En Algérie, les terres sont soumises à des inondations répétées dont les conséquences se traduise... more En Algérie, les terres sont soumises à des inondations répétées dont les conséquences se traduisent par la dégradation des voies de communication, l’inondation des terres agricoles occupant les dépressions et les terrasses alluviales, et parfois même par l’inondation de certaines agglomérations entrainant quelquefois des pertes humaines.Les inondations des agglomérations résultent de pluies torrentielles dont les effets sont souvent amplifiés par les facteurs naturels du relief et d’autres facteurs liés à une urbanisation anarchique (construction en zones inondables) et non maîtrisées (manque d’entretien des réseaux d’assainissement), bassin versant dénudé, passage de feux de forêts sur le versant….La petite agglomération du village Tafna – Tlemcen, situé sur la rive de l’oued de Tafna présente un grand risque d’inondation par l’oued mais surtout par les versants marneux dénudés qui surplombent le village. Dans le cadre de la lutte contre les inondations, des techniques antiérosives ont été réalisées pour atténuer le phénomène érosif sur les versants concernés et pour stopper et diriger en aval les eaux de ruissellement afin de protéger l’agglomération se trouvant en aval. Les versants sont traités par des aménagements de correction torrentielle (seuils en gabions et en pierres sèches) en vue d’un traitement efficace et durable contre les inondations. A l’aval des canaux (qui ressemblent beaucoup aux banquettes) parallèles aux courbes de niveau les talus ont été ouverts pour évacuer les eaux de ruissellement vers des exutoires naturels et où le bourrelet est renforcé par un muret cimenté.Cette étude a pour objectif l’évaluation de l’impact de ces aménagements sur l’atténuation des inondations. La méthode repose sur des investigations de terrain et sur des enquêtes auprès de la population locale.Les résultats montrent que les aménagements ont bien fonctionné pour étaler les pointes de crues et dans la rétention des sédiments, mais une fois remplis, les eaux de ruissellement très chargées ont continué à menacer la population. Les digues d’aval se sont rapidement envasées et le débordement des eaux a causé beaucoup de ruptures ce qui a encore amplifié le phénomène d’inondation. Les dispositions prise ne semblent pas bien adaptées à ce type de milieu argileux très instable. Dans ce type de milieu, il est recommandé de prendre des mesures préventives par : une conception d’aménagement globale (formulation et mise place de vraies réponses bien structurées selon une démarche globale), le bon choix des techniques adaptables (mécaniques mais surtout biologiques), l’entretien et le suivi continu des aménagements et le respect des instruments d’urbanisme. Par exemple, il faut interdire les constructions à l’aval des versants instables et en bordure des oueds qui présentent de grands risques
As far as industry, agriculture, urbanization, lithology and climate are concerned, surface-water... more As far as industry, agriculture, urbanization, lithology and climate are concerned, surface-water vulnerability to pollution has not ceased to amplify especially in semi-arid to arid areas. In the countries of the southern shore of the Mediterranean and most particularly in Algeria, surface-water quality is highly impacted by anthropogenic activities and climate change. It thus requires a complete diagnosis of the evolution of these impacts through a survey. The present study aims at characterizing and assessing the temporal evolution of surface-water quality in Sikkak wadi watershed (north-western Algeria), particularly at the Sikkak dam. The methodology that was applied to assess and interpret monthly surface-water quality results gathered throughout an 11-year period of time survey (2005À2015) included the following: a quality-grading method, a trend-following approach, a seasonal analysis as well as a principal components analysis (PCA). The results analyzed according to the classification of the Algerian National Agency for Water Resources (ANRH) revealed that the Sikkak dam water is characterized by a natural mineralization that is good (61.37%) to medium (38.63%) taking into account electrical conductivity (EC), chloride, sodium, calcium, magnesium and sulfate contents. However, it is found to be highly contaminated by organic pollution ranging from bad grade (46.37%) to fairly medium quality (34.98%). COD, BOD, nitrate, nitrite, ammonium and orthophosphate were used as the evaluation parameters. In general and taking into account all the parameters of pollution, the 'medium' and 'good' classes dominate the quality of the surface water of the Sikkak dam with a percentage of 40.37% and 37.28% successively, followed by the 'poor' (20.72%) and 'very poor' (1.63%) classes. The trend-following method shows that the surveyed waters moderately tend towards more alkaline and exhibit increasing COD and chloride. Further, the waters show a decreasing EC, BOD 5 , organic matter, nitrogen and phosphate as well as most of the salinizing and carbonating compounds. This is mainly due to the contribution of wastewater treatment plant in improving the water quality. The PCA confirmed that the different forms of pollution (domestic, industrial, agricultural) and salinization (for 56.77%) are the main factors for the degradation of the quality of the dam water.
During the last three decades, citizens of an Algerian city are concerned with the problem of dri... more During the last three decades, citizens of an Algerian city are concerned with the problem of drinking water supply. Time discontinuation service became the rule. The central idea of the analysis based on interviews is to assess the role of water in the organization of the relationship between habitat and users. The fundamental question is how users, in particular women, incorporate water in their daily lives due to rationing. Having to deal with the discontinuous and frequent weak water supply, the inhabitants of the city of Tlemcen who are connected to the water supply system, as well as those connected to the water system of all Algerian towns, have developed an internal water storage system to sort out this problem. The imposed rationing has proved to be expensive for consumers. The water shortage pushed the consumers to invest in relatively expensive storage and pumping facilities to satisfy their domestic needs. As the frequency of the water supply is on a two times per week basis, the survey reveals a discrepancy in terms of volumes consumed and stored by each household. The use of water depends on the individual storage facility and the frequency of the supply. The life of the households, particularly that of the housewives, depends on the availability of water and thus on the schedules of the Company of Production of Water ''Algerian Des Eaux'' (ADE). This is particularly the case when they are supplied during the night.
La régulation des services d'eau est un sujet de plus en plus d'actualité en Algérie. La régulati... more La régulation des services d'eau est un sujet de plus en plus d'actualité en Algérie. La régulation des services d'eau est de la compétence des gestionnaires de secteur de l'eau, ce sont eux qui décident des investissements, qui organisent l'exploitation et qui négocient le prix. Si l'usager est le destinataire du service, il n'intervient que très indirectement dans les choix de gestion. Partant du constat de la limite du contrôle sur les moyens et de l'insuffisance des instruments de suivi et de contrôle, dégagés de l'analyse de l'état des lieux, ce travail vient renforcer les actions déjà entamées par le gestionnaire du secteur et propose un panel d'indicateurs de performance, les plus simples et facilement mesurables, comme outil adéquat pour assurer la fonction de régulation. Le groupe d'indicateur ainsi élaboré et testé sur le Groupement
permet l'utilisation sans restriction, la distribution et la reproduction sur tout support, à con... more permet l'utilisation sans restriction, la distribution et la reproduction sur tout support, à condition que le travail original soit correctement cité.
Environmental Monitoring and Assessment, Jan 9, 2021
The importance of the soil degradation in the Mediterranean area, more particularly in Algeria, h... more The importance of the soil degradation in the Mediterranean area, more particularly in Algeria, has revealed the need for a diagnosis of the erosion processes’ dynamism. In this context, the present work discusses the results obtained by different approaches (conventional methods, Revised Universal Soil Loss Equation (RUSLE), and fallout radionuclides (use of FRNs)). The use of nuclear techniques (FRNs) such as Cesium-137, Lead-210, and Beryllium-7 as tracers can provide an invaluable amount of information on rates of soil loss that is associated with sheet and rill erosion as well as on the redistribution and transfer of that sediment within the landscape. This work mainly presents the results obtained by the application of nuclear isotopes. In the Fergoug watershed study, the use of conventional and nuclear methods has led to converging results. The latter can be summarized as follows: sheet erosion from 1.5 to 10 t·ha−1·year−1 for bare soil and 0.1 to 4 t·ha−1·year−1 for cultivated soil. The use of the RUSLE method has shown that erosion is medium to very high (1 to 33 t·ha−1·year−1). Estimates of erosion by Cesium-137 (137Cs) provided a good understanding of the distribution of the isotope at the slope level and therefore of erosion. The erosion rate is from 26 to 42 t·ha-1·year-1, depending on the models used. On the other hand, sedimentation reached 35 and 55 t·ha-1·year-1 downstream of the slopes. The variation of 137Cs between transects and along the same transect is linked to erosion. The 137Cs method has provided a great deal of information and thus constitutes, by its accuracy and speed, an effective and valuable tool for assessing erosion for medium term (50 years) and monitoring the impacts of land use. It can enable one to overcome the various constraints and limits encountered in the various conventional approaches. It thus appears to be an essential alternative or an effective tool to supplement the conventional methods.
RESUME : L'alternance sécheresse-réhydratation des sols entraîne un comportement hydrodynamique p... more RESUME : L'alternance sécheresse-réhydratation des sols entraîne un comportement hydrodynamique particulier des sols argileux et par conséquent des risques de mouvement en masse et d'érosion. Cette étude rentre dans ce cadre et a permis de contribuer à la compréhension de cette dynamique (évolution de l'infiltration, du ruissellement et du phénomène de retrait) par l'utilisation de la simulation de pluie, outil permettant de reproduire sur le terrain les conditions correspondant à une pluie naturelle. Les résultats obtenus ont bien montré l'influence de l'humidité préalable du sol, de l'intensité de la pluie et l'état de surface sur le comportement hydrodynamique. L'écoulement de l'eau dans le sol argileux est de deux types : un écoulement lent (écoulement au niveau de la microporosité du sol) qui se réalise lorsque le sol est humide et fermé (non fissuré) et un écoulement rapide par l'intermédiaire de la macroporosité (écoulement privilégié et hypodermique).
Ce travail de recherche a été consacré à l'étude d'un problème d'actualité, à savoir la pollution... more Ce travail de recherche a été consacré à l'étude d'un problème d'actualité, à savoir la pollution des nappes phréatiques côtières par l'invasion des eaux marines qui s'accentue de plus en plus avec les changements climatiques et l'accroissement de la démographie et des besoins. Sur la nappe côtière d'Alger Est, caractérisée par une exploitation intensive et anarchique, nous avons essayé par une approche pluridisciplinaire, combinant plusieurs méthodes (piézométrique, chimique et géophysique) de mettre en évidence une intrusion marine et de déceler les zones sensibles à la pollution marine dans cette zone côtière et d'analyser les répercussions sur la dégradation des sols par l'utilisation des eaux d'irrigation polluées par la mer. Les résultats obtenus par cette approche ont permis de mettre en évidence une invasion marine et de localiser différentes zones sensibles dans cet aquifère côtier. Les causes principales de ce phénomène sont dues principalement aux pompages intensifs associés au déficit pluviométrique et à la nature lithologique des aquifères. Ces facteurs engendrent une perturbation au niveau de l'interface eau douce-eau salée et accentuent l'avancement des eaux marines vers le continent.
A navegação consulta e descarregamento dos títulos inseridos nas Bibliotecas Digitais UC Digitali... more A navegação consulta e descarregamento dos títulos inseridos nas Bibliotecas Digitais UC Digitalis, UC Pombalina e UC Impactum, pressupõem a aceitação plena e sem reservas dos Termos e Condições de Uso destas Bibliotecas Digitais, disponíveis em https://digitalis.uc.pt/pt-pt/termos. Conforme exposto nos referidos Termos e Condições de Uso, o descarregamento de títulos de acesso restrito requer uma licença válida de autorização devendo o utilizador aceder ao(s) documento(s) a partir de um endereço de IP da instituição detentora da supramencionada licença. Ao utilizador é apenas permitido o descarregamento para uso pessoal, pelo que o emprego do(s) título(s) descarregado(s) para outro fim, designadamente comercial, carece de autorização do respetivo autor ou editor da obra. Na medida em que todas as obras da UC Digitalis se encontram protegidas pelo Código do Direito de Autor e Direitos Conexos e demais legislação aplicável, toda a cópia, parcial ou total, deste documento, nos casos em que é legalmente admitida, deverá conter ou fazer-se acompanhar por este aviso. Impact de la dynamique agricole sur la durabilité des périmètres agricoles traditionnels: cas des oasis des monts du Ksour-Algérie
Stepped spillway is hydraulic structure designed to dissipate considerable kinetic energy because... more Stepped spillway is hydraulic structure designed to dissipate considerable kinetic energy because it's characterised by the large value of the surface roughness. On stepped chutes with skimming flow regime, the flow is highly aerated which can reduce the risk of cavitation. The air entrainment starts where the boundary layer attains the free surface of flow; this point is called “ point of inception ”. In the present numerical study, the Reynolds-Averaged Navier–Stokes equations are coupled with k −e turbulence standard model to simulate the water flow over stepped spillway by using the software Ansys Fluent. Volume of fluid (VOF) model is used as a tool to track the free surface flow. This research aims to find new formulas for describe the variation of water depth and the positions of the inception point. In addition, to study the characteristics of flow over stepped spillways. The found numerical results agree well with experimental results.
The main topics of the extended abstract should fit within the areas of water, energy, climate ch... more The main topics of the extended abstract should fit within the areas of water, energy, climate change, the nexus within water, energy and climate change. The abstract should also be in line with ongoing projects and priorities of the research agenda at PAUWES as a contribution to the Agenda 2063 of the African union.
To assess seasonal patterns of suspended sediment load and its erosiontransport interactions, 17 ... more To assess seasonal patterns of suspended sediment load and its erosiontransport interactions, 17 years of river monitoring data from the Isser River Basin (northwest Algeria) was studied, considering continuous and event-scale approaches. The results show significant differences in sediment yield and transport processes between dry and wet periods. A rate of 8 t ha-1 year-1 was estimated from continuous analysis, with values of 4.3 and 13 t ha-1 year-1 for wet and dry periods, respectively. Estimates of soil delivery ratio pointed to higher values during dry periods and the dominance of hillslope erosion processes. At the event scale, the hysteresis loops confirmed these seasonal patterns in transport dynamics. The calibration of the MUSLE model highlighted the severity of rainfall during the dry period. These results emphasize the importance of seasonality in erosion and transport processes with special relevance in terms of climate change predictions.
This work describes the climate change impact study on rainfall patterns in Macta watershed, loca... more This work describes the climate change impact study on rainfall patterns in Macta watershed, located in the northwest of Algeria. The monthly rainfall data collection, verification and validation have built a database with 42 stations, each with 42 years of observations from 1970 to 2011. The study of annual total rainfall has identified a downward trend and quantifies the deficits that are within the observation time series. The division of the annual rainfall series into four periods allowed to highlighting the increase in inter-year temporal variability with the coefficient of variation increases from 17 to 27%. The study shows an annual rainfall deficit increment from 13 to 25%. The standard deviation values decrease significantly for the last two periods showing a spatial variability. Multivariate statistical study by the hierarchical clustering method resulted in the formation of station groups indicating the unification of monthly rainfall patterns.
En Algérie, les terres sont soumises à des inondations répétées dont les conséquences se traduise... more En Algérie, les terres sont soumises à des inondations répétées dont les conséquences se traduisent par la dégradation des voies de communication, l’inondation des terres agricoles occupant les dépressions et les terrasses alluviales, et parfois même par l’inondation de certaines agglomérations entrainant quelquefois des pertes humaines.Les inondations des agglomérations résultent de pluies torrentielles dont les effets sont souvent amplifiés par les facteurs naturels du relief et d’autres facteurs liés à une urbanisation anarchique (construction en zones inondables) et non maîtrisées (manque d’entretien des réseaux d’assainissement), bassin versant dénudé, passage de feux de forêts sur le versant….La petite agglomération du village Tafna – Tlemcen, situé sur la rive de l’oued de Tafna présente un grand risque d’inondation par l’oued mais surtout par les versants marneux dénudés qui surplombent le village. Dans le cadre de la lutte contre les inondations, des techniques antiérosives ont été réalisées pour atténuer le phénomène érosif sur les versants concernés et pour stopper et diriger en aval les eaux de ruissellement afin de protéger l’agglomération se trouvant en aval. Les versants sont traités par des aménagements de correction torrentielle (seuils en gabions et en pierres sèches) en vue d’un traitement efficace et durable contre les inondations. A l’aval des canaux (qui ressemblent beaucoup aux banquettes) parallèles aux courbes de niveau les talus ont été ouverts pour évacuer les eaux de ruissellement vers des exutoires naturels et où le bourrelet est renforcé par un muret cimenté.Cette étude a pour objectif l’évaluation de l’impact de ces aménagements sur l’atténuation des inondations. La méthode repose sur des investigations de terrain et sur des enquêtes auprès de la population locale.Les résultats montrent que les aménagements ont bien fonctionné pour étaler les pointes de crues et dans la rétention des sédiments, mais une fois remplis, les eaux de ruissellement très chargées ont continué à menacer la population. Les digues d’aval se sont rapidement envasées et le débordement des eaux a causé beaucoup de ruptures ce qui a encore amplifié le phénomène d’inondation. Les dispositions prise ne semblent pas bien adaptées à ce type de milieu argileux très instable. Dans ce type de milieu, il est recommandé de prendre des mesures préventives par : une conception d’aménagement globale (formulation et mise place de vraies réponses bien structurées selon une démarche globale), le bon choix des techniques adaptables (mécaniques mais surtout biologiques), l’entretien et le suivi continu des aménagements et le respect des instruments d’urbanisme. Par exemple, il faut interdire les constructions à l’aval des versants instables et en bordure des oueds qui présentent de grands risques
As far as industry, agriculture, urbanization, lithology and climate are concerned, surface-water... more As far as industry, agriculture, urbanization, lithology and climate are concerned, surface-water vulnerability to pollution has not ceased to amplify especially in semi-arid to arid areas. In the countries of the southern shore of the Mediterranean and most particularly in Algeria, surface-water quality is highly impacted by anthropogenic activities and climate change. It thus requires a complete diagnosis of the evolution of these impacts through a survey. The present study aims at characterizing and assessing the temporal evolution of surface-water quality in Sikkak wadi watershed (north-western Algeria), particularly at the Sikkak dam. The methodology that was applied to assess and interpret monthly surface-water quality results gathered throughout an 11-year period of time survey (2005À2015) included the following: a quality-grading method, a trend-following approach, a seasonal analysis as well as a principal components analysis (PCA). The results analyzed according to the classification of the Algerian National Agency for Water Resources (ANRH) revealed that the Sikkak dam water is characterized by a natural mineralization that is good (61.37%) to medium (38.63%) taking into account electrical conductivity (EC), chloride, sodium, calcium, magnesium and sulfate contents. However, it is found to be highly contaminated by organic pollution ranging from bad grade (46.37%) to fairly medium quality (34.98%). COD, BOD, nitrate, nitrite, ammonium and orthophosphate were used as the evaluation parameters. In general and taking into account all the parameters of pollution, the 'medium' and 'good' classes dominate the quality of the surface water of the Sikkak dam with a percentage of 40.37% and 37.28% successively, followed by the 'poor' (20.72%) and 'very poor' (1.63%) classes. The trend-following method shows that the surveyed waters moderately tend towards more alkaline and exhibit increasing COD and chloride. Further, the waters show a decreasing EC, BOD 5 , organic matter, nitrogen and phosphate as well as most of the salinizing and carbonating compounds. This is mainly due to the contribution of wastewater treatment plant in improving the water quality. The PCA confirmed that the different forms of pollution (domestic, industrial, agricultural) and salinization (for 56.77%) are the main factors for the degradation of the quality of the dam water.
During the last three decades, citizens of an Algerian city are concerned with the problem of dri... more During the last three decades, citizens of an Algerian city are concerned with the problem of drinking water supply. Time discontinuation service became the rule. The central idea of the analysis based on interviews is to assess the role of water in the organization of the relationship between habitat and users. The fundamental question is how users, in particular women, incorporate water in their daily lives due to rationing. Having to deal with the discontinuous and frequent weak water supply, the inhabitants of the city of Tlemcen who are connected to the water supply system, as well as those connected to the water system of all Algerian towns, have developed an internal water storage system to sort out this problem. The imposed rationing has proved to be expensive for consumers. The water shortage pushed the consumers to invest in relatively expensive storage and pumping facilities to satisfy their domestic needs. As the frequency of the water supply is on a two times per week basis, the survey reveals a discrepancy in terms of volumes consumed and stored by each household. The use of water depends on the individual storage facility and the frequency of the supply. The life of the households, particularly that of the housewives, depends on the availability of water and thus on the schedules of the Company of Production of Water ''Algerian Des Eaux'' (ADE). This is particularly the case when they are supplied during the night.
La régulation des services d'eau est un sujet de plus en plus d'actualité en Algérie. La régulati... more La régulation des services d'eau est un sujet de plus en plus d'actualité en Algérie. La régulation des services d'eau est de la compétence des gestionnaires de secteur de l'eau, ce sont eux qui décident des investissements, qui organisent l'exploitation et qui négocient le prix. Si l'usager est le destinataire du service, il n'intervient que très indirectement dans les choix de gestion. Partant du constat de la limite du contrôle sur les moyens et de l'insuffisance des instruments de suivi et de contrôle, dégagés de l'analyse de l'état des lieux, ce travail vient renforcer les actions déjà entamées par le gestionnaire du secteur et propose un panel d'indicateurs de performance, les plus simples et facilement mesurables, comme outil adéquat pour assurer la fonction de régulation. Le groupe d'indicateur ainsi élaboré et testé sur le Groupement
permet l'utilisation sans restriction, la distribution et la reproduction sur tout support, à con... more permet l'utilisation sans restriction, la distribution et la reproduction sur tout support, à condition que le travail original soit correctement cité.
Environmental Monitoring and Assessment, Jan 9, 2021
The importance of the soil degradation in the Mediterranean area, more particularly in Algeria, h... more The importance of the soil degradation in the Mediterranean area, more particularly in Algeria, has revealed the need for a diagnosis of the erosion processes’ dynamism. In this context, the present work discusses the results obtained by different approaches (conventional methods, Revised Universal Soil Loss Equation (RUSLE), and fallout radionuclides (use of FRNs)). The use of nuclear techniques (FRNs) such as Cesium-137, Lead-210, and Beryllium-7 as tracers can provide an invaluable amount of information on rates of soil loss that is associated with sheet and rill erosion as well as on the redistribution and transfer of that sediment within the landscape. This work mainly presents the results obtained by the application of nuclear isotopes. In the Fergoug watershed study, the use of conventional and nuclear methods has led to converging results. The latter can be summarized as follows: sheet erosion from 1.5 to 10 t·ha−1·year−1 for bare soil and 0.1 to 4 t·ha−1·year−1 for cultivated soil. The use of the RUSLE method has shown that erosion is medium to very high (1 to 33 t·ha−1·year−1). Estimates of erosion by Cesium-137 (137Cs) provided a good understanding of the distribution of the isotope at the slope level and therefore of erosion. The erosion rate is from 26 to 42 t·ha-1·year-1, depending on the models used. On the other hand, sedimentation reached 35 and 55 t·ha-1·year-1 downstream of the slopes. The variation of 137Cs between transects and along the same transect is linked to erosion. The 137Cs method has provided a great deal of information and thus constitutes, by its accuracy and speed, an effective and valuable tool for assessing erosion for medium term (50 years) and monitoring the impacts of land use. It can enable one to overcome the various constraints and limits encountered in the various conventional approaches. It thus appears to be an essential alternative or an effective tool to supplement the conventional methods.
RESUME : L'alternance sécheresse-réhydratation des sols entraîne un comportement hydrodynamique p... more RESUME : L'alternance sécheresse-réhydratation des sols entraîne un comportement hydrodynamique particulier des sols argileux et par conséquent des risques de mouvement en masse et d'érosion. Cette étude rentre dans ce cadre et a permis de contribuer à la compréhension de cette dynamique (évolution de l'infiltration, du ruissellement et du phénomène de retrait) par l'utilisation de la simulation de pluie, outil permettant de reproduire sur le terrain les conditions correspondant à une pluie naturelle. Les résultats obtenus ont bien montré l'influence de l'humidité préalable du sol, de l'intensité de la pluie et l'état de surface sur le comportement hydrodynamique. L'écoulement de l'eau dans le sol argileux est de deux types : un écoulement lent (écoulement au niveau de la microporosité du sol) qui se réalise lorsque le sol est humide et fermé (non fissuré) et un écoulement rapide par l'intermédiaire de la macroporosité (écoulement privilégié et hypodermique).
Ce travail de recherche a été consacré à l'étude d'un problème d'actualité, à savoir la pollution... more Ce travail de recherche a été consacré à l'étude d'un problème d'actualité, à savoir la pollution des nappes phréatiques côtières par l'invasion des eaux marines qui s'accentue de plus en plus avec les changements climatiques et l'accroissement de la démographie et des besoins. Sur la nappe côtière d'Alger Est, caractérisée par une exploitation intensive et anarchique, nous avons essayé par une approche pluridisciplinaire, combinant plusieurs méthodes (piézométrique, chimique et géophysique) de mettre en évidence une intrusion marine et de déceler les zones sensibles à la pollution marine dans cette zone côtière et d'analyser les répercussions sur la dégradation des sols par l'utilisation des eaux d'irrigation polluées par la mer. Les résultats obtenus par cette approche ont permis de mettre en évidence une invasion marine et de localiser différentes zones sensibles dans cet aquifère côtier. Les causes principales de ce phénomène sont dues principalement aux pompages intensifs associés au déficit pluviométrique et à la nature lithologique des aquifères. Ces facteurs engendrent une perturbation au niveau de l'interface eau douce-eau salée et accentuent l'avancement des eaux marines vers le continent.
A navegação consulta e descarregamento dos títulos inseridos nas Bibliotecas Digitais UC Digitali... more A navegação consulta e descarregamento dos títulos inseridos nas Bibliotecas Digitais UC Digitalis, UC Pombalina e UC Impactum, pressupõem a aceitação plena e sem reservas dos Termos e Condições de Uso destas Bibliotecas Digitais, disponíveis em https://digitalis.uc.pt/pt-pt/termos. Conforme exposto nos referidos Termos e Condições de Uso, o descarregamento de títulos de acesso restrito requer uma licença válida de autorização devendo o utilizador aceder ao(s) documento(s) a partir de um endereço de IP da instituição detentora da supramencionada licença. Ao utilizador é apenas permitido o descarregamento para uso pessoal, pelo que o emprego do(s) título(s) descarregado(s) para outro fim, designadamente comercial, carece de autorização do respetivo autor ou editor da obra. Na medida em que todas as obras da UC Digitalis se encontram protegidas pelo Código do Direito de Autor e Direitos Conexos e demais legislação aplicável, toda a cópia, parcial ou total, deste documento, nos casos em que é legalmente admitida, deverá conter ou fazer-se acompanhar por este aviso. Impact de la dynamique agricole sur la durabilité des périmètres agricoles traditionnels: cas des oasis des monts du Ksour-Algérie
Stepped spillway is hydraulic structure designed to dissipate considerable kinetic energy because... more Stepped spillway is hydraulic structure designed to dissipate considerable kinetic energy because it's characterised by the large value of the surface roughness. On stepped chutes with skimming flow regime, the flow is highly aerated which can reduce the risk of cavitation. The air entrainment starts where the boundary layer attains the free surface of flow; this point is called “ point of inception ”. In the present numerical study, the Reynolds-Averaged Navier–Stokes equations are coupled with k −e turbulence standard model to simulate the water flow over stepped spillway by using the software Ansys Fluent. Volume of fluid (VOF) model is used as a tool to track the free surface flow. This research aims to find new formulas for describe the variation of water depth and the positions of the inception point. In addition, to study the characteristics of flow over stepped spillways. The found numerical results agree well with experimental results.
The main topics of the extended abstract should fit within the areas of water, energy, climate ch... more The main topics of the extended abstract should fit within the areas of water, energy, climate change, the nexus within water, energy and climate change. The abstract should also be in line with ongoing projects and priorities of the research agenda at PAUWES as a contribution to the Agenda 2063 of the African union.
To assess seasonal patterns of suspended sediment load and its erosiontransport interactions, 17 ... more To assess seasonal patterns of suspended sediment load and its erosiontransport interactions, 17 years of river monitoring data from the Isser River Basin (northwest Algeria) was studied, considering continuous and event-scale approaches. The results show significant differences in sediment yield and transport processes between dry and wet periods. A rate of 8 t ha-1 year-1 was estimated from continuous analysis, with values of 4.3 and 13 t ha-1 year-1 for wet and dry periods, respectively. Estimates of soil delivery ratio pointed to higher values during dry periods and the dominance of hillslope erosion processes. At the event scale, the hysteresis loops confirmed these seasonal patterns in transport dynamics. The calibration of the MUSLE model highlighted the severity of rainfall during the dry period. These results emphasize the importance of seasonality in erosion and transport processes with special relevance in terms of climate change predictions.
This work describes the climate change impact study on rainfall patterns in Macta watershed, loca... more This work describes the climate change impact study on rainfall patterns in Macta watershed, located in the northwest of Algeria. The monthly rainfall data collection, verification and validation have built a database with 42 stations, each with 42 years of observations from 1970 to 2011. The study of annual total rainfall has identified a downward trend and quantifies the deficits that are within the observation time series. The division of the annual rainfall series into four periods allowed to highlighting the increase in inter-year temporal variability with the coefficient of variation increases from 17 to 27%. The study shows an annual rainfall deficit increment from 13 to 25%. The standard deviation values decrease significantly for the last two periods showing a spatial variability. Multivariate statistical study by the hierarchical clustering method resulted in the formation of station groups indicating the unification of monthly rainfall patterns.
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