Christian Leduc

Christian Leduc
Institute of Research for Development | IRD

PhD + HDR

About

160
Publications
27,557
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3,498
Citations
Citations since 2017
25 Research Items
1455 Citations
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2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250

Publications

Publications (160)
Preprint
Full-text available
The Wadi Merguellil, the main watercourse of the Merguellil basin in central Tunisia, has experienced an extremely marked socio-hydrological evolution. It is currently intermittent over most of its course, but the statements of farmers and archival records reveal that this was not the case at the beginning of the last century. They testify their no...
Article
Full-text available
Hydrogeology in the Andes cordillera reflects its complex geological history. In most cases, groundwater flows through fractures and faults that compartmentalize the volcanic material, and through the primary porosity of the volcano-sedimentary material. The volcanic mineral context and geothermal environment mark the groundwater chemistry, especia...
Article
Full-text available
In Tunisia, the discharge of treated wastewater onto land area has become a common practice, especially in arid and semi-arid regions where there are no permanent rivers to receive discharge. Treated wastewater constitutes a potential anthropogenic source of aquifer recharge as is the case for the alluvial aquifer downstream of the Kairouan plain....
Chapter
Full-text available
In parallel with the conference on climate change organized from 7 to 18 November 2016 at Bab Ighli in Marrakech in Morocco, a book entitled: "The Mediterranean Region under Climate Change A Scientific Update" was published by I.R.D. We participated in this project with a chapter under the theme: "Changes in Mediterranean groundwater resources"
Poster
Full-text available
The Plio-Quaternary aquifer in the Kairouan plain (central Tunisia, 3000 km2) represents a key resource for the agricultural development of the region. To date, hydrological studies consider that a part of the water of this large aquifer is discharging in the Sebkha Kelbia, topographic depression (120 km2). Regarding the continuous groundwater leve...
Article
Full-text available
La forte croissance de la demande en eau au Maghreb pousse les autorités locales à construire de plus en plus de barrages pour augmenter la disponibilité des ressources en eau, naturellement limitée, et faire face à la forte irrégularité temporelle (saisonnière et interannuelle) des précipitations. L’Algérie dispose ainsi de 57 grands barrages d’un...
Article
Grombalia region (NE Tunisia) exploits multiple sources of water: groundwater from shallow and deep aquifers, local surface water, and external surface water transferred from the North-west of Tunisia (Medjerda River and Ichkeul basin). The coordinated control of the water sources is very week while no evaluation of the impact of anthropogenic acti...
Conference Paper
Full-text available
A groundwater exploration work in the Tamanrasset region in southern Algeria was started in August 2016 to assess the water reserves in the hydrogeological system related to the Oued Tamanrasset underflow water table which overcomes a volcanic basement. Five (05) electrical resistivity tomography (ERT) surveys were conducted in Tamanrasset area by...
Article
Full-text available
The aquifer of the semi-arid Kairouan plain has been exploited for decades to supply the growing irrigated agriculture and theneed of drinking water. In parallel, the major hydraulic works drastically changed the natural groundwater recharge processes.The continuous groundwater level drop observed since the 1970s naturally raises the question of gr...
Article
Full-text available
Socio-hydrology advanced the field of hydrology by considering humans and their activities as part of the water cycle, rather than as external drivers. Models are used to infer reproducible trends in human interactions with water resources. However, defining and handling water problems in this way may restrict the scope of such modeling approaches....
Chapter
Due to the growing water demand, especially for the agricultural development, the water management in the Grombalia region (NE Tunisia) exploits multiple sources of water. Rainfall is marked by a strong seasonal and interannual variability in time and over space. The regional aquifer has been intensively used for irrigation. Artificial groundwater...
Chapter
Full-text available
ln the previous fifty years, there has been an astounding boom in agricultural groundwater use, improving livelihoods and food security. Nevertheless, these remarkable improvements were not possible without a price to pay: agricultural groundwater use stands as a major threat to both quantity and quality of aquifers. This is particularly emblemati...
Article
A groundwater exploration work in the Tamanrasset region in southern Algeria was started in August 2016 to assess the water reserves in the hydrogeological system related to the Oued Tamanrasset underflow water table which overcomes a volcanic basement. Five (05) electrical resistivity tomography (ERT) surveys were conducted in Tamanrasset area by...
Article
Surface water and groundwater for irrigation are frequently used conjunctively, especially in semiarid and arid regions. Planning conjunctive management involves several difficulties, one of which is adapting irrigation institutions and infrastructure to coordinate the management of multiple water resources. This article focuses on the social and m...
Article
Declining groundwater resources in semi-arid areas are often cited because of anthropization and climate change. This is not the case in Nouakchott (Mauritania) where the water level has risen by 1 to 2 m over the last 40 years in parallel with urban expansion (+1 million inhabitants in 60 years). Using former and new data, primarily water table me...
Article
This essay introduces a collection of articles that explore the future of groundwater-based agriculture in the Mediterranean from an interdisciplinary perspective, in a context of declining water tables due to intensive groundwater use. The imminent crisis that many groundwater economies face due to very rapid and intense global change may have sev...
Article
A comprehensive overview is provided of processes and challenges related to Mediterranean groundwater resources and associated changes in recent decades. While most studies are focused thematically and/or geographically, this paper addresses different stages of groundwater exploitation in the region and their consequences. Examples emphasize the co...
Article
In central Tunisia, near the city of Kairouan, the Merguellil catchment illustrates the multiple forms of the global change affecting Mediterranean water resources. In this semi-arid region, climatic fluctuations have always constrained the water resources, but anthropization has become by far the most influential driver of change in the last centu...
Article
LLe comportement de la nappe côtière de Nouakchott en réponse aux contraintes naturelles et anthropiques a été étudié en combinant deux approches : hydrodynamique (évolution piézométrique durant les dernières décennies) et géochimique (éléments majeurs, bromure et isotopes stables de la molécule d'eau). Les résultats montrent une remontée du niveau...
Article
La problématique de l'eau au Sahara algérien ne date pas d'aujourd'hui : ressources en eau de surface naturellement faibles et provenant exclusivement des crues temporaires et irrégulières des oueds, aquifères parfois restreints à de petits corridors alluviaux dont la structure et la géométrie sont mal connues, rapide développement démographique et...
Article
A groundwater exploration work in the Tamanrasset region in southern Algeria was started in August 2016 to assess the water reserves in the hydrogeological system related to the Oued Tamanrasset underflow water table which overcomes a volcanic basement. Five (05) electrical resistivity tomography (ERT) surveys were conducted in Tamanrasset area by...
Conference Paper
Full-text available
In SW Niger, close to Niamey, a detailed hydrological survey has been developed for the last 25 years over 10 000 km2 by the international experiments Hapex Sahel and AMMA. Quality and consistency of these long-t erm obs ervations allowed assessing the causes and the cons equences of global change in the region. The most original and paradoxical sc...
Article
In recent decades major water developments have led to an agricultural transformation of the Senegal delta both in Senegal and Mauritania. This otherwise, semi-arid region of the Sahel band now has an abundant supply of freshwater all year round mostly used for irrigation and urban water supply, including for the capital cities of the two countries...
Article
The management of groundwater resources is very important in the semiarid Sahel region, which is experiencing rapid urban development. Impacts of urbanization on groundwater resources were investigated in the unconfined aquifer of the Continental Terminal beneath the city of Niamey, Niger, using water level and chemical data. Hydrodynamic and chemi...
Article
L'influence cumulee des amenagements de versants sur les ecoulements en zones semi-arides demeure peu etudiee et comprise a l'echelle de grands bassins versants. En Tunisie centrale, nous etudions les variations de la reponse hydrologique du bassin du Merguellil a l'echelle annuelle et pour 114 evenements entre 1989 et 2010. Sur cette periode, les...
Article
L'influence cumulée des aménagements de versants sur les écoulements en zones semi-arides demeure peu étudiée et comprise a l'échelle de grands bassins versants. En Tunisie centrale, nous étudions les variations de la réponse hydrologique du bassin du Merguellil a l'échelle annuelle et pour 114 évènements entre 1989 et 2010. Sur cette période, les...
Conference Paper
The use of radionuclide tracers to determine the submarine groundwater discharges has been used widely but in areas highly anthropized as the Mar Menor surface water tributaries can carry high concentration of Radon, making very difficult to distinguish the radionuclide origin. In this paper a combined approach was applied in the Mar Menor, a towed...
Conference Paper
Full-text available
In highly anthropized watersheds, surface water tributaries may carry unexpectedly high quantities of radon (222Rn) to surface water masses. Assessing the impact of these additional sources of radionuclides on the spatial repartition of radionuclides is a hard task for submarine groundwater discharge (SGD) investigations. A methodology was tested t...
Article
Full-text available
Study region: The El Haouareb dam (Merguellil catchment) in central Tunisia, which is typical of semi-arid environments. Study focus: Most estimates of evaporation from water bodies located in semi-arid environments suffer from the lack of data, or biased field measurements. It is thus important for hydrologists to assess the relative performance o...
Conference Paper
Full-text available
Situé au SE de l’Espagne, le Campo de Cartagena est un cas emblématique extrême des changements hydrologiques et environnementaux causés par l’utilisation intensive des eaux souterraines pour l’agriculture dans les zones semi-arides du pourtour méditerranéen. Historiquement appelée « désert de Murcie » au début du XXe siècle, cette région est aujo...
Conference Paper
Full-text available
In SW Niger, close to Niamey, a detailed hydrological survey has been developed for the last 20 years (international experiments HAPEX-SAHEL and later AMMA), investigating the distribution of water in atmosphere, surface, soil and aquifers. It covers an area of about 10 000 km2, with a series of imbricated scales of instrumentation, in time and spa...
Article
L’influence cumulée des aménagements de versants sur les écoulements en zones semi-arides demeure peu étudiée et comprise à l’échelle de grands bassins versants. En Tunisie centrale, nous étudions les variations de la réponse hydrologique du bassin du Merguellil à l’échelle annuelle et pour 114 événements entre 1989 et 2010. Sur cette période, les...
Article
L’aquifère du Trarza s’étend sur environ 40 000 km2 dans le Sud-Ouest mauritanien, entre le fleuve Sénégal au Sud, l’Océan Atlantique à l’Ouest et la chaîne métamorphique des Mauritanides au Nord et à l’Est. La nappe libre est contenue dans les sédiments du Continental Terminal et du Quaternaire. Les campagnes de terrain menées entre 2010 et 2012 o...
Article
The development of intense agriculture in semiarid areas modifies intensity and spatial distribution of groundwater recharge by summing irrigation return flow to limited rainfall infiltration. Environmental tracers provide key information, but their interpretation is complicated by more complex groundwater flow patterns. In multilayered aquifers, t...
Article
The Trarza aquifer extends over about 40 000 km(2) in southwestern Mauritania, between the Senegal River in the south, the Atlantic Ocean in the west and the Mauritanides metamorphic chain in the north and east. The Trarza aquifer lies in Continental Terminal and Quaternary sediments. The field investigations conducted between 2010 and 2012 signifi...
Article
Full-text available
A great variety of types of wells and water-lifting devices have been in use through the Sahara and Sahel regions. An analysis of their spatial distribution and evolution through time provides new pieces of information about the origin of their development, often in connection with trade exchanges through the continent. In the Lake Chad basin, some...
Article
Full-text available
Radiocarbon decay is rarely used to assess the residence time of modern groundwater due to the low resolution of its long half-life in comparison to the expected range of ages. Nonetheless, the modern 14C peak induced by the nuclear bomb tests traces efficiently the impacts of recent human activities on groundwater recharge, as well as for tritium....
Article
Full-text available
In arid and semi-arid regions, the groundwater overexploitation caused drawdown in piezometric levels and a degradation of chemical water quality. That is why the groundwater monitoring needs a good comprehension of the hydrogeological aquifer properties. This is specially the case of Zéramdine–Béni Hassen deep aquifer (east-central Tunisia). Seism...
Data
Full-text available
The development of intense agriculture in semiarid areas modifies intensity and spatial distribution of groundwater recharge by summing irrigation return flow to limited rainfall infiltration. Environmental tracers provide key information, but their interpretation is complicated by more complex groundwater flow patterns. In multilayered aquifers, t...
Article
L'influence cumulée des aménagements de conservation des eaux et des sols (CES) à l'échelle de grands bassins versants demeure peu étudiée et comprise, malgré leur développement important dans de nombreuses zones semi-arides. Une des complexités de l'analyse réside dans la difficulté à différencier l'effet des nombreux processus anthropiques et cli...
Article
Full-text available
Le système aquifère Ilaló – Cumbayá-Tumbaco en Equateur a alimenté la population des vallées proches de Quito durant trois décennies. Depuis 2006, avec l'analyse systématique de l'arsenic, il a été détecté des teneurs supérieures à la norme (>10 mg/l). L'étude générale a l'objectif de comprendre le fonctionnement et les processus qui régissent le s...
Article
Despite small reservoirs becoming increasingly widespread across many semi-arid regions, their cumulative influence in large catchments remains poorly understood. Part of the difficulty lies in distinguishing their effect over concurrent human and climatic processes which also affect runoff. In the Merguellil catchment, in semi-arid central Tunisia...
Article
Radiocarbon decay is rarely used to assess the residence time of modern groundwater due to the low resolution of its long half-life in comparison to the expected range of ages. Nonetheless, the modern ¹⁴ C peak induced by the nuclear bomb tests traces efficiently the impacts of recent human activities on groundwater recharge, as well as for tritium...
Article
Full-text available
Despite the Sahelian drought of the 1970s-1990s, the unconfined aquifer in southwest Niger exhibits a multidecadal increase in groundwater reserves. Recent changes in land surface conditions have enhanced runoff and thus indirect groundwater recharge below endorheic ponds. This paper presents a model-based investigation of surface runoff and ground...
Article
In arid central Australia, the ∼1.14 M km2 endorheic Lake Eyre Basin (LEB) experiences sporadic floods, and contains saline shallow groundwater. In this basin, where on-ground physical and chemical data are very sparse, new observations of major ion chemistry, stable isotopes (δ2H, δ18O, δ13C), radiogenic isotopes (3H, 14C), and remote sensing (MOD...
Article
Full-text available
Despite the Sahelian drought of the 1970s–1990s, the unconfined aquifer in southwest Niger exhibits a multidecadal increase in groundwater reserves. Recent changes in land surface conditions have enhanced runoff and thus indirect groundwater recharge below endorheic ponds. This paper presents a model-based investigation of surface runoff and ground...
Article
As in many other semi-arid regions, the Plio-quaternary aquifer of the eastern coast of Cap Bon peninsula (NE Tunisia) shows a parallel increase in overexploitation and mineralization of groundwater resources and so the water quality is deteriorating. Different methods using geochemistry (ions Na+, Cl−, Ca2+, Mg2+, Br−) and stable isotopes (18O, 2H...
Article
The Merguellil catchment in central Tunisia is typical of the south Mediterranean environment, with large climatic variability and big recent changes in vegetation and soil conditions. In its middle, a big dam, built in 1989 over the El Haouareb fractured-limestone aquifer, completely modified the regional water flows. The dam reservoir and the El...
Poster
The groundwater chemistry in the local vicinity of the city of Niamey was investigated in order to identify the origin of the groundwater mineralization and, in particular, to elucidate the impact of urbanization on the groundwater resources. Sources of pollution of concern in the urban area are solid waste and material deposited on the ground and...
Article
Like all other Mediterranean countries, Tunisia provides multiple examples of groundwater degradation due to its overexploitation. This is especially the case in the Zéramdine-Mahdia-Jébéniana region (central east Tunisia), where recent measurements revealed an important piezometric drop in the Miocene aquifers. Through hydrodynamic and hydrochemic...
Article
Full-text available
Abstr act Like all other Med iterran ean countr ies, Tunisia pro vides multiple examples of groundwater degradation du e to its overexp loitatio n. Th is is es pecially the case in the Zeramdine-Mahdia-Jebeniana region (cen tral east Tunisia) , where recent measurements revealed an import ant piezometric drop in the M iocene aquifers. Th rough hydr...