English Larhyss journal is an international peer-reviewed journal published by the research laboratory in subterranean and surface hydraulics since 2002. The scope of the Journal covers the fields in which the teams of the research laboratory in subterranean and surface hydraulics are active. Original research papers, short communications and critical reviews from all fields of science and engineering related to water are welcomed. Larhyss journal is devoted to the rapid publication of research in water engineering, acting as a link between the diverse research communities and practitioners in the field of hydraulics. The journal accepts manuscripts in English preferably or in French exceptionally and publishes abstracts in both official languages. Larhyss journal publishes articles on all aspects of hydraulics including hydrology, water and wastewater treatment, surface, and groundwater protection, flow in channels, and pipes, hydraulic modeling… Français LARHYSS journal est une revue scientifique internationale publiée par le laboratoire de recherche en hydraulique souterraine et de surface depuis 2002. La portée du Journal couvre les domaines dans lesquels les équipes du laboratoire de recherche en hydraulique souterraine et de surface sont actives. Des documents de recherche originaux, des communications brèves et d'analyses critiques de tous les domaines de la science et de l'ingénierie liées à l'eau sont les bienvenus. LARHYSS Journal est consacré à la publication rapide de la recherche en ingénierie de l'eau, agissant comme un lien entre les communautés de recherche diverses et praticiens dans le domaine de l'hydraulique. La revue accepte des manuscrits en anglais préférentiellement ou en français exceptionnellement et publie des résumés dans les deux langues officielles. LARHYSS journal publie des articles sur tous les aspects de l'hydraulique, y compris l'hydrologie, le traitement des eaux, la protection des eaux souterraines et de surface, ecoulements dans les canaux et conduites, modelisation hydraulique...








Lahmar Karim,  Saied Sawssen,  Majdoub Rajouane,  Larue Jean- Pierre,  Ballais Jean- Louis, 

Résumé: The degradation of water quality and the competitive exploitation of this resource are accelerating, especially in the Mediterranean region. Climate change accentuates the phenomenon of water scarcity which is itself catalyzed by a marked degradation of resources. In order to produce an image of the runoff water quality of the Cesse watershed, located in the South-East of France, a method is proposed that combines a geo-environmental and cartographic study. Results and the mapping of the physico-chemical analyzes of the waters of the Cesse showed that the transfer of chemical facies occurs from upstream to downstream. High concentrations are often found at the outlets of rivers and tributaries. Interpretation of obtained results revealed the origin of the strong mineralization. The geology and hydrology of the study area explain the spatial variations. The experiment errors are negligible. The mapping by interpolation fills some gaps in the values obtained. The technique adopted reflects a better representation of certain processes, in particular Upstream / Downstream communication in the same watershed. That is, the concentrations of chemical elements in the samples change in relation to the morphology and hydrology of the watershed. This could improve the existing database in particular for the hydrological conditions of the small watersheds of the Mediterranean.

Mots clés: The Cesse Watershed; cartography; chemical facies; evolution.


Dbara Soumaya,  Lahmar Karim, 

Résumé: Nowadays, climate change scenarios predict a rainfall irregularity, which poses the problem of water resources scarcity. The use of unconventional water and in particular treated wastewater in agriculture is one of the adopted remedies. This work studies its impact on soil characteristics. Results showed a slight increase in pH and electrical conductivity which can interfere with the uptake of minerals by plants. As for the content of organic matter and mineral elements, the richness of water in these elements increases it. Likewise, the heavy metal content always remains low and below the standards for the various sites. So, this water can be used in agriculture with regular monitoring of soil characteristics which is recommended.

Mots clés: treated waste water ; irrigation ; soil ; heavy metals


Nassa Relwindé Abdoul-karim,  Kouassi Amani Michel,  Bossa S. Judith, 

Résumé: The objective of this study is the analysis of the sensitivity of the statistical This study focuses on the analysis of the sensitivity of the statistical models of extremes according to the climatic context. It was based on annual maximum daily rainfall data and annual rainfall data collected over the period 1931-2010 from twenty-six (26) rainfall stations in Ivory Coast. The methodological approach is based on the one hand on the characterization of the climatic context based on annual rainfall. On the other hand, the approach of frequency analysis of extreme rainfall was adopted. The results of the climatic characterization highlighted two periods namely a wet period before 1970 (1931-2010) and a dry period after 1970 (1971-2010). It is found that the wet period is dominated by the models of Gumbel (54%), Gamma (19%) and exponential (11%). As for the dry period, it is dominated by the inverse Gamma (38%), Gumbel (35%) and Gamma (23%) models. The different statistical models of extremes are therefore sensitive to the climatic context of the data. These results raise the problem of hydrological norms calculated from the quantiles of the models of extremes in a current context of climate change.

Mots clés: Changements climatiques ; Sensibilité des lois ; Analyse fréquentielle ; Côte d’Ivoire


Achour Bachir,  Amara Lyes, 

Résumé: The rectangular weirs with and without lateral contraction are theoretically examined, more particularly their discharge coefficient. Under the realistic assumption of a critical state at the location of the weir, the application of the energy equation between two judiciously chosen sections, while taking into account the effect of the approaching flow velocity, leads to a third-degree equation. The analytical solution of the equation shows that the discharge coefficient is a function of both the relative height of the weir and the rate of contraction. This is what the relationships drawn from the experiment reveal. It was easy to deduce the discharge coefficient of the rectangular weir without lateral contraction by writing that the contraction coefficient is equal to unity. The theoretical relationship of the discharge coefficient is compared to the experimental tests abstracted from the literature and is corrected consequently to be in conformity. Also, a comparison is made with the recognized experimental relationships proposed by some research workers and good agreement is observed.

Mots clés: Rectangular weir ; contracted weir ; suppressed weir ; discharge coefficient ; lateral contraction


Achour Bachir,  Amara Lyes, 

Résumé: The study deals with the thin-plate triangular notch weir as a flow measurement device. Unlike previous studies on this subject, a theoretical development is proposed which takes into account the effect of the approach flow velocity. Between two well-chosen sections, the energy equation is applied with certain simplifying assumptions 1) the head loss and the effect of both viscosity and surface tension are neglected, 2) Assuming a hydrostatic distribution of the pressure. 3) The effect of the flow streamlines curvature over the weir is neglected. All the parameters influencing the discharge coefficient are well defined in the theoretical equation, as the experiment predicts so well. The theoretical equation of the discharge coefficient is adjusted to be in conformity with the experimental data. The adjusted relationship is a function exclusively of the relative weir height ratio P/h1 and dimensionless number , where m is the side slope of the notch, i.e. m horizontal to 1 vertical, h1 corresponds to the upstream water depth measured above the vertex of the notch, and B is the width of the rectangular channel of approach. The corrected theoretical relationship causes a maximum deviation of 6% on the calculation of the discharge coefficient, knowing that the average relative error is less than 1.88%. It is worth noting that among the 168 calculated values of the relative deviation on the computation of the discharge coefficient, 94% are less than 5% meaning that 6% only are greater than 5%, 87% are less than 4% , while 76.2% are less than 3%.

Mots clés: V-notch ; weir ; discharge coefficient ; weir height ; approach velocity


Achour Bachir,  Amara Lyes, 

Résumé: The study is devoted to the parabolic-shaped thin-plate weir. It is the flow coefficient which is of particular interest to the study. This is planned to be determined from a theoretical point of view using the energy equation. This is applied between two well-chosen sections, the first of which is located in the channel of approach upstream of the weir and the second is considered at the location of the weir. The state of the flow over the weir is subject to the realistic assumption that it is critical. Other simplifying assumptions are adopted such as the head loss which is neglected between the chosen sections, or that the pressure is not considered to be hydrostatic. The effect of the curvature of the flow streamlines above the weir is also neglected. The strength of the theory lies in the fact that the approach flow velocity is taken into consideration. Taking into account all the simplifying assumptions made during the study, it is obvious that the theoretical discharge coefficient must be different from the experimental discharge coefficient. In order to correct the deviation observed between these two discharge coefficients, experimental tests available in the literature are used. The corrected theoretical discharge coefficient relationship was established on the basis of 157 significant measuring points, giving rise to an average error of less than 1.3% on the discharge coefficient calculation, while the maximum deviation is of the order of 6%. It is worth noting that 92.85% of the calculated values of the deviation are below 3%, meaning that 7.15% only are greater than 3%, while 82.5% are less than 2%.

Mots clés: Parabolic weir ; discharge coefficient ; channel of approach ; approach velocity.


Achour Bachir,  Amara Lyes, 

Résumé: The study proposes a theoretical development in order to determine the relationship which governs the discharge coefficient of a contracted triangular weir. The theoretical approach takes into account the effect of the approach flow velocity which can be considered as a novelty in comparison with previous studies. The theoretical development consists in applying the energy equation between two well chosen sections with certain simplifying assumptions, namely: i) the head loss and the effect of both viscosity and surface tension are neglected, ii) the hydrostatic distribution of the pressure is considered hydrostatic, iii) the effect of flow streamlines curvature over the weir is neglected. The first section chosen is located in the supply channel at a certain distance upstream of the weir, while the second section corresponds to the location of the weir supposed to be crossed in a critical flow regime. Based on the data available in the literature on the 90 ° opening angle triangular weir, the experimental and theoretical discharge coefficients are compared and relative errors varying between 4% and 10% are observed. The theoretical discharge coefficient relationship is thus adjusted to be in conformity with the experimental data relative to this apex angle. The corrected theoretical relationship causes a maximum deviation of 1.5% on the calculation of the discharge coefficient, but this error is observed only for the ratio P/ B = 1. For the other values of P/B, the maximum error varies between 0.35% and 1.3%, where P is the weir crest height and B is the width of the rectangular channel of approach.

Mots clés: 90° V-notch ; weir ; discharge coefficient ; weir crest height ; approach velocity.


Amara Lyes,  Achour Bachir, 

Résumé: A novel theoretical approach for the flow discharge relationship in circular sharp crested weir is developed in the present paper. Based on the application of the energy equation applied between a section taken in the approach channel and the weir under critical flow conditions, a general stage-discharge relationship is obtained taking account width contraction effect and kinetic energy in the approaching channel. A correction function is introduced to take into account the simplifying assumptions assumed in the theory such as the non-consideration of viscous effects, the curvature of the streamlines due to the contraction of the weir and the surface tension. Derivation of the discharge coefficient expression for classical stage-discharge equation is also given. In order to check the proposed model, verification with laboratory measurement data available in literature are made. Results show a very good agreement between predicted and actual discharge.

Mots clés: Circular weir ; Stage-discharge equation ; Discharge coefficient ; Approach velocity


Brakeni Abderrezak,  Guryev Alim Petrovic,  Chumicheva Marina Mikhailovna,  Mareeva Olga Victorovna,  Verhoglyadova Alexandra Sergeevna, 

Résumé: The stability of a rectilinear axis dissipator can be evaluated on the basis of the study of the hydrodynamic forces, in terms of pressure and pressure fluctuation acting on the raft downstream. This article analyzes the operation of existing designs of devices for dissipating excess energy from water discharges with regard to the hydraulic structures. The simplest and most widely used design for dissipating flow energy are straight-axis, prismatic or trapezoidal stilling basins, but the main drawback of the latter is high material consuming and the requirement for ensure a uniform distribution of unit flows in the inlet section, which makes them ineffective for circular bottom spillways. A new model is proposed in this article with the aim of minimizing the agitation of the stilling basin flow in the form of a spiral by shortening the length of the basin, and simultaneously creating the possibility of a planned intensive spreading of flow in the outlet section of the water basin, allowing it to be used when a multiple widening of the flow behind the spillway is required. This model not only promotes a more stable flow in the area near the dissipator, but also dissipates the energy of streams with any hydraulic characteristics.

Mots clés: Enlarged dissipation basin ; flow disturbance ; energy dissipation ; swirling flow, ; excess flows