M. DOUGHA Mostafa

Climate change and overexploitation of aquifers by
irrigated agriculture and water consumption by the population
caused the decline of water levels and hydrochemical
changes in the aquifer. Our study area is the Maadher plain
which is located in the north-central of Algeria, with an arid
to semi-arid climate. The Mio-Plio-Quaternary aquifer
often shows disordered alternations of sedimentary deposits.
The aquifer is recharged mainly by wadis and drainage
contributions from the Cretaceous and Miocene layers. The
sampling campaign in 2019 based on 13 physicochemical
parameters was carried out on water from 32 boreholes in
the study area, compared to data archives of both sampling
campaign in 1996. Multivariate statistical analyses were
used to identify and know the groundwater origin from
analysis results. Two statistical methods, principal component
analysis (PCA), and hierarchical cluster analysis
(HCA) are applied in order to define the major control
factors that affect the hydrochemistry of Maadher plain. The
results of groundwater samples showed that water is mainly
hard. The order of abundance of major cations exchangeability
for common ions in groundwater was: Ca2+ >
Mg2+ > Na+ > K+ while the major anions reveal an order
as follows SO4
2− > HCO−
3 > Cl− > NO3
−. The Piper
diagram indicates that the hydrochemical facies of sulfate–
chloride–nitrate–calcium (SO4
−2–Cl−–NO3
−–Ca2
+
type water), which globally characterizes the study area,
and these elements are the dominant dissolved ions. It was
noted that the tendency of such groundwater is toward
salinization because the minimum values of total hardness
exceed the WHO standard, which has led to a water quality
between average and poor. A total of 62% of the
groundwater samples exceeded the Ca2+ standard, nearly
65% of the samples exceeded the Cl− standard, and also the
sulfate concentrations were all above health guidelines. The
electrical conductivity values are considerable, and 22% of
the groundwater samples exceed the standard. PCA analysis
showed that the first factors accumulated a percent
variance of 74.22%. The first factor accounts for 40.45%
variance, represented by a large number of mineralization
parameters. The HCA analysis with Q-mode provided
insight into the mineralization of aquifers (Mio-Plio-
Quaternary), so that the main study area can be divided
into three zones of different groundwater quality, with a
total of three factors of control.

Recently, coupled Wavelet transform and Neural Networks models (WANN) were extensively used in hydrological drought forecasting, which is an important task in drought risk management. Wavelet transforms make forecasting model more accurate, by extracting information from several levels of resolution. The selection of an adequate mother wavelet and optimum decomposition level play an important role for successful implementation of wavelet neural network based hydrologic forecasting models.

The main objective of this research is to look into the effects of various discrete wavelet families and the level of decomposition on the performance of WANN drought forecasting models that are developed for forecast drought in the Algerois catchment for long lead time. The Standard Precipitation Index (SPI) is used as a drought measuring parameter at three-, six- and twelve-month scales. Suggested WANN models are tested using 39 discrete mother wavelets derived from five families including Haar, Daubechies, Symlets, Coiflets and the discrete approximation of Meyer. Drought is forecasted by the best model for various lead times varying from 1-month lead time to the maximum forecast lead time. The obtained results were evaluated using three performance criteria (NSE, RMSE and MAE).

The results show that WANN models with discrete approximation of Meyer have the best forecast performance. The maximum forecast lead times are 36-month for SPI-12, 18-month for SPI-6 and 7- month for the SPI-3. Drought forecasting for long lead times have significant values in drought risk and water resources management.

Mécanique des fluides -Cours et exercices corrigés-

Hydraulique appliquée : Ecoulements forcés. Cours et exercices avec corriges
Type de document : texte imprimé
Auteurs : Mostefa Dougha, Auteur
Editeur : Edition El Motanaby
Année de publication : 2022
Importance : 201 p.
Présentation : couv. coul., tab.,fig., phot.,
Format : 27x19 cm
ISBN/ISSN/EAN : 978-9931-865-70-4
Langues : Français (fre) Langues originales : Français (fre)
Résumé : Cet ouvrage résume les notions de base et les formules essentielles sur les écoulements en charge dans les conduites. Il est destiné aux étudiants en sciences et technologies et aux ingénieurs en exercice.
Le livre apporte aux étudiants les notions basées sur les lois de conservation appliquées à un écoulement dans une conduite. il traite la dynamique des fluides incompressibles en écoulements permanents.
Les chapitres de cet ouvrage traitent des écoulements sous pression, des pompes et donc du dimensionnement des réseaux hydrauliques en illustrant l'application de la théorie sous-jacente à un large éventail de situation pratiques. Des exercices avec leurs réponses permettent aux étudiants d'évaluer leur compréhension de la théorie et des méthodes d'analyse et de conception.
accompagné de près de 60 exercices avec des corrections détaillées sur des applications pratiques intéressantes qui en font une bonne préparation aux examens, aux concours et à l'aventure professionnelle.

This study focused on water quality and hydro-geochemical processes (evolution, origin) in the Maadher region, central Hodna in Algeria. In recent decades, the excessive exploitation of this resource due to urbanization, irrigation, and the effect of climate change reaching the countries of northern Africa have caused a decline in water levels and hydrochemical changes in the aquifer. The sampling campaign in 2019 based on 13 physicochemical parameters was carried out on the water from 32 boreholes in the study area, compared to data archives of both sampling campaigns in 1967 and 1996. The result revealed that the groundwater as a whole has moderate freshwater quality, due to its total dissolved solids (TDS) content and other dissolved ions of concern (nitrate NO3−), which exceed WHO standards. In addition, Piper diagram indicates that the hydrochemical facies of sulfate–chloride–nitrate–calcium (SO42−–Cl−–NO3−–Ca2+ type), which globally characterizes the study area and these elements are the dominant dissolved ions. Principal component analysis and hierarchical cluster analysis (HCA) methodologies are applied in order to define the major control factors that affect the hydrochemistry of Maadher plain. Three distinct water groups were found, illustrating a different evolution of salinity (EC and TDS). The HCA indicated an interesting cluster with a distinct contamination signature and most likely with significantly higher sulfate, chloride, and nitrate concentrations. Anthropogenic processes also play an important role in the study area. The water resource comes from Bousaada Wadi, the exchange at the aquifer depth and the agricultural practices contribute to the deterioration of the quality.

In a semi-arid region of Maadher, central Hodna (Algeria), groundwater is the main source for agricultural and domestic purposes. Anthropogenic activities and the presence of climate change’s effects have a significant impact on the region’s groundwater quality. This study’s goals were to use water quality indices to evaluate the groundwater’s quality and its suitability for drinking and irrigation, as well as to identify contaminated wells using a geographic information system (GIS) and the spatial interpolation techniques of ordinary kriging and inverse distance weighting (IDW). The results reveal that all water samples exceeded the World Health Organization’s standards for nitrate ions and had alarming concentrations of calcium, chlorine, and sulfate (WHO). According to Piper’s diagram, the groundwater hydrochemical facies is composed of the elements sulfate–chloride-nitrate-calcium (SO42−-Cl—NO3−-Ca2 …

The change of climate and intensive exploitation of groundwater resources in the plain of M'sila has influenced the hydrochemical functioning of the complex aquifer. This resulted in a decrease in the piezometric level of groundwater. The multivariate statistical techniques were used to determine the main factors and regrouping parameters/wells and to understand the origin of groundwater chemistry. Multivariate analysis (principal component analysis and cluster analysis) was performed to identify a common source for sampling data of a semi-arid aquifer. Physicochemical analyses were conducted on the waters of 17 wells. The chemical water classification shows the dominance of a chlorinated calcium and magnesium sulphate type facies, which has a very remarkable tendency towards the salinisation. Cluster analysis based on major parameters contents defined four main chemical water groups with increased water-rock interaction. Some parameters presented the highest concentrations of the total of dissolved salts provoking a poor quality of water.

A numerical study of hydrodynamic behaviour in swimming pools was conducted to control the water quality. Hydrodynamics and mass transport processed by Computational Fluid Dynamics (CFD) were compared with experimental measurements of the residence time distribution (RTD). A CFD tool with turbulence models and a transport model of a species used to find the hydrodynamic effect on water quality by limiting the water dead zones that prevent the arrival of the disinfectant and that favour the development of micro-organisms. In addition, the hydrodynamic behaviour was determined experimentally by a pulse tracer test to compare the RTD. This work describes the hydrodynamic behaviours of three pools. The models are suitable for the study of physical and chemical phenomena with long characteristic times. The purpose of this article is to present the influences of hydrodynamic behaviour on the water quality, which in turn is influenced by design and hydraulic exchange conditions. In general, the result of this research underlines the hydrodynamic behaviour importance for a better water quality in a swimming pool. The next part of the project will focus on chemical and biological transformation processes.

Abstract: The recent studies on the climate change vulnerability in the arid and semiarid regions show a trend
to increase the aridity, which accelerates erosion. This complex and aleatory phenomenon is dependent in
addition to the anthropogenic factor on some natural parameters, especially, the hydro-climatic forcing, the
topography, the geology and the land use. This study aims to analyze and map the erosion sensitivity of Hodna
basin in the central of Algeria with an area of 26000 km². It is the fifth basin of Algeria, located at 150 km to the
south of the Mediterranean coast. The erosion sensitivity mapping approach is based on a multi-criteria method
of the parameters of topography, the geology and the land use with a hydro-climatic forcing parameter
represented by the precipitation. The analysis of the maps obtained under GIS environment for different criteria,
shows that the findings vary from one criterion to another. However, taking all criteria into account, the
obtained map shows that the areas with a high vulnerability to erosion are located in the south and the west
of the basin, representing 25% of the total basin area.