版社：IAEH
摘要：Isotopic and chloride investigations have been conducted to estimate local hydrologic processes taking place in the semiarid Gafsa Plain (Southern Tunisia). A sandy soil core has been sampled at one site where the water table is at about 6 m depth and where water level fluctuations indicate a direct recharge of the shallow aquifer. Oxygen 18 and chloride data have been interpreted using the model of Barnes and Allison to suggest that evaporation rates from groundwater average around 11 mm/y. The rates from the shallow aquifer level to the soil surface range from 7 to 22 mm/y. The model parameters highlight that evaporation mechanisms are increasingly dominated by vapor phase transfers as the thickness of the layer through which water evaporates increases. The recharge rates by direct rainfall infiltration have been estimated by chloride mass balance method to range from 3 to 5 mm/y, with a mean value of 3.9 mm/y. This represents about 2.4% of local rainfall (164 mm/year). The long residence time of 77.8 years shown by the 6m depth chloride profile indicates slow recharge processes.