Résumé: Any hydro-meteorology variable includes different components, in general, such as periodicity, trend, possibly jump, and uncertain stochastic parts. Among these, the trend analysis gained importance in the last three decades due to global warming and climate change effects. The literature is full of monotonic trend applications by taking into consideration trend analysis methodologies such as Mann-Kendall trend identification, Sen trend slope calculation, and Şen innovative trend analysis (ITA). It is more important in practical studies to deal with less than one-year durations to assess the possible trend pieces for better practical uses such as agricultural productivity purposes. In this paper, a new concept is applied, known as the innovative polygon trend analysis (IPTA), to assess the trend component transitions between two successive months. The application of the methodology is presented for the coastal region of northeast Algerian precipitation records. The emanated results from this study provided information that El Taref station has the most unstable precipitation behavior among all the meteorology stations in the study area, moving from a month to another rather very unsystematically; whereas other meteorology stations have systematic movement from a month to the subsequent one.

Résumé: Climate change impacts affect the hydrological cycle and hence the availability of water resources and their management. Rainfall, the most important hydro-meteorological event and as the main source of water, may have increasing or decreasing trends depending on geography and location, general air circulation, proximity to coastal areas, and geomorphology. There are many studies using monotonic trend analysis in the literature, but it is important to assess these trends at different levels for proper recording. For this purpose, in this paper, instead of using monotonic trend analysis, partial trends will be sought at "Low," "Medium," and "High" rainfall records groups, which is possible through the innovative trend analysis (ITA) methodology. Algeria being adjacent to the Mediterranean Sea is impacted by variations in rainfall. The application of the ITA methodology is presented for 16 different Algerian annual rainfall records from 1982 to 2019 in the northeastern region of the country which is in proximity to the Mediterranean basin. Partially increasing, decreasing, or no trend pieces are identified at each station. It is concluded as the future unfolds some stations will record dry spell or drought dangers for "Low" data groups, and significant flood danger for the "High" rainfall amount data group. In general, the study area is known to be subject to an increasing rainfall trend. This is due to the mountainous terrain in the study area and makes for confrontation with cold air movements from the European continent during winter periods.

Résumé: Climate change impacts on social, economic, industrial, agricultural, and water resource systems tend to increase incrementally with each passing day. Therefore, it is necessary to plan to control its effects, especially with regard to temperature and rainfall events impacting future water resource operation, maintenance and management works. Climate change has a direct influence at the trend of both components temperature and precipitation in increasing or decreasing manner depending on the study area. This paper presents and interprets temperature and rainfall trends for Northeast Algeria. A trend analysis technique was employed along with risk assessment. The modified risks associated with 2-, 5-, 10-, 25-, 50-, 100-, 250, and 500-year return periods are then calculated for each station. This methodology has been applied to precipitation and temperature records for six different meteorological stations in Northeast Algeria. This study confirms that climate change has and will continue to have an impact on temperature and precipitation that should be considered for all infrastructure planning, design, construction, operation, maintenance and optimum management studies in future.

Résumé: L’eau est une ressource indispensable à la survie de l’Homme, or l’Homme par ces activités contribue à sa dégradation, hypothèque ainsi sa disponibilité et limite son utilisation pour les générations futures. La ville d’Annaba est parmi les villes les plus industrialisées de l’Algérie et parmi celles les plus peuplées aussi, les industries qui rejettent les eaux usées en général sans traitement préalable dégrade la qualité des cours d’eau et mettent en danger la vie de populations riveraines. Par notre travail nous avons voulu contribuer modestement pour mettre à la disposition des institutions qui se préoccupent de ce volet de pollution des cours d’eau et particulièrement OUED MEBOUJA qui reçoit des eaux usées d’origine industrielle et urbaine un modèle mathématique qui permet de ressortir la corrélation existante entre les différents paramètres et de différencier une zonalité de la qualité de l’eau dans la région étudiée ceci en utilisant la méthode ACP (analyse en composantes principales) qui est un puissant outil d’aide à la décision, en effet une interprétation efficace et rapide des résultats est d’un rapport considérable quand il s’agit de mettre en place des plans d’action pour pallier à ces problèmes de pollution des cours d’eau. Les zones industrielles concernées par cette recherche sont Z.I El Hadjar, Z.I Meboudja et Z.I Pont Bouchet. Après l’interprétation des résultats on a trouvé que 74% des points de rejet sont caractérisés par une forte concentration de fer et faible concentration pour les autres élément du fait de la corrélation négative, une zone médiale composée de 04 point de rejets présente des concentration moyennes de la plupart des élément néanmoins une teneur élevée en azote et en matière en suspension est localisée pour l’industrie du transport et ces services, par ailleurs pour un seul point de rejet celui juxtaposant l’entreprise LINDE GAZ industriel l’eau est riche en chlorure et en phosphore, ainsi que des matières organique expliqué par la nature de cette industrie pour les deux premier et sans doute pour une absence de traitement des eaux usées pour le deuxième, ces éléments ne sont pas transportés vers les autres région du OUED. L’ensemble des résultats montrent que les eaux d’OUED MEBOUJA présentent des signes de dégradation selon la nature de chaque zone et de chaque industrie, la préservation des ressources hydriques devient donc impérative devant la dégradation des écosystèmes aquatiques et exige la mise en place de solution de dépollution spécifique pour chaque zone sus déterminée.

Résumé: Algeria is among the semi-arid countries highly vulnerable to climate change, have experienced a period of very severe droughts with annual average temperature increases ranging from 0.65 ᵒC to 1.45ᵒC between 1970 and 2004, an average comparable to the global average increase observed over the period between1906 and2005 (Bessaoud, 2008). In this study, a new simple and effective approach developed by (Şen, 2012) is suggested with statistical significance test for trend identification in an innovative manner applied to detect the trends in the annual precipitation and temperature for Bejaia city situated north region of Algeria in order to see if there are any significant changes for the period between 1982 and 2017.

Résumé: The primary factor of climate change impact is due to trend components in increasing or decreasing manner depending on the study area over the world. This paper presents temperature and rainfall trend identification and interpretation works in Bejaia city, Algeria. For this purpose, trend analysis technique is employed along with risk assessments. The modified risks associated with 2-years, 5 years, 10-year,25 years, 50-year,100-years, 250-years, and 500-year return periods are calculated. the application of the proposed methodology is given for precipitations and temperatures records.