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Dr. Gil Mahe
IRD, UMR HSM IRD/Univ Montpellier, France

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0 Hydrology
0 environment
0 Hydrological Modelling
0 Human impact

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Review article
Published: 29 May 2021 in Journal of African Earth Sciences
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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 of slackwater flood deposits are used to assess the impact of a dam installed in 1974 and the climate change on the evolution of sediment transport during about 60 years. Higher accumulation rate of about 3,64 cm/year is observed between 1950 and 1978, whereas it was much lower about 0,41 cm/year between 1990 and 2017. This strong decrease in sediment rate appears much more due to dam effect than to climate change.

ACS Style

Rajae El. Aoula; Nadia Mhammdi; Laurent Dezileau; Gil Mahe; Alexander S. Kolker. Fluvial sediment transport degradation after dam construction in North Africa. Journal of African Earth Sciences 2021, 182, 104255 .

AMA Style

Rajae El. Aoula, Nadia Mhammdi, Laurent Dezileau, Gil Mahe, Alexander S. Kolker. Fluvial sediment transport degradation after dam construction in North Africa. Journal of African Earth Sciences. 2021; 182 ():104255.

Chicago/Turabian Style

Rajae El. Aoula; Nadia Mhammdi; Laurent Dezileau; Gil Mahe; Alexander S. Kolker. 2021. "Fluvial sediment transport degradation after dam construction in North Africa." Journal of African Earth Sciences 182, no. : 104255.

Journal article
Published: 26 March 2021 in Geographia Polonica
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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 rainfall amounts are the most affected by the reduction of rainfall since the drought started end of the 1970’s, inducing a reduction of flows at all hydrological stations mainly since 1979. The year 1996 shows very high precipitations over all sub-basins, and also separates two periods with different rainfall time series variations according to two regions over the basin: the region of the Tsalat sub-basin in the Southeast wet and mountainous area (Middle Atlas) shows a durable decrease of rainfall compared to the Ain Loudah sub-basin in the Center-West semi-arid plateau area.

ACS Style

Rajae El Aoula; Gil Mahe; Nadia Mhammdi; Abdellatif Ezzahouani; Ilias Kacimi; Kenza Khomsi. Evolution of the hydrological regime in relation to climate change: Case of the Bouregreg River basin, Morocco. Geographia Polonica 2021, 94, 131 -147.

AMA Style

Rajae El Aoula, Gil Mahe, Nadia Mhammdi, Abdellatif Ezzahouani, Ilias Kacimi, Kenza Khomsi. Evolution of the hydrological regime in relation to climate change: Case of the Bouregreg River basin, Morocco. Geographia Polonica. 2021; 94 (1):131-147.

Chicago/Turabian Style

Rajae El Aoula; Gil Mahe; Nadia Mhammdi; Abdellatif Ezzahouani; Ilias Kacimi; Kenza Khomsi. 2021. "Evolution of the hydrological regime in relation to climate change: Case of the Bouregreg River basin, Morocco." Geographia Polonica 94, no. 1: 131-147.

Editorial
Published: 14 February 2021 in Water
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Most tropical and Mediterranean areas, landscapes, soils, and territories are experiencing new vulnerabilities, facing global warming

ACS Style

Gil Mahé; Luc Descroix; Alain Laraque; Olivier Ribolzi; Guillaume Lacombe. Special Issue “Multiscale Impacts of Anthropogenic and Climate Changes on Tropical and Mediterranean Hydrology”. Water 2021, 13, 491 .

AMA Style

Gil Mahé, Luc Descroix, Alain Laraque, Olivier Ribolzi, Guillaume Lacombe. Special Issue “Multiscale Impacts of Anthropogenic and Climate Changes on Tropical and Mediterranean Hydrology”. Water. 2021; 13 (4):491.

Chicago/Turabian Style

Gil Mahé; Luc Descroix; Alain Laraque; Olivier Ribolzi; Guillaume Lacombe. 2021. "Special Issue “Multiscale Impacts of Anthropogenic and Climate Changes on Tropical and Mediterranean Hydrology”." Water 13, no. 4: 491.

Journal article
Published: 22 October 2020 in Water
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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 well as their correlations with the rainfall and vegetation cover. The latter is described at three different space scales and with different methods. Twenty-five years after the end of the 1968–1993 major drought, annual discharges continue to slowly increase, nearly reaching a long-term average, as natural reservoirs which emptied to sustain streamflows during the drought have been replenishing since the 1990s, explaining the slow increase in discharges. However, another important trend has been detected since the beginning of the drought, i.e., the increase in the depletion coefficient of most of the Fouta Djallon upper basins, as a consequence of the reduction in the soil water-holding capacity. After confirming the pertinence and significance of this increase and subsequent decrease in the depletion coefficient, this paper identifies the factors possibly linked with the basins’ storage capacity trends. The densely populated areas of the summit plateau are also shown to be the ones where vegetation cover is not threatened and where ecological intensification of rural activities is ancient.

ACS Style

Luc Descroix; Bakary Faty; Sylvie Paméla Manga; Ange Bouramanding Diedhiou; Laurent A. Lambert; Safietou Soumaré; Julien Andrieu; Andrew Ogilvie; Ababacar Fall; Gil Mahé; Fatoumata Binta Sombily Diallo; Amirou Diallo; Kadiatou Diallo; Jean Albergel; Bachir Alkali Tanimoun; Ilia Amadou; Jean-Claude Bader; Aliou Barry; Ansoumana Bodian; Yves Boulvert; Nadine Braquet; Jean-Louis Couture; Honoré Dacosta; Gwenaelle Dejacquelot; Mahamadou Diakité; Kourahoye Diallo; Eugenia Gallese; Luc Ferry; Lamine Konaté; Bernadette Nka Nnomo; Jean-Claude Olivry; Didier Orange; Yaya Sakho; Saly Sambou; Jean-Pierre Vandervaere. Are the Fouta Djallon Highlands Still the Water Tower of West Africa? Water 2020, 12, 2968 .

AMA Style

Luc Descroix, Bakary Faty, Sylvie Paméla Manga, Ange Bouramanding Diedhiou, Laurent A. Lambert, Safietou Soumaré, Julien Andrieu, Andrew Ogilvie, Ababacar Fall, Gil Mahé, Fatoumata Binta Sombily Diallo, Amirou Diallo, Kadiatou Diallo, Jean Albergel, Bachir Alkali Tanimoun, Ilia Amadou, Jean-Claude Bader, Aliou Barry, Ansoumana Bodian, Yves Boulvert, Nadine Braquet, Jean-Louis Couture, Honoré Dacosta, Gwenaelle Dejacquelot, Mahamadou Diakité, Kourahoye Diallo, Eugenia Gallese, Luc Ferry, Lamine Konaté, Bernadette Nka Nnomo, Jean-Claude Olivry, Didier Orange, Yaya Sakho, Saly Sambou, Jean-Pierre Vandervaere. Are the Fouta Djallon Highlands Still the Water Tower of West Africa? Water. 2020; 12 (11):2968.

Chicago/Turabian Style

Luc Descroix; Bakary Faty; Sylvie Paméla Manga; Ange Bouramanding Diedhiou; Laurent A. Lambert; Safietou Soumaré; Julien Andrieu; Andrew Ogilvie; Ababacar Fall; Gil Mahé; Fatoumata Binta Sombily Diallo; Amirou Diallo; Kadiatou Diallo; Jean Albergel; Bachir Alkali Tanimoun; Ilia Amadou; Jean-Claude Bader; Aliou Barry; Ansoumana Bodian; Yves Boulvert; Nadine Braquet; Jean-Louis Couture; Honoré Dacosta; Gwenaelle Dejacquelot; Mahamadou Diakité; Kourahoye Diallo; Eugenia Gallese; Luc Ferry; Lamine Konaté; Bernadette Nka Nnomo; Jean-Claude Olivry; Didier Orange; Yaya Sakho; Saly Sambou; Jean-Pierre Vandervaere. 2020. "Are the Fouta Djallon Highlands Still the Water Tower of West Africa?" Water 12, no. 11: 2968.

Journal article
Published: 01 October 2020 in Water
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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 these lakeshores to estimate the sediment input from the bank gullies. In 2018, three gullies of different types were the subject of three UAV photography missions to model in high resolution their low topographic change, using the SfM-MVS photogrammetry method. The combination of two configurations of nadir and oblique photography allowed us to obtain a complete high-resolution modeling of complex bank gullies with overhangs, as it was the case in site 3. To study annual lakeshore variability and sediment dynamics we used LiDAR data from the PNOA project taken in 2009 and 2016. For a better error analysis of UAV photogrammetry data we compared spatially variable and uniform uncertainty models, while taking into account the different sources of error. For LiDAR data, on the other hand, we used a spatially uniform error model. Depending on the geomorphology of the gullies and the configuration of the data capture, we chose the most appropriate method to detect geomorphological changes on the surfaces of the bank gullies. At site 3 the gully topography is complex, so we performed a 3D distance calculation between point clouds using the M3C2 algorithm to estimate the sediment budget. On sites 1 and 2 we used the DoD technique to estimate the sediment budget as it was the case for the LiDAR data. The results of the LiDAR and UAV data reveal significant lakeshore erosion activity by bank gullies since the annual inflow from the banks is estimated at 39 T/ha/year.

ACS Style

Radouane Hout; Véronique Maleval; Gil Mahe; Eric Rouvellac; Rémi Crouzevialle; Fabien Cerbelaud. UAV and LiDAR Data in the Service of Bank Gully Erosion Measurement in Rambla de Algeciras Lakeshore. Water 2020, 12, 2748 .

AMA Style

Radouane Hout, Véronique Maleval, Gil Mahe, Eric Rouvellac, Rémi Crouzevialle, Fabien Cerbelaud. UAV and LiDAR Data in the Service of Bank Gully Erosion Measurement in Rambla de Algeciras Lakeshore. Water. 2020; 12 (10):2748.

Chicago/Turabian Style

Radouane Hout; Véronique Maleval; Gil Mahe; Eric Rouvellac; Rémi Crouzevialle; Fabien Cerbelaud. 2020. "UAV and LiDAR Data in the Service of Bank Gully Erosion Measurement in Rambla de Algeciras Lakeshore." Water 12, no. 10: 2748.

Journal article
Published: 29 September 2020 in Water
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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 and Ntem) over a recent period. For this, the hydropluviometric data of the watersheds concerned were analyzed using the Pettitt test. Similarly, the dynamics of the main land use modes (LUM) have been assessed, through classifications obtained from the processing of Landsat satellite images of the watersheds studied on two dates. The results of this study show that in Central Africa, annual discharges have decreased significantly since the 1970s, and yet the decline in annual rainfall does not become significant until the 2000s. The discharges of the rainy seasons (spring and autumn) recorded the most important changes, following variations in the rainfall patterns of the dry seasons (winter and summer) that precede them. Winters experienced a significant decrease in precipitation between the 1970s and 1990s, which caused a drop in spring flows. Their rise, which began in the 2000s, is also accompanied by an increase in spring flows, which nevertheless seems rather slight in the case of the Nyong. Conversely, between the 1970s and 1990s, there was a joint increase in summer rainfall and autumn flows. A decrease of summer rainfall was noted since the 2000s, and is also noticeable in autumn flows. Maximum flows have remained constant on the Nyong despite the slight drop in rainfall. This seems to be the consequence of changes in land use patterns (diminution of forest and increasing of impervious areas). The decrease in maximums flows noted on the Ntem could be linked to the slight drop in precipitation during the rainy seasons that generates it. Factors such as the general decrease in precipitation during the winter and the reduction in the area occupied by water bodies could justify the decrease in minimum flows observed in the two watersheds. These findings would be vital to enhance water management capabilities in the watersheds concerned and in the region. They can also give some new elements to study and understand the seasonal variation and fresh water availability in downstream, estuaries and coastal areas of the regional rivers.

ACS Style

Valentin Brice Ebodé; Gil Mahé; Jean Guy Dzana; Joseph Armathé Amougou. Anthropization and Climate Change: Impact on the Discharges of Forest Watersheds in Central Africa. Water 2020, 12, 2718 .

AMA Style

Valentin Brice Ebodé, Gil Mahé, Jean Guy Dzana, Joseph Armathé Amougou. Anthropization and Climate Change: Impact on the Discharges of Forest Watersheds in Central Africa. Water. 2020; 12 (10):2718.

Chicago/Turabian Style

Valentin Brice Ebodé; Gil Mahé; Jean Guy Dzana; Joseph Armathé Amougou. 2020. "Anthropization and Climate Change: Impact on the Discharges of Forest Watersheds in Central Africa." Water 12, no. 10: 2718.

Review
Published: 18 September 2020 in Water
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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 River is especially marked by its hydrological regularity only interrupted by the wet decade of 1960, which is its major anomaly over nearly 120 years of daily observations. Its interannual flow is 40,500 m3 s−1. This great flow regularity should not hide important spatial variations. As an example, we can cite the Ubangi basin, which is the most northern and the most affected by a reduction in flow, which has been a cause for concern since 1970 and constitutes a serious hindrance for river navigation. With regard to material fluxes, nearly 88 × 106 tonnes of material are exported annually from the Congo Basin to the Atlantic Ocean, composed of 33.6 × 106 tonnes of TSS, 38.1 × 106 tonnes of TDS and 16.2 × 106 tonnes of DOC. In this ancient flat basin, the absence of mountains chains and the extent of its coverage by dense rainforest explains that chemical weathering (10.6 t km−2 year−1 of TDS) slightly predominates physical erosion (9.3 t km−2 year−1 of TSS), followed by organic production (4.5 t km−2 year−1 of DOC). As the interannual mean discharges are similar, it can be assumed that these interannual averages of material fluxes, calculated over the longest period (2006–2017) of monthly monitoring of its sedimentology and bio-physical-chemistry, are therefore representative of the flow record available since 1902 (with the exception of the wet decade of 1960). Spatial heterogeneity within the Congo Basin has made it possible to establish an original hydrological classification of right bank tributaries, which takes into account vegetation cover and lithology to explain their hydrological regimes. Those of the Batéké plateau present a hydroclimatic paradox with hydrological regimes that are among the most stable on the planet, but also with some of the most pristine waters as a result of the intense drainage of an immense sandy-sandstone aquifer. This aquifer contributes to the regularity of the Congo River flows, as does the buffer role of the mysterious “Cuvette Centrale”. As the study of this last one sector can only be done indirectly, this paper presents its first hydrological regime calculated by inter-gauging station water balance. Without neglecting the indispensable in situ work, the contributions of remote sensing and numerical modelling should be increasingly used to try to circumvent the dramatic lack of field data that persists in this basin.

ACS Style

Alain Laraque; Guy D. Moukandi N’Kaya; Didier Orange; Raphael Tshimanga; Jean Marie Tshitenge; Gil Mahé; Cyriaque R. Nguimalet; Mark A. Trigg; Santiago Yepez; Georges Gulemvuga. Recent Budget of Hydroclimatology and Hydrosedimentology of the Congo River in Central Africa. Water 2020, 12, 2613 .

AMA Style

Alain Laraque, Guy D. Moukandi N’Kaya, Didier Orange, Raphael Tshimanga, Jean Marie Tshitenge, Gil Mahé, Cyriaque R. Nguimalet, Mark A. Trigg, Santiago Yepez, Georges Gulemvuga. Recent Budget of Hydroclimatology and Hydrosedimentology of the Congo River in Central Africa. Water. 2020; 12 (9):2613.

Chicago/Turabian Style

Alain Laraque; Guy D. Moukandi N’Kaya; Didier Orange; Raphael Tshimanga; Jean Marie Tshitenge; Gil Mahé; Cyriaque R. Nguimalet; Mark A. Trigg; Santiago Yepez; Georges Gulemvuga. 2020. "Recent Budget of Hydroclimatology and Hydrosedimentology of the Congo River in Central Africa." Water 12, no. 9: 2613.

Discussion
Published: 19 August 2020 in Sustainability
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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 Sequestration (CoCS) and conservation of carbon sinks are recognized increasingly as having potentially important roles in mitigating climate change and adapting to it. Making that potential a reality will require indicators of success for various stakeholders from multidisciplinary backgrounds, plus promotion of long-term implementation of strategic action towards civil society (e.g., law and policy makers, economists, and farmers). To help meet those challenges, this discussion paper summarizes the state of the art and uncertainties regarding CoCS, taking an interdisciplinary, holistic approach toward understanding these complex issues. The first part of the paper discusses the carbon cycle’s bio-geophysical processes, while the second introduces the plurality of geographical scales to be addressed when dealing with landscape management for CoCS. The third part addresses systemic viability, vulnerability, and resilience in CoCS practices, before concluding with the need to develop inter-disciplinarity in sustainable science, participative research, and the societal implications of sustainable CoCS actions.

ACS Style

Tiphaine Chevallier; Maud Loireau; Romain Courault; Lydie Chapuis-Lardy; Thierry Desjardins; Cécile Gomez; Alexandre Grondin; Frédéric Guérin; Didier Orange; Raphaël Pélissier; Georges Serpantié; Marie-Hélène Durand; Pierre Derioz; Gildas Laruelle Goulven; Marie-Hélène Schwoob; Nicolas Viovy; Olivier Barrière; Eric Blanchart; Vincent Blanfort; Michel Brossard; Julien Demenois; Mireille Fargette; Thierry Heulin; Gil Mahe; Raphaël Manlay; Pascal Podwojewski; Cornélia Rumpel; Benjamin Sultan; Jean-Luc Chotte. Paris Climate Agreement: Promoting Interdisciplinary Science and Stakeholders’ Approaches for Multi-Scale Implementation of Continental Carbon Sequestration. Sustainability 2020, 12, 6715 .

AMA Style

Tiphaine Chevallier, Maud Loireau, Romain Courault, Lydie Chapuis-Lardy, Thierry Desjardins, Cécile Gomez, Alexandre Grondin, Frédéric Guérin, Didier Orange, Raphaël Pélissier, Georges Serpantié, Marie-Hélène Durand, Pierre Derioz, Gildas Laruelle Goulven, Marie-Hélène Schwoob, Nicolas Viovy, Olivier Barrière, Eric Blanchart, Vincent Blanfort, Michel Brossard, Julien Demenois, Mireille Fargette, Thierry Heulin, Gil Mahe, Raphaël Manlay, Pascal Podwojewski, Cornélia Rumpel, Benjamin Sultan, Jean-Luc Chotte. Paris Climate Agreement: Promoting Interdisciplinary Science and Stakeholders’ Approaches for Multi-Scale Implementation of Continental Carbon Sequestration. Sustainability. 2020; 12 (17):6715.

Chicago/Turabian Style

Tiphaine Chevallier; Maud Loireau; Romain Courault; Lydie Chapuis-Lardy; Thierry Desjardins; Cécile Gomez; Alexandre Grondin; Frédéric Guérin; Didier Orange; Raphaël Pélissier; Georges Serpantié; Marie-Hélène Durand; Pierre Derioz; Gildas Laruelle Goulven; Marie-Hélène Schwoob; Nicolas Viovy; Olivier Barrière; Eric Blanchart; Vincent Blanfort; Michel Brossard; Julien Demenois; Mireille Fargette; Thierry Heulin; Gil Mahe; Raphaël Manlay; Pascal Podwojewski; Cornélia Rumpel; Benjamin Sultan; Jean-Luc Chotte. 2020. "Paris Climate Agreement: Promoting Interdisciplinary Science and Stakeholders’ Approaches for Multi-Scale Implementation of Continental Carbon Sequestration." Sustainability 12, no. 17: 6715.

Journal article
Published: 07 July 2020 in International Journal of Sediment Research
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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 (rainfall, water discharge, and sediment discharge) concern the Sidi Bel Attar gaging station on the Cheliff River, only 18 km from discharge to the Mediterranean Sea. A power-type statistical regression model was used to fill the 74.2% gap in Suspended Solids (SS) measurements in the establishment of a SS database for the period 1951-2012. The study results show that the transport of suspended sediment discharged to the sea is about 487 t/km2/yr. Statistical tests of breaks highlight that rainfall decreased by 26% and that water and sediment input to the sea declined from 74% to 63% for the period of 1981–2012. The correlation analysis shows a decrease in the contribution of rainfall on sediment and water input at the outlet equal to 77.9% and 77.8%, respectively, during the period of 1980-2012, compared to the period of 1968–1980. However, the double mass method reflects the contribution of factors other than rainfall to the decrease of sediment input to the sea. These other factors mainly include large dams, which intercepted about 71% of the total volume of sediment discharged to the sea during the period of 1968–2010. In addition the contribution of large dams to the reduction of sedimentary input to the sea is more important than that of the decrease in rainfall. The management of large dams also contributes to the increase in the sediment deficit to the sea through the prioritization of interception of sediment at the expense of releases, for socio-economic purposes, 68.4% of the Cheliff River discharge is diverted for human use. This has led to an increase in the mean water bed level at bankfull downstream, where the Cheliff River gave up 51% of its width to the floodplain between 1996 and 2009. In the light of the scarcity of sediment transport data in North Africa and in many other areas, the current study provides a reference framework for other studies: providing useful information for the study of the transfer of sediment from land to sea, and the links with the socio-economic needs.

ACS Style

Ali Hadour; Gil Mahé; Mohamed Meddi. Climatic and anthropogenic impacts on the decrease of sediment discharge to the Mediterranean coast from the largest river of Maghreb. International Journal of Sediment Research 2020, 36, 268 -278.

AMA Style

Ali Hadour, Gil Mahé, Mohamed Meddi. Climatic and anthropogenic impacts on the decrease of sediment discharge to the Mediterranean coast from the largest river of Maghreb. International Journal of Sediment Research. 2020; 36 (2):268-278.

Chicago/Turabian Style

Ali Hadour; Gil Mahé; Mohamed Meddi. 2020. "Climatic and anthropogenic impacts on the decrease of sediment discharge to the Mediterranean coast from the largest river of Maghreb." International Journal of Sediment Research 36, no. 2: 268-278.

Journal article
Published: 01 July 2020 in Water
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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 transport measurements on four main gauging stations at the entrance of the Sidi Mohamed Ben Abdellah dam. The application of the MUSLE on the basin demonstrated relatively small differences between the measured values and those expected for the calibrated version, these differences are, for the non-calibrated version, +5% and +102% for the years 2016/2017 and 2017/2018 respectively, and between −33% and +34% for the calibrated version. Besides, the measured and modeled volumes that do not exceed 1.78 × 106 m3/year remain well below the dam’s siltation rate of 9.49 × 106 m3/year, which means that only 18% of the dam’s sediment comes from upstream. This seems very low because it is calculated from only two years. The main hypothesis that we can formulate is that the sediments of the dam most probably comes from the erosion of its banks.

ACS Style

Mohamed Abdellah Ezzaouini; Gil Mahé; Ilias Kacimi; Abdelaziz Zerouali. Comparison of the MUSLE Model and Two Years of Solid Transport Measurement, in the Bouregreg Basin, and Impact on the Sedimentation in the Sidi Mohamed Ben Abdellah Reservoir, Morocco. Water 2020, 12, 1882 .

AMA Style

Mohamed Abdellah Ezzaouini, Gil Mahé, Ilias Kacimi, Abdelaziz Zerouali. Comparison of the MUSLE Model and Two Years of Solid Transport Measurement, in the Bouregreg Basin, and Impact on the Sedimentation in the Sidi Mohamed Ben Abdellah Reservoir, Morocco. Water. 2020; 12 (7):1882.

Chicago/Turabian Style

Mohamed Abdellah Ezzaouini; Gil Mahé; Ilias Kacimi; Abdelaziz Zerouali. 2020. "Comparison of the MUSLE Model and Two Years of Solid Transport Measurement, in the Bouregreg Basin, and Impact on the Sedimentation in the Sidi Mohamed Ben Abdellah Reservoir, Morocco." Water 12, no. 7: 1882.

Journal article
Published: 16 March 2020 in Water
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This study characterizes the future changes in extreme rainfall and air temperature in the Mono river basin where the main economic activity is weather dependent and local populations are highly vulnerable to natural hazards, including flood inundations. Daily precipitation and temperature from observational datasets and Regional Climate Models (RCMs) output from REMO, RegCM, HadRM3, and RCA were used to analyze climatic variations in space and time, and fit a GEV model to investigate the extreme rainfalls and their return periods. The results indicate that the realism of the simulated climate in this domain is mainly controlled by the choice of the RCMs. These RCMs projected a 1 to 1.5 °C temperature increase by 2050 while the projected trends for cumulated precipitation are null or very moderate and diverge among models. Contrasting results were obtained for the intense rainfall events, with RegCM and HadRM3 pointing to a significant increase in the intensity of extreme rainfall events. The GEV model is well suited for the prediction of heavy rainfall events although there are uncertainties beyond the 90th percentile. The annual maxima of daily precipitation will also increase by 2050 and could be of benefit to the ecosystem services and socioeconomic activities in the Mono river basin but could also be a threat.

ACS Style

Ernest Amoussou; Hervé Awoye; Henri S. Totin Vodounon; Salomon Obahoundje; Pierre Camberlin; Arona Diedhiou; Kouakou Kouadio; Gil Mahé; Constant Houndénou; Michel Boko. Climate and Extreme Rainfall Events in the Mono River Basin (West Africa): Investigating Future Changes with Regional Climate Models. Water 2020, 12, 833 .

AMA Style

Ernest Amoussou, Hervé Awoye, Henri S. Totin Vodounon, Salomon Obahoundje, Pierre Camberlin, Arona Diedhiou, Kouakou Kouadio, Gil Mahé, Constant Houndénou, Michel Boko. Climate and Extreme Rainfall Events in the Mono River Basin (West Africa): Investigating Future Changes with Regional Climate Models. Water. 2020; 12 (3):833.

Chicago/Turabian Style

Ernest Amoussou; Hervé Awoye; Henri S. Totin Vodounon; Salomon Obahoundje; Pierre Camberlin; Arona Diedhiou; Kouakou Kouadio; Gil Mahé; Constant Houndénou; Michel Boko. 2020. "Climate and Extreme Rainfall Events in the Mono River Basin (West Africa): Investigating Future Changes with Regional Climate Models." Water 12, no. 3: 833.

Editorial
Published: 12 August 2019 in Water
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Climate and anthropogenic changes impact on the erosion and sediment transport processes in rivers. Rainfall variability and, in many places, the increase of rainfall intensity have a direct impact on rainfall erosivity. Increasing changes in demography have led to the acceleration of land cover changes from natural areas to cultivated areas, and then from degraded areas to desertification. Such areas, under the effect of anthropogenic activities, are more sensitive to erosion, and are therefore prone to erosion. On the other hand, with an increase in the number of dams in watersheds, a great portion of sediment fluxes is trapped in the reservoirs, which do not reach the sea in the same amount nor at the same quality, and thus have consequences for coastal geomorphodynamics. The Special Issue “Modeling and Practice of Erosion and Sediment Transport under Change” is focused on a number of keywords: erosion and sediment transport, model and practice, and change. The keywords are briefly discussed with respect to the relevant literature. The papers in this Special Issue address observations and models based on laboratory and field data, allowing researchers to make use of such resources in practice under changing conditions.

ACS Style

Hafzullah Aksoy; Gil Mahe; Mohamed Meddi. Modeling and Practice of Erosion and Sediment Transport under Change. Water 2019, 11, 1665 .

AMA Style

Hafzullah Aksoy, Gil Mahe, Mohamed Meddi. Modeling and Practice of Erosion and Sediment Transport under Change. Water. 2019; 11 (8):1665.

Chicago/Turabian Style

Hafzullah Aksoy; Gil Mahe; Mohamed Meddi. 2019. "Modeling and Practice of Erosion and Sediment Transport under Change." Water 11, no. 8: 1665.

Journal article
Published: 19 March 2019 in Comptes Rendus Geoscience
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The aim of this study is the reconstitution of the recent morpho-sedimentary evolution of the Medjerda River delta. We examine the spatio-temporal evolution of the Medjerda shoreline between 1936 and 2016 using satellite images, complemented by sedimentological and geochemical analyses and 210Pbex and 137Cs radiometric data. The general tendency of the shoreline evolution shows an increasing progradation (300 ± 12 m) between 1936 and 2016. Yet the mesoscale Net Shoreline Movement position (NSM) and the End Point Rate (EPR) reveal an erosion pattern estimated to be −20 m ± 0.15 m/yr during the period 1988–1999. The sedimentological analyses reveal four main lithostratigraphic units. The fine sand substratum layer (Md = 0.08 mm) decreases toward clay and silt facies (Md < 0.063 mm), rich in continental plant debris. The geochemical results reveal gradual incoming of the terrigenous component instead of marine deposits. The 137Cs/210Pbex radiometric dating confirms the functioning of the new river flow by the 1950s with the highest sedimentation rate being 3.3 cm/yr. Our results show that the Sidi-Salem dam impoundment (1981) led to a dramatic reduction of sediment discharge, a decrease of the grain size with nearly no more sand reaching the coast, and the shoreline retreat.

ACS Style

Thouraya Ben Moussa; Oula Amrouni; Abderraouf Hzami; Laurent Dezileau; Gil Mahe; Saâdi Abdeljaouad. Progradation and retrogradation of the Medjerda delta during the 20th century (Tunisia, western Mediterranean). Comptes Rendus Geoscience 2019, 351, 340 -350.

AMA Style

Thouraya Ben Moussa, Oula Amrouni, Abderraouf Hzami, Laurent Dezileau, Gil Mahe, Saâdi Abdeljaouad. Progradation and retrogradation of the Medjerda delta during the 20th century (Tunisia, western Mediterranean). Comptes Rendus Geoscience. 2019; 351 (4):340-350.

Chicago/Turabian Style

Thouraya Ben Moussa; Oula Amrouni; Abderraouf Hzami; Laurent Dezileau; Gil Mahe; Saâdi Abdeljaouad. 2019. "Progradation and retrogradation of the Medjerda delta during the 20th century (Tunisia, western Mediterranean)." Comptes Rendus Geoscience 351, no. 4: 340-350.

Journal article
Published: 22 February 2019 in Water
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The African continent has a very low density of rain gauge stations, and long time-seriesfor recent years are often limited and poorly available. In the context of global change, it is veryimportant to be able to characterize the spatio-temporal variability of past rainfall, on the basis ofdatasets issued from observations, to correctly validate simulations. The quality of the rainfall datais for instance of very high importance to improve the efficiency of the hydrological modeling,through calibration/validation experiments.The HydroSciences Montpellier Laboratory (HSM) has a long experience in collecting andmanaging hydro-climatological data. Thus, HSM had initiated a program to elaborate a referencedataset, in order to build monthly rainfall grids over the African continent, over a period of 60 years(1940/1999). The large quantity of data collected (about 7,000 measurement points were used in thisproject) allowed for interpolation using only observed data, with no statistical use of a referenceperiod. Compared to other databases that are used to build the grids of the Global HistoricalClimatology Network (GHCN) or the Climatic Research Unit of University of East Anglia, UK (CRU),the number of available observational stations (a was significantly much higher, including the end ofthe century when the number of measurement stations dropped dramatically, everywhere.Inverse distance weighed (IDW) was the chosen method to build the 720 monthly grids and amean annual grid, from rain gauges. The mean annual grid was compared to the CRU grid. The gridswere significantly different in many places, especially in North Africa, Sahel, the horn of Africa, andthe South Western coast of Africa, with HSM_SIEREM data (database HydroSciencesMontpellier_Système d’Information Environnementales pour les Ressources en Eau et leurModélisation) being closer to the observed rain gauge values. The quality of the grids computed waschecked, following two approaches—cross-validation of the two interpolation methods, ordinarykriging and inverse distance weighting, which gave a comparable reliability, with regards to theobserved data, long time-series analysis, and analysis of long-term signals over the continent,compared to previous studies. The statistical tests, computed on the observed and gridded data,detected a rupture in the rainfall regime around 1979/1980, on the scale of the whole continent; thiswas congruent with the results in the literature. At the monthly time-scale, the most widely observedsignal over the period of 1940/1999, was a significant decrease of the austral rainy season betweenMarch and May, which has not earlier been well-documented. Thus, this would lead to a furtherdetailed climatological study from this HSM_SIEREM database.

ACS Style

Claudine Dieulin; Gil Mahé; Jean-Emmanuel Paturel; Soundouss Ejjiyar; Yves Tramblay; Nathalie Rouché; Bouabid El Mansouri. A New 60-year 1940/1999 Monthly-Gridded Rainfall Data Set for Africa. Water 2019, 11, 387 .

AMA Style

Claudine Dieulin, Gil Mahé, Jean-Emmanuel Paturel, Soundouss Ejjiyar, Yves Tramblay, Nathalie Rouché, Bouabid El Mansouri. A New 60-year 1940/1999 Monthly-Gridded Rainfall Data Set for Africa. Water. 2019; 11 (2):387.

Chicago/Turabian Style

Claudine Dieulin; Gil Mahé; Jean-Emmanuel Paturel; Soundouss Ejjiyar; Yves Tramblay; Nathalie Rouché; Bouabid El Mansouri. 2019. "A New 60-year 1940/1999 Monthly-Gridded Rainfall Data Set for Africa." Water 11, no. 2: 387.

Journal article
Published: 01 January 2019 in Atmósfera
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Sabrina Taïbi; Mohamed Meddi; Gil Mahé; Laboratoire Génie De L’Eau Et L’Environnement Ecole Nationale Supérieure D’Hydraulique (Ensh); IRD HydroSciences Montpellier Université. Seasonal rainfall variability in the southern Mediterranean border: Observations, regional model simulations and future climate projections. Atmósfera 2019, 32, 39 -54.

AMA Style

Sabrina Taïbi, Mohamed Meddi, Gil Mahé, Laboratoire Génie De L’Eau Et L’Environnement Ecole Nationale Supérieure D’Hydraulique (Ensh), IRD HydroSciences Montpellier Université. Seasonal rainfall variability in the southern Mediterranean border: Observations, regional model simulations and future climate projections. Atmósfera. 2019; 32 (1):39-54.

Chicago/Turabian Style

Sabrina Taïbi; Mohamed Meddi; Gil Mahé; Laboratoire Génie De L’Eau Et L’Environnement Ecole Nationale Supérieure D’Hydraulique (Ensh); IRD HydroSciences Montpellier Université. 2019. "Seasonal rainfall variability in the southern Mediterranean border: Observations, regional model simulations and future climate projections." Atmósfera 32, no. 1: 39-54.

Journal article
Published: 04 July 2018 in Water
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The objective of this study was to follow-up on the evolution of the hydro-pluviometric schemes and particular elements of Wadi Mina (6048 km2) to the Sidi M’Hamed Ben Aouda Dam to evaluate the silting origin and status of this dam situated in the northwest of Algeria. The pluviometric study targeted a series of rains during 77 years (1930–2007), the liquid discharge data cover a period of 41 years (1969–2010) and the solids and suspended sediment concentrations data cover very variable periods, starting from 22 to 40 years for the entire catchment area. The statistical tests for ruptures detection on the chronological series of rains and discharges indicate a net reduction of rains of more than 20% on the entire basin since 1970. The evolution of solids inputs was quantified: the maximum values are registered on autumn start and at the end of spring. The Wadi Mina basin brings annually 38 × 106 m3 of water with a specific degradation of 860 t·km−2·year−1. By comparing the results found, we thus observe that the basin upstream of SMBA (1B) Dam is the greatest sediment producer towards the dam because it shows a specific degradation equal to 13.36 t·ha−1·year−1.

ACS Style

Faiza Hallouz; Mohamed Meddi; Gil Mahé; Samir Toumi; Salah Eddine Ali Rahmani. Erosion, Suspended Sediment Transport and Sedimentation on the Wadi Mina at the Sidi M’Hamed Ben Aouda Dam, Algeria. Water 2018, 10, 895 .

AMA Style

Faiza Hallouz, Mohamed Meddi, Gil Mahé, Samir Toumi, Salah Eddine Ali Rahmani. Erosion, Suspended Sediment Transport and Sedimentation on the Wadi Mina at the Sidi M’Hamed Ben Aouda Dam, Algeria. Water. 2018; 10 (7):895.

Chicago/Turabian Style

Faiza Hallouz; Mohamed Meddi; Gil Mahé; Samir Toumi; Salah Eddine Ali Rahmani. 2018. "Erosion, Suspended Sediment Transport and Sedimentation on the Wadi Mina at the Sidi M’Hamed Ben Aouda Dam, Algeria." Water 10, no. 7: 895.

Journal article
Published: 08 June 2018 in Water
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In the West African Sahel, two paradoxical hydrological behaviors have occurred during the last five decades. The first paradox was observed during the 1968–1990s ‘Great Drought’ period, during which runoff significantly increased. The second paradox appeared during the subsequent period of rainfall recovery (i.e., since the 1990s), during which the runoff coefficient continued to increase despite the general re-greening of the Sahel. This paper reviews and synthesizes the literature on the drivers of these paradoxical behaviors, focusing on recent works in the West African Sahelo/Sudanian strip, and upscaling the hydrological processes through an analysis of recent data from two representative areas of this region. This paper helps better determine the respective roles played by Land Use/Land Cover Changes (LULCC), the evolution of rainfall intensity and the occurrence of extreme rainfall events in these hydrological paradoxes. Both the literature review and recent data converge in indicating that the first Sahelian hydrological paradox was mostly driven by LULCC, while the second paradox has been caused by both LULCC and climate evolution, mainly the recent increase in rainfall intensity.

ACS Style

Luc Descroix; Françoise Guichard; Manuela Grippa; Laurent A. Lambert; Gérémy Panthou; Gil Mahé; Laetitia Gal; Cécile Dardel; Guillaume Quantin; Laurent Kergoat; Yasmin Bouaïta; Pierre Hiernaux; Théo Vischel; Thierry Pellarin; Bakary Faty; Catherine Wilcox; Moussa Malam Abdou; Ibrahim Mamadou; Jean-Pierre Vandervaere; Aïda Diongue-Niang; Ousmane Ndiaye; Youssouph Sané; Honoré Dacosta; Marielle Gosset; Claire Cassé; Benjamin Sultan; Aliou Barry; Okechukwu Amogu; Bernadette Nka Nnomo; Alseny Barry; Jean-Emmanuel Paturel. Evolution of Surface Hydrology in the Sahelo-Sudanian Strip: An Updated Review. Water 2018, 10, 748 .

AMA Style

Luc Descroix, Françoise Guichard, Manuela Grippa, Laurent A. Lambert, Gérémy Panthou, Gil Mahé, Laetitia Gal, Cécile Dardel, Guillaume Quantin, Laurent Kergoat, Yasmin Bouaïta, Pierre Hiernaux, Théo Vischel, Thierry Pellarin, Bakary Faty, Catherine Wilcox, Moussa Malam Abdou, Ibrahim Mamadou, Jean-Pierre Vandervaere, Aïda Diongue-Niang, Ousmane Ndiaye, Youssouph Sané, Honoré Dacosta, Marielle Gosset, Claire Cassé, Benjamin Sultan, Aliou Barry, Okechukwu Amogu, Bernadette Nka Nnomo, Alseny Barry, Jean-Emmanuel Paturel. Evolution of Surface Hydrology in the Sahelo-Sudanian Strip: An Updated Review. Water. 2018; 10 (6):748.

Chicago/Turabian Style

Luc Descroix; Françoise Guichard; Manuela Grippa; Laurent A. Lambert; Gérémy Panthou; Gil Mahé; Laetitia Gal; Cécile Dardel; Guillaume Quantin; Laurent Kergoat; Yasmin Bouaïta; Pierre Hiernaux; Théo Vischel; Thierry Pellarin; Bakary Faty; Catherine Wilcox; Moussa Malam Abdou; Ibrahim Mamadou; Jean-Pierre Vandervaere; Aïda Diongue-Niang; Ousmane Ndiaye; Youssouph Sané; Honoré Dacosta; Marielle Gosset; Claire Cassé; Benjamin Sultan; Aliou Barry; Okechukwu Amogu; Bernadette Nka Nnomo; Alseny Barry; Jean-Emmanuel Paturel. 2018. "Evolution of Surface Hydrology in the Sahelo-Sudanian Strip: An Updated Review." Water 10, no. 6: 748.

Conference paper
Published: 16 April 2018 in Proceedings of the International Association of Hydrological Sciences
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ACS Style

Gil Mahé; Kate Heal; Akhilendra B. Gupta; Hafzullah Aksoy. Preface: Water quality and sediment transport issues in surface water. Proceedings of the International Association of Hydrological Sciences 2018, 377, 1 -1.

AMA Style

Gil Mahé, Kate Heal, Akhilendra B. Gupta, Hafzullah Aksoy. Preface: Water quality and sediment transport issues in surface water. Proceedings of the International Association of Hydrological Sciences. 2018; 377 ():1-1.

Chicago/Turabian Style

Gil Mahé; Kate Heal; Akhilendra B. Gupta; Hafzullah Aksoy. 2018. "Preface: Water quality and sediment transport issues in surface water." Proceedings of the International Association of Hydrological Sciences 377, no. : 1-1.

Journal article
Published: 01 April 2018 in Water Science
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The objective of this study is to model discharge and solid erosion quantification through a small agricultural watershed by applying the SWAT model (Soil and Water Assessment Tools) on the Wadi Harraza’s basin of which is part of Wadi Cheliff’s basin, with an average altitude of 500 m, drains an area of 568 sq km. Soil and Water Assessment Tool (SWAT, version 2009) model integrated with Geographic Information System (ArcGIS, version 10.0) were used to simulate the discharge and sediment concentration of Wadi Harraza’s basin for the period from 2004 to 2009. Model calibration and validation were performed for monthly time periods using Sequential Uncertainty Fitting 2 (SUFI-2, version 2) within SWAT-CUP. Our calibration and validation outputs for monthly simulation showed a good model performance for discharges. Thus the evolution of the average total annual sediment in the Wadi Harraza’s basin which will be deposited in the Wadi Cheliff, is estimated at 54.24 t ha−1.

ACS Style

Faiza Hallouz; Mohamed Meddi; Gil Mahé; Salaheddine Alirahmani; Abdelkader Keddar. Modeling of discharge and sediment transport through the SWAT model in the basin of Harraza (Northwest of Algeria). Water Science 2018, 32, 79 -88.

AMA Style

Faiza Hallouz, Mohamed Meddi, Gil Mahé, Salaheddine Alirahmani, Abdelkader Keddar. Modeling of discharge and sediment transport through the SWAT model in the basin of Harraza (Northwest of Algeria). Water Science. 2018; 32 (1):79-88.

Chicago/Turabian Style

Faiza Hallouz; Mohamed Meddi; Gil Mahé; Salaheddine Alirahmani; Abdelkader Keddar. 2018. "Modeling of discharge and sediment transport through the SWAT model in the basin of Harraza (Northwest of Algeria)." Water Science 32, no. 1: 79-88.

Preprint
Published: 12 March 2018
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The study aims to analyze the performance criteria of the GR4J model to reproduce high water flows in the Ouémé watershed at Bonou's outlet which has been vulnerable to climate change in recent decades. The methodology focused on the use of daily climatological and hydrometric data extracted from files of National Directorate of Meteorology, and General Directorate of Water; they were supplemented by those of SIEREM/HSM dataset over the period 1961-2015. The rainfall was regionalized using Thiessen method. The performance of the GR4J model was assessed with NSE, RMSE and KGE criteria. The results indicate that the study area is marked by rainfall variabilities and detection of two breakpoints (1968 and 1987) which divide the series into three sub-periods; these discontinuities have repercussions on the streamflow. It's found that GR4J model overestimates the streamflow during the low water period and underestimates them in high water. However, the efficiency and performance criteria NSE, RMSE and KGE calculated on high water flow rates are better in calibration than in validation. The KGE values are range between 83-85% in calibration and 56-68% during validation, which gives to GR4J model the efficiency and performance to reproduce high flow rates in the study area

ACS Style

Domiho Japhet Kodja; Gil Mahe; Ernest Amoussou; Michel Boko; Jean-Emmanuel Paturel. Assessment of the Performance of Rainfall-Runoff Model GR4J to Simulate Streamflow in Ouémé Watershed at Bonou’s outlet (West Africa). 2018, 1 .

AMA Style

Domiho Japhet Kodja, Gil Mahe, Ernest Amoussou, Michel Boko, Jean-Emmanuel Paturel. Assessment of the Performance of Rainfall-Runoff Model GR4J to Simulate Streamflow in Ouémé Watershed at Bonou’s outlet (West Africa). . 2018; ():1.

Chicago/Turabian Style

Domiho Japhet Kodja; Gil Mahe; Ernest Amoussou; Michel Boko; Jean-Emmanuel Paturel. 2018. "Assessment of the Performance of Rainfall-Runoff Model GR4J to Simulate Streamflow in Ouémé Watershed at Bonou’s outlet (West Africa)." , no. : 1.