Characterization and Aquifer Functioning System of Haraz Al Biar (North Chari Baguirmi) Abdallah Mahamat Nour, Hamit Abderamane, Benjamin Ngounou Ngatcha, Pierre Deschamps, Camille Bouchez To cite this version: Abdallah Mahamat Nour, Hamit Abderamane, Benjamin Ngounou Ngatcha, Pierre Deschamps, Camille Bouchez. Characterization and Aquifer Functioning System of Haraz Al Biar (North Chari Baguirmi). International Journal of Current Research and Academic Review, 2017, 5 (12), pp.52 - 64. 10.20546/ijcrar.2017.512.008. hal-01713542 HAL Id: hal-01713542 https://hal.archives-ouvertes.fr/hal-01713542 Submitted on 20 Feb 2018 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Int.J.Curr.Res.Aca.Rev.2017; 5(12): 52-64 International Journal of Current Research and Academic Review ISSN: 2347-3215 (Online) ҉҉ Volume 5 ҉҉ Number 12 (December-2017) Journal homepage: http://www.ijcrar.com doi: https://doi.org/10.20546/ijcrar.2017.512.008 Characterization and Aquifer Functioning System of Haraz Al Biar (North Chari Baguirmi) A. Mahamat Nour1, 2*, H. Abderamane1, B. Ngounou Ngatcha3, P. Deschamps2 and Bouchezc2 1University of N'Djamena - Department of Geology, N'Djamena, Chad 2Aix Marseille University, CNRS, IRD, College of France, UMR-CEREGE, Mediterranean Technopole of Arbois, Aix-en-Provence, France 3University of Ngaoundere, Faculty of Sciences, Ngaoundéré, Cameroon *Corresponding author Abstract Article Info Haraz Al Biar (Northern Chari-Baguirmi) is located in the semi-arid zone, limited to Accepted: 30 November 2017 the north by Lake Chad and on the west by Chari - Logone. The study of Haraz Al Biar Available Online: 20 December 2017 aquifer system aims to improve its knowledge for the sustainable management of groundwater resources. In the study area, water sampling campaigns were realized. Keywords These samples have been the subject of the study of hydrodynamic and hydrochemical parameters of the aquifer system. The piezometric data show that the transfer of water Haraz al Bar, from Lake Chad is hydraulically possible because the level of the lake is above the Lake Chad Basin, static level of the water table. The chemical data allowed to distinguish the difference Hydrochemistry, between bicarbonate and sulphate facies. Hydrodynamical, Depression Introduction their depth and the quality of water from one point to another. Pressures on groundwater are more and more The surface waters are scarce or absent in arid and semi- increasingly important due to changes in consumption arid area (Joly, 2006; SFDI, 2011), groundwater often patterns (Margat, et al., 2008), the increase in world makes up the essential to the mobilization of water population and the corresponding needs (agriculture, resources or the ones likely to be (SFDI, 2011; Bensaâd, drinking water, industry, energy, etc.).Their impact can 2011; Merem-Farah, 2017). The groundwater is part of a be very harmful (lowering of groundwater level, category of difficult resources to grasp. It typically falls impaired water quality, land subsidence, saltwater under the environmental goods and seem to belong to intrusion, pollution, loss of biodiversity, etc.) in the everyone, at the same time they do not belong to no one short, medium or long term and irreversible or with (Olivier, 2004). The Sahelian areas suffer from a strong significant restoration costs (Sylvie, 2001; Olivier, environmental degradation due to climate change 2004). Good management, protection of water resources manifested by the decline and the randomness of rainfall and study of aquifers are a priority. (Kawtar, 2004, Ndiaye and Ndiaye, 2013). The population of these areas feeds almost themselves The Chari Baguirmi, like the other regions of the Sahel, exclusively on groundwater through wells and / or has known in the last decades and continues to suffer boreholes. These boreholes and wells are very variable in from a strong environmental degradation due to the 52 Int.J.Curr.Res.Aca.Rev.2017; 5(12): 52-64 climate contrasts affecting the Lake Chad basin. The of the Precambrian basement. This base consists scarcity of rainfall has led to the decrease level of Lake essentially of granites, migmatites, quartzites, gneiss, Chad water. This drop in water level has caused the charnockites, amphibolite, mica schists and (Gac, 1980); drying up of some streams. This phenomenon is (2) in the center and north-west, series of coverings of aggravated by the advance of the desert and the setting tertiary-age sandstone sediments and late Quaternary up of sands. These conditions have forced the people fluvial or fluvial-lacustrine of current Quaternary. leading a farming activity transhumance who make use of groundwater through traditional wells and boreholes The Quaternary formations are characterized by their daily needs. alternations of deposits between wet and dry poles (Schneider and Wolff, 1992). Lack of surveillance network in Chari - Baguirmi in general and Haraz Al Biar in particular is a major More locally (study area), there are two rhyolitic massifs problem to characterize precisely the hydrodynamic and (Hadjer El Hamis and Hadjer Bigli).They gathered at hydro-chemical functioning of this sheet. Maastrichtian K/Ar 68.9 ± 1.4 My was determined at Hadjer Bigli (Schroeter and Gear,1973). Granite points In this sector, the studies carried out by Schneider and could be even more recent, tertiary, if one accepts an Bonnet, 1968; BRGM, 1987; Schneider and Wolff, 1992; analogy with the data of North Cameroon. The oldest Daira, 2000; Abderamane, 2012 and Bouchez, 2015 have formations probably correspond to the Pan-African. set surface water links (Logone-Chari system and Lake Chad) with the aquifer of the Quaternary. The Much of the soil Haraz Al Biar area was formed on groundwater levels are lower along Chari and Logone fluviolacustrine alluvial deposits of the Chad basin (Pias, increasingly deep as one gets to be distant from Chari- 1964; Pias, 1968; Cesar, 1990). There is a quaternary Logone (Daira, 2000; Abderamane, 2012). To date, few clay lake series and a sub-current to present alluvial studies have been conducted in order to make clear the series partially superimposed on the previous one (Pias, relationship between the sheet of Haraz Al Biar and 1970). According to these authors, these formations gave surface water on one hand; to characterize the rise to two major types of soils (1) vertisols resting on a hydrodynamic and hydrochemical functioning on the dark clay, tropical, occupying the lacustrine areas; (2) other hand. pseudo Gley soils with stains and concretions whose texture is sandy-loamy. These were formed from recent Natural Framework alluvium. Location of the study area The description of the hydrogeological framework is essentially based on that of the Tertiary and Quaternary The Lake Chad basin is located in Central Africa geological formations. The aquifer Pliocene essentially between 6° and 24° North latitude and 8° and 24° East consists of an alternation of sand and clay beds 5 to 10m longitude. It occupies an area of about 2.5 million square in thickness to a maximum total thickness of 120 m km or 8% of the area of Africa. It is bordered by the (Schneider, 2001). On the scale of the Chad basin, the relief of Adamawa south, the Tibesti in the north of flow is from south to north-east of Chad where Ouaddai in the east of Jos in the southwest and Hoggar in groundwater is artesian (Schneider, 2001). Continental the northwest (Figure 1). The study area is restricted to Terminal is mostly the sandstone or sand alternating with Haraz Al Biar region (Massaguet – Djermaya – Mani- clays and sometimes conglomerates (Bouchez, 2015). Tourba) and is located in the northern part of Chari The Quaternary aquifer is characterized by a general Baguirmi. It stretches between 12.06° and 13.20° north water table. This layer consists of aeolian sands and latitude and between 14.50° and 15.90°East.This area is fluviolacustres series (Djoret, 2000; Massuel, 2001; characterized by natural sets consisting of Chari-Logone Abderamane et al., 2012). deltas, flood zones and dune ridges. The vegetation in Haraz Albiar sector (North Chari Geology, hydrogeology and vegetation Baguirmi) is composed of a Sahelian plant formation which consists of two elements (1) a herbaceous layer, The geology of Chad basin was widely studied by Louis consisting mainly of grass-dominated annuals; (2) a (1970). There are two major geological units (Figure 1): stand of woody plants (trees and shrubs) dominated (1) to the south and north-northeast, outcrop formations mainly by thorny trees. 53 Int.J.Curr.Res.Aca.Rev.2017; 5(12): 52-64 Hydro-climatic Description meter. Uncertainties about pH measurements are 0.1 unit on the electric conductivity of 10 microsiemens/cm and The climate of the study area is semi-arid tropical type. the temperature of 0.5 °C. Rainfall is marked by a strong irregularity in its spatial and temporal distribution. This irregularity is explained Sampling of water for major chemical elements by the importance of the distribution of the flow of the Guinean monsoon, the main source of moisture. It is Sampling is essential because it determines the relevance marked by a long dry season from October to May and a of the analysis. It must be of quality but also short rainy season ranging from June to September. The representative of what one wants to analyze. average interannual rainfall is 535 mm in Chari Baguirmi between 1982 and 2011, mean interannual temperatures The observation network has a total of 11Wells and oscillate between 26 ° C and 28 ° C.