Gil Mahe

Gil Mahe
Institute of Research for Development | IRD · 050 - HydroSciences Montpellier (HSM)

PhD HDR
North African synthesis on the impact of dams on the coastal retreat by study of sediment transport in streams and cores

About

487
Publications
545,519
Reads
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Introduction
My overall goal is to improve knowledge to answer to development stakes through a scientific approach in the field of hydrology, climate, water resources and environmental issues. This I try to achieve through: - increase the collaborations at the regional scale in the Mediterranean, and create a regional team in North Africa for the study of large river basins hydrology under climate and human changes - promote studies dealing with the impact of large basins management on the sediment fluxes to the sea and coastal impacts. I strongly support the development of partnerships at the continental scale to improve the visibility of African scientists in the international organisations and raise interest for the hydrology of tropical and semi arid countries.
Additional affiliations
December 2020 - present
Institut National des Sciences et Technologies de la Mer
Position
  • Research Director
September 2014 - present
Université de Montpellier
Position
  • Research Director
September 2013 - September 2017
Faculty of Sciences, University Mohammed V
Position
  • Master's Student
Description
  • Hydroclimatology, 26 hours
Education
September 2005 - September 2006
University of Montpellier
Field of study
  • Earth Sciences
September 1989 - September 1992
Université Paris-Sud 11
Field of study
  • Earth Sciences
September 1986 - September 1987
Université Paris-Sud 11
Field of study
  • Hydrogeology

Publications

Publications (487)
Conference Paper
Full-text available
Maghreb countries are strongly impacted by floods, causing twice as many deaths as in southern European countries in recent decades. However, due to the lack of data accessibility, there are no studies to analyze whether the frequency or intensity of floods are changing at the regional scale. In this work, a recent database of daily river discharge...
Conference Paper
Maghreb countries are strongly impacted by floods, causing twice as many deaths as in southern European countries in recent decades. However, due to the lack of data accessibility, there are no studies to analyze whether the frequency or intensity of floods are changing at the regional scale. In this work, a recent database of daily river discharge...
Article
Full-text available
Understanding hydrological variability is of crucial importance for water resource management in sub-Saharan Africa (SSA). While existing studies typically focus on individual river basins, and suffer from incomplete records, this study provides a new perspective of trends and variability in hydrological flood and drought characteristics (frequency...
Conference Paper
Full-text available
Zone d'agriculture pluviale conventionnelle, le bassin de la Comoé subit des modifications environnementales et climatiques, depuis les décennies 1970 et 1980. Cette recherche évalue l'impact des changements climatiques sur l'évolution des conditions hydriques de production ; l'analyse fréquentielle des saisons culturales par simulation du bilan hy...
Conference Paper
Full-text available
Sub-Saharan Africa is affected by a high-level of temporal and spatial variability in climate, with large impacts on water resources, human lives and economies, notably through hydrological extremes, such as floods and droughts. Using a newly reconstructed 65-year daily streamflow dataset of over 600 stations distributed throughout sub-Saharan Afri...
Conference Paper
Full-text available
Sub-Saharan Africa is affected by a high-level of temporal and spatial climate variability, with large impacts on water resources, human lives and economies, notably through hydrological extremes, such as floods and droughts. Using a newly reconstructed 65-year daily streamflow dataset of over 600 stations distributed throughout sub-Saharan Africa,...
Conference Paper
Full-text available
Climate change, as one of the most significant challenges that humans currently face, is defined as a shift in climate patterns in response to increasing greenhouse gas emissions in the atmosphere. Notably, climate change has been associated with global warming temperature, regional changes in rainfall patterns and extreme events. Such changes in c...
Article
Full-text available
Abstract. Water erosion is one of the major causes of soil degradation in the world. Among the most negative effects of water erosion is the accumulation of sedimentation in dam reservoirs, leading to a loss of their water storage potential and agro-pedological damage. In the northwest of Morocco, the Bouregreg watershed experiences soil losses eve...
Article
Full-text available
Climate change, variability and anthropogenic forcings such as land use change are the main forcings of river discharge variability. However, an understanding of their simultaneous impacts on river discharge remains limited in some parts of the world. To shed light on this issue, the objective of this article is to investigate the effects of rainfa...
Article
Full-text available
Sediment transport in basins disturbs the ecological systems of the water bodies and leads to reservoir siltation. Its evaluation is crucial for managing water resources. The practical application of the process-based model can confront some limitations noticed in the lower accuracy during the validation process due to the lack of reliable physical...
Chapter
Full-text available
This chapter describes the variability of rainfall and river discharges in the Ogooué River Basin (ORB) in recent decades (since 1940). Due to its location crossing the Equator, the ORB receives abundant precipitation, which maintains one of the world's best‐preserved ecosystems. In contrast to neighboring forest basins that have been severely degr...
Data
Gridded data, monthly flow rates, GIS layers hydro climatic data sets of West and Central African watershed gathering optimized parameters for hydrological modeling and improving the various studies of impacts on water resources. The general architecture of the directories and files are as follow : Main Directory: watershed name. The main directory...
Chapter
Full-text available
Soil degradation is a serious and extensive problem in many areas in Algeria. Information on soil loss is essential to support agricultural productivity and natural resource management. In this study, remote sensing and GIS are used in order to map and assess water erosion in the Wadi Cheliff basin. The study area is characterized by a great irregu...
Chapter
Full-text available
Ce chapitre décrit la variabilité des précipitations et des débits des rivières dans le bassin de l'Ogooué (ORB) au cours des dernières décennies (depuis 1940). En raison de sa situation géographique, traversant l'équateur, l'ORB reçoit des précipitations abondantes qui maintiennent l'un des écosystèmes les mieux préservés au monde. Contrairement a...
Chapter
The latest work on the main African rivers on the Atlantic coast has made it possible to subdivide the multi‐year streamflow records into several homogeneous phases. The year 1970 seems to mark, for both West and Central Africa, the major hydroclimatic event of the 20th century, heralding its main period of deficit flow. For the first time, this ar...
Chapter
Les derniers travaux concernant les principaux fleuves africains de la façade atlantique ont permis de subdiviser les chroniques pluriannuelles de leurs écoulements en plusieurs phases homogènes. L'année 1970 semble marquer à la fois pour l'Afrique Occidentale comme pour l'Afrique Centrale l'accident hydroclimatique majeur du XX ème siècle annonçan...
Data
Gridded data, monthly flow rates, GIS layers hydro climatic data sets of West and Central African watershed gathering optimized parameters for hydrological modeling and improving the various studies of impacts on water resources. The general architecture of the directories and files are as follow : Main Directory: watershed name. The main directory...
Data
Gridded data, monthly flow rates, GIS layers hydro climatic data sets of West and Central African watershed gathering optimized parameters for hydrological modeling and improving the various studies of impacts on water resources. The general architecture of the directories and files are as follow : Main Directory: watershed name. The main directory...
Presentation
Full-text available
Au Nord de l'Algérie, le bassin versant de l‘Oued Cheliff est fortement affecté par une baisse des débits depuis les années 1970. La diminution des précipitations en est la cause principale. Le développement de modèles efficaces est plus que nécessaire pour une meilleure évaluation des potentialités et des risques à court, à moyen et à long terme...
Article
Full-text available
This paper investigates links between rainfall variability in the Ogooué River Basin (ORB) and El Niño Southern Oscillation (ENSO) in the Pacific Ocean. Recent hydroclimatology studies of the ORB and surrounding areas resulting in contrasting conclusions about links between rainfall variability and ENSO. Thus, to make the issue clearer, this study...
Article
Full-text available
Le Bouregreg est le deuxième fleuve du Maroc. Il draine les eaux du centre du Maroc, du Moyen Atlas à l'Atlantique, qui sont stockées dans la retenue du barrage Sidi Mohamed Ben Abdellah créé en 1974 et situé à proximité de Rabat. Sa fonction exclusive est l'alimentation en eau potable pour les besoins individuels et industriels de 6 millions d'hab...
Article
Full-text available
Le bassin versant exoréique de l'Oued Ambouli situé au sud-est de la République de Djibouti, s'étend sur plus de 794 km2 soit 3.5 % de la surface du pays. Il est le plus grand bassin versant du district de Djibouti. Cet oued est soumis à des crues rares et brèves qui causent de lourds dégâts en vies humaines et économiques, accentués par l'expansio...
Article
Full-text available
The FRIEND-Water program (FWP) is the oldest and the most transverse program (i.e. Flagship Initiative) within the Hydrological Intergovernmental Program (IHP) from UNESCO. FRIEND means “Flow Regimes from International and Experimental Network Data”. The FWP is dedicated to allow large communities of hydrologists and associated disciplines to colla...
Article
Full-text available
Northern African beaches are among the most vulnerable areas under the extreme climate change hazard. Mainly sedimentary low-lying platform, the coasts are supplied by terrestrial yields, which are increasingly interrupted by dams. Unfortunately, the sediment fluxes are rarely measured and monitored, so that it is quite impossible today to assess t...
Article
Full-text available
La sécheresse observée en Afrique tropicale vers la fin des années 1960, a également affecté le bassin de la Bénoué en Afrique centrale, avec une persistance remarquable qui s'est répercutée sur les écoulements. Les ruptures à la baisse ont été mises en évidence dans les séries hydropluviométriques de ce bassin au pas de temps annuel en 1970–1971 (...
Article
Full-text available
L'objectif de cet article est de faire une évaluation des tendances récentes des grandeurs hydroclimatiques dans le bassin de l'Ogooué en contexte de changement climatique. Pour cela, les données de pluies et de débits de ce bassin ont été analysées au moyen du test de Pettitt. Les résultats de cette étude révèlent une diminution statistiquement si...
Article
Full-text available
This work is dedicated to the study of the spatio-temporal variability of climate in Morocco by the analysis of rainfall (gridded and gauged data) and runoff. The wavelet analysis method has been used in this study to compare the rainfall and runoff series and to show the major discontinuities identified in 1970, 1980, and 2000. Several modes of va...
Presentation
Full-text available
Project for the implementation of an observatory of the coastal area of the North Gulf of Tunis, Ghar el Melh lagoon, which experiences a rapid degradation of its environnemental conditions, beach retreat, water quality, marine submersion
Article
In this study, an assessment of similarity relationships across runoff measurements at various spatial scales was carried in a typical Sahelian landscape, under semi-arid climate in northern Burkina Faso (west African Sahel). The scales of observations considered are the plot scale (1 m², 50 m², 150 m²) and the sub-catchment scale (6.1 ha, 33.8 ha)...
Presentation
. The prediction of flows upstream of the SMBA dam was carried out on the basis of RCA4 regional climate simulations of precipitation and historical temperatures over the period 1981-2005 and then projected for the near future 2025-2050 with an assessment of two Representative Concentration Pathway RCP4.5 and RCP 8.5.
Article
Full-text available
West Africa exhibits decadal patterns in the behaviour of droughts and floods, creating challenges for effective water resources management. Proposed drivers of prolonged shifts in hydrological extremes include the impacts of land-cover change and climate variability in the region. However, while future land-degradation or land-use are highly unpre...
Article
Full-text available
Many studies have been undertaken on climate variability in West Africa since the drastic drought of 1970s. These studies rely in many cases on different baseline periods chosen with regard to the reference periods defined by the World Meteorological Organization. A method is developed in this study to determine a stationary baseline period for rai...
Article
Recent reductions of sediment transport are observed in Bouregreg River and estuary close to Rabat city in Morocco. The cause of this evolution in sediment transport which may be due to human (dam, pollution), climate variability and natural events has been investigated from a paleo-hydrological approach. Sedimentological and geochemical analyses o...
Conference Paper
Full-text available
Africa is affected by a high-level of temporal and spatial variability in climate, with large impacts on water resources, human lives and economies. Due to data scarcity, the impact of multi-year climate variations on hydrological variability and extremes, i.e. flood and drought, as well as how catchment properties could modulate those impacts, are...
Article
Full-text available
The African continent is probably the one with the lowest density of hydrometric stations currently measuring river discharge despite the fact that the number of operating stations was quite important until the 1970s. This new African Database of Hydrometric Indices (ADHI) provides a wide range of hydrometric indices and hydrological signatures com...
Article
Full-text available
The objective of this study is to investigate the evolution of rainfall and flow in the Bouregreg watershed, and to identify the most vulnerable regions to climate change over a period of 36 years from 1977 to 2013. Results show significant variations between these sub-regions in term of monthly flows and monthly regimes. January and February rainf...
Article
Full-text available
Most tropical and Mediterranean areas, landscapes, soils, and territories are experiencing new vulnerabilities, facing global warming [...]
Article
Full-text available
The arid coasts of North Africa, extending over 4633 km from the Gulf of Tunis to the Nile Delta, are undergoing pronounced shoreline retreats and coastal floodings that are reported as a consequence of the ongoing sea level rise resulting from global warming. Of particular interest are the abnormal shoreline dynamics for deltaic and sandy beaches,...
Conference Paper
Full-text available
The Cheliff watershed has a considerable expanse from east to west, beginning with M'Sila to Mostaganem, as seen from this expanse, with great climatic, topographic, geological diversity etc., hence the magnitude of the solid transport phenomenon and the resulting siltation. The scarcity of the region's water resource (average 450 mm·y-1), hence th...
Data
Gridded data, monthly flow rates, GIS layers data sets of West and Central African watershed gathering optimized parameters for hydrological modeling and improving the various studies of impacts on water resources. The general architecture of the directories and files are as follow : Main Directory: watershed name. The main directory contains x s...
Article
Full-text available
An analysis of rainfall and hydrometric regimes was carried out over the period from 1968 to 2013 on the Cheliff basin situated in the west and the Medjerda basin in the east of Algeria. The Mann–Kendal and Pettitt tests have shown significant downward trends for rainfall, about 30% for the Cheliff basin, and 36% for the Medjerda basin, and about 6...
Data
Gridded data, monthly flow rates, GIS layers data sets of West and Central African watershed gathering optimized parameters for hydrological modeling and improving the various studies of impacts on water resources. The general architecture of the directories and files are as follow : Main Directory: watershed name. The main directory contains x sub...
Preprint
Full-text available
The African continent is probably the one with the lowest density of hydrometric stations currently measuring river discharge, despite the fact that the number of operating stations was quite important until the 70s. This new African Database of Hydrometric Indices (ADHI) is compiling data from different sources carefully checked for quality contro...
Article
Full-text available
The Rambla de Algeciras lake in Murcia is a reservoir for drinking water and contributes to the reduction of flooding. With a semi-arid climate and a very friable nature of the geological formations at the lakeshore level, the emergence and development of bank gullies is favored and poses a problem of silting of the dam. A study was conducted on th...
Article
Full-text available
A large share of surface water resources in Sahelian countries originates from Guinea's Fouta Djallon highlands, earning the area the name of "the water tower of West Africa". This paper aims to investigate the recent dynamics of the Fouta Djallon's hydrological functioning. The evolution of the runoff and depletion coefficients are analyzed as wel...
Article
Full-text available
Climate change and anthropization are major drivers of river flows variability. However, understanding their simultaneous impact on discharges is limited. As a contribution to address this limitation, the objective of this study is to assess the impact of climate change and anthropization on the discharges of two watersheds of Central Africa (Nyong...
Article
Full-text available
Although the Congo Basin is still one of the least studied river basins in the world, this paper attempts to provide a multidisciplinary but non-exhaustive synthesis on the general hydrology of the Congo River by highlighting some points of interest and some particular results obtained over a century of surveys and scientific studies. The Congo Riv...
Conference Paper
Full-text available
The purpose of this study is to identify homogeneous rainfall regions and to study the spatial and temporal variability of rainfall in the Cheliff basin using the regional vector method and the statistical approach (Pettitt test, Lee Heghinian test and Hubert segmentation) and the geostatistic approach (inverse distance weight-ing method). In terms...
Conference Paper
Full-text available
The Bouregreg watershed is located to the northwestern center of Morocco, characterized by a semi-arid climate. It covers a total area of approximately 10 000 km 2. This basin is a very sensitive area to water erosion. This causes the degradation of its vegetation cover and its land. The most sensitive and poorly protected soils erode much more eas...
Conference Paper
Full-text available
The Ouémé watersheds at Bétérou and Bonou has been recently facing increased sensitivity to extreme hydroclimatic phenomena that occurred by flooding or drought events. In the same time, the population growth and the related socioeconomic activities increased the pressure state on water resources. In this context, hydrological modeling is an import...
Conference Paper
Full-text available
The world's freshwater environment is changing rapidly and facing unprecedented pressures. A growing global population and economic development have led to increasing demands on water resources and water management. The impact of climate change and intensive anthropogenic activities is now posing a great threat on the hydrological cycle leading to...
Article
Full-text available
The Paris Climate Agreements and Sustainable Development Goals, signed by 197 countries, present agendas and address key issues for implementing multi-scale responses for sustainable development under climate change—an effort that must involve local, regional, national, and supra-national stakeholders. In that regard, Continental Carbon Sequestrati...
Article
The current study focuses on the issue of the decrease in sediment discharge to the Mediterranean Sea by the largest river in Algeria, the Wadi Cheliff (i.e. Cheliff River). This study clarifies the effect of climatic and anthropogenic factors on the changes in the sedimentary dynamics of the Cheliff River discharging to the sea. The data used (rai...
Article
Full-text available
The current study focuses on the issue of the decrease in sediment discharge to the Mediterranean Sea by the largest river in Algeria, the Wadi Cheliff (i.e. Cheliff River). This study clarifies the effect of climatic and anthropogenic factors on the changes in the sedimentary dynamics of the Cheliff River discharging to the sea.
Article
Full-text available
This article is a French version of my article entitled "Climatic and anthropogenic impacts on the decrease of sediment discharge to the Mediterranean coast from the largest river of Maghreb." published in the International Journal of Sediment Research.
Article
Full-text available
A limited number of studies have been conducted in Morocco to estimate dams siltation rate based on suspended solids concentration (SSC) field measurements. The present article provides an evaluation of the siltation rate through an inventory of field measurements data which has been collected upstream of Sidi Mohamed Ben Abdellah (SMBA) Dam reserv...
Article
Full-text available
The evaluation and quantification of solids transport in Morocco often uses the Universal Soil Loss Model (USLE) and the revised version RUSLE, which presents a calibration difficulty. In this study, we apply the MUSLE model to predict solid transport, for the first time on a large river basin in the Kingdom, calibrated by two years of solid transp...
Article
Full-text available
More often daily climate data have been used in hydrological models to estimate flood flows in small data scarce urban and rural catchments where flow peaking and recession are quick within short periods of few hours. This study assesses magnitudes of error of using daily climate data to simulate flood flow hydrographs of a small urban river catchm...