Assessment of climate variability impact on rainfall regimes and groundwater resources in southern Tunisia

Abstract : In arid regions where precipitation is weak and intermittent, the aquifer recharge is an important issue to evaluate groundwater resource and its future evolution in a context of excessive water request increase and climate change. A Multivariate statistical analysis of rainfall variables and atmospheric conditions factors was applied in an attempt to define the climate variability in Tataouine basin (107 mm of mean annual rainfall from 1987 to 2014), and assess its impact on rainfall regimes and the recharge of the Continental Intercalaire aquifer (CI). The present work is based on a dataset of 11 variables over the period from 1984 to 2003 (i.e. rainy days frequencies, P1 (1-10 mm), P2 (10 to 30 mm), P3 (30 to 50 mm), P4 (> 50 mm) and P0 (number of no rainy day between 2 events), mean monthly rainfall (Pm), mean monthly temperature (T), mean maximum temperature (T1), mean minimum temperature (T2), thermal amplitude (TA= T1-T2) and the mean monthly relative humidity (H)). The linear regression predictive model applied to assess the long-term trends of rainfall variation showed that the annual variation of rainfall is related to the changes of Pm, P3, P4, T1, AT, and H rather than P0, P1, P2 and T2. It appeared that annual rainfall variation is related to rainfall fr equency and depends on the amount of rainfall events. Also the air temperature and the relative humidity of the air are factors of the temporal variability of the rainfall regimes. The analysis of rainfall variability based on ‘Nicholson’ over the time series extending from 1987-2014 has allowed to highlight the presence of an excess period from 1987 to 1999 and a deficit period from 1999 to 2014. It was shown that the recharge process is not correlated with soil humidity state but with higher rainfalls involving surface flow concentration through wadis, the main recharge mode, spatially limited in this context.
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https://hal.umontpellier.fr/hal-02125371
Contributeur : Pascale Roussel <>
Soumis le : vendredi 10 mai 2019 - 14:09:18
Dernière modification le : mardi 28 mai 2019 - 13:48:10

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  • HAL Id : hal-02125371, version 1

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Zahra Dhaoui, J.D. Taupin, Kamel Zouari, Rachid Faraouni. Assessment of climate variability impact on rainfall regimes and groundwater resources in southern Tunisia. 43rd IAH International Congress “Groundwater and society : 60 years of IAH”, Sep 2016, Montpellier, France. ⟨hal-02125371⟩

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