The Use of the Recession Index as Indicator for Components of Flow

AbstractHydrograph recession analysis is widely used in hydrological research and water resources planning and management. The most common application is the forecasting of low flows, estimating groundwater resources in a catchment, rainfall runoff models and hydrograph analysis. In the rainfall runoff modelling, some authors have included the recession characteristics in their model. They used the recession parameter for hydrograph separation and modelling surface runoff.This paper presents an alternative commonly used techniques for hydrograph recession analysis, namely of an individual recession segment, the master recession and a relatively recent approach based on wavelet transform was carried out in order to separate analytically the linear component hydrographs by recession index K that is commonly used as an indicator of flow. These methods were applied to a set of measures hydrometric the North-eastern Algeria in the watershed Seybouse. The results show that all the methods tested produce reasonable and comparable results

Evaluation des matériaux conducteurs par courant de Foucault pulses

La méthode conventionnelle des courants de Foucault aboutit à des résultats importants. L’inconvénient majeur est sa faible profondeur de pénétration. Pour remédier à cet inconvénient, nous sommes intéressés à utiliser la technique des courants de Foucault pulsés. Cette technique de contrôle est sollicitée dans des secteurs important (nucléaire, aéronautique…). Cette technique de contrôle est appropriée pour sa plus grande pénétration d’analyse et évaluation des structures en multicouche. Elle permet de diagnostiquer différentes couches collées mécaniquement ou empilées en plusieurs couches adhésives. Elle consiste à exciter une sonde avec un signal carré et mesurer la différence de potentiel aux bornes d’une autre sonde. A ce but, notre travail consiste à analyser différents défauts présents dans un matériau conducteur en multicouche. Un système de mesure micrométrique et un système d’acquisition sont réalisés pour établir une cartographie qui caractérise ce matériau

The AVuPUR project (Assessing the Vulnerabiliy of Peri-Urbans Rivers): experimental set up, modelling strategy and first results

International audienceLe projet AVuPUR a pour objectif de progresser sur la compréhension et la modélisation des flux d'eau dans les bassins versants péri-urbains. Il s'agit plus particulièrement de fournir des outils permettant de quantifier l'impact d'objets anthropiques tels que zones urbaines, routes, fossés sur les régimes hydrologiques des cours d'eau dans ces bassins. Cet article présente la stratégie expérimentale et de collecte de données mise en ½uvre dans le projet et les pistes proposées pour l'amélioration des outils de modélisation existants et le développement d'outils novateurs. Enfin, nous présentons comment ces outils seront utilisés pour simuler et quantifier l'impact des modifications d'occupation des sols et/ou du climat sur les régimes hydrologiques des bassins étudiés. / The aim of the AVuPUR project is to enhance our understanding and modelling capacity of water fluxes within suburban watersheds. In particular, the objective is to deliver tools allowing to quantify the impact of anthropogenic elements such as urban areas, roads, ditches on the hydrological regime of suburban rivers. This paper presents the observation and data collection strategy set up by the project, and the directions for improving existing modelling tools or proposing innovative ones. Finally, we present how these tools will be used to simulate and quantify the impact of land use and climate changes on the hydrological regimes of the studied catchments

Mutations et formes d’appropriation de l’habitat rural dans les zones semi-arides

L’étude urbaine et architecturale des espaces consiste à analyser et à comprendre leur dynamisme dans le temps. Par ailleurs, et si l’on veut que cette étude ne manque pas de vitalité et de sens, il est nécessaire, voire primordial de ne pas y éloigner la dimension humaine de la dimension physique de l’espace. Il est évident qu’en suivant, dans le temps, les mutations spatiales d’une agglomération rurale en Algérie, on ne peut ne pas être frappé par le fait que le cadre bâti dans ces agglomérations connues jadis par la diversité et la richesse, est en train de changer perpétuellement et avec des aspects très similaires à travers le milieu rural algérien du Nord au Sud et de l’Est à l’Ouest d’une part, et par le fait que ces changements se convergent généralement vers un modèle unique qui est le modèle urbain et occidental. Les zones semi-arides n’échappent pas à ce constat, et l’agglomération de Lichana à Biskra, peut être un exemple illustratif du phénomène. Néanmoins, ces mutations, ne pouvaient pas exister, si le facteur humain, autrement dit « le paysan » dans le milieu rural, n’a pas connu une métamorphose pas moins importante sur le plan socioculturel, professionnel…..etc En effet, ces transformations qui ont touché et le cadre physique, et le facteur humain de l’agglomération « cadre d’étude », ont forcément induit de nouveaux rapports entre l’espace habité et son habitant. Ce dernier s’est par conséquent, dirigé vers l’appropriation de l’espace de manières qu’il juge à son niveau justes, logiques et adéquates et l’instauration d’une nouvelle façon d’usage et de nouvelles pratiques sociales vis-à-vis de cet espace. Quel serait l’avenir de ces espaces en Algérie, si les choses restent telle qu’elle sont, et si les rapports entre l’« HOMME » et l’« ESPACE » ne se définissent pas par rapport à une perspective architecturale et urbanistique mieux réglementée ?

Climate change impact on rainfall in north-eastern Algeria using innovative trend analyses (ITA)

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 north-eastern 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

Temperature and precipitation risk assessment under climate change effect in northeast algeria

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

Monthly extreme rainfall risk envelope graph method development and application in Algeria

Rainfall patterns are bound to change as a result of global warming and climate change impacts. Rainfall events are dependent on geographic location, geomorphology, coastal area closeness and general circulation air movements. Accordingly, there are increases and decreases at different meteorology station time-series records leading to extreme events such as droughts and floods. This paper suggests a methodology in terms of envelope curves for monthly extreme rainfall event occurrences at a set of risk levels or return periods that may trigger the extreme occurrences at meteorology station catchments. Generally, in many regions, individual storm rainfall records are not available for intensity-duration-frequency (IDF) curve construction. The main purpose of this paper is, in the absence of individual storm rainfall records, to suggest monthly envelope curves, which provide a relationship between return period and monthly extreme rainfall values. The first step is to identify each monthly extreme rainfall records probability distribution function (PDF) for risk level and return period calculations. Subsequently, the return period rainfall amount relationships are presented on double-logarithmic graphs with the best power model as a set of envelope curves. The applications of these methodologies are implemented for three Hodna drainage basin meteorology station rainfall records in northern Algeria. It is concluded that the most extreme rainfall risk months are June, August and September, which may lead to floods or flash floods in the study area. A new concept is presented for the possible extreme value triggering months through the envelope curves as 'low', 'medium' and 'high' class potentials

Parameter Estimation and Assessment of Infiltration Models for Madjez Ressoul Catchment, Algeria

Evaluation and modeling of soil water infiltration are essential to all aspects of water resources management and the design of hydraulic structures. Nonetheless, research focused on experimental studies of infiltration rates in arid and semi-arid regions under unknown boundary conditions remains minimal. This paper investigates the characteristics of the spatial variability of infiltration over a semi-arid rural basin of Algeria. The experiments were conducted using a portable double-ring infiltrometer filled at an equal volume of approximately 100 L of water for each of the 25 catchment locations. Soil moisture contents at the proximity of each test location were evaluated in the laboratory as per the standard NF P94–050 protocol. The experimental results are used to produce the catchment infiltration curves using three statistically fitted infiltration models, namely Horton, Kostiakov, and Philip models. The reliability of the models was assessed using four performance criteria. The statistical regressions of the fitted models suggest that the Horton model is the most suitable to assess the infiltration rate over the catchment with mean coefficients of Nash = 0.963, CC = 0.985, RMSE = 1.839 (cm/h), and Bias = 0.241. The superiority of the Horton model suggests that the initial and final infiltration rates, primarily affected by soil type, initial soil moistures, and land cover, are important predictors of the modeling process over the Madjez Ressoul catchment. The results also infer that the applicability of other models to the different types of undeveloped soils in the study area requires advanced field investigations. This finding will support the understanding of the hydrologic processes over semi-arid basins, especially in advising crop irrigation schemes and methods and managing the recurring flood and drought over the country