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Open access

Ali Brahmia, Nafaa Brinis and Tahar Nouar

Abstract

This work was conducted on 23 samples distributed between springs, wells and boreholes tapping the shallow and deep aquifer in the M’Daourouch-Drea area located in extreme northeast of Algeria. Ca2+, Mg2+, Na+, K+, Cl, SO4 2−, HCO3 and NO3 were analysed. The interpretation of the geological-geophysical data allowed us to highlight two aquifers. The first consists of conglomerates, sandstones, gravels, sands, marls, limestones, lacustrine and alluvial deposits varying in thickness from a few tens to a few hundred meters, representing Neogene-Quaternary filling of the studied basin. The second is more important localized in the cracked and karstified limestones of upper Cretaceous age; these limestones are outcropped on the flanks of the syncline and the borders of the basin. The first aquifer sometimes rests directly on the second which allows hydraulic communication between them. The hydogeochemical and statistical study, with the combination of numerous tools, indicates that the chemistry of groundwater in the M’Daourouch-Drea Plain is controlled both by the dissolution of the minerals of the evaporite formations and those of the carbonate formations.

Open access

Leszek Dawid

Abstract

At the end of 2016 there were 84 wind farms under construction in 11 European countries. Investments in this sector are enormous. The average cost of a wind farm construction amounts to approx. 4 mln EUR per 1 MW of installed power. Offshore wind energy production also plays a significant role in the process of ensuring energy security in Europe, and in reduction of greenhouse gases. The objective of this paper is to present prospects of offshore wind energy farms development in the leading member states of the European Union as regards this problem. In this paper offshore wind farms in Germany and Denmark have been studied. In the paper the power of wind farms, the support systems as well as criteria related to location of wind farm offshore have been analysed. German and Danish sectors of offshore wind energy are strongly supported by respective governments. Both countries aim at yearly increase of wind energy share in total energy production. The research has been conducted based on the analysis of acts, regulations, the subject’s literature and information from websites.

Open access

Lily Montarcih Limantara, Donny H. Harisuseno and Vita A.K. Dewi

Abstract

Analysis of rainfall intensity with specific probability is very important to control the negative impact of rainfall occurrence. Rainfall intensity (I), probability (p) and return period (T) are very important variables for the discharge analysis. There are several methods to estimate rainfall intensity, such as Talbot, Sherman, and Ishiguro. The aim of this research is to develop equation model which can predict rainfall intensity with specific duration and probability. The equation model is compared with the other methods. The result of rainfall intensity model with the value of correlation >0.94 and Nash–Sutcliffe coefficient >99 is quite good enough if compared with the observation result. For specific return period, the modelling result is less accurate which is most likely caused by election of duration. Advanced research in other location indicates that short duration gives the better result for rainfall intensity modelling, which is shown by the decreasing average value of mean absolute error (MAE) from 12.963 to 8.26.

Open access

Rabia Malkia and Salim Etsouri

Abstract

The objective of this work is to determine the effects of climate change on the water needs of crops in the Bounamoussa perimeter, which is one of the large irrigation systems in the North-East of Algeria in order to predict a diagnosis of its operation. This region covers an area of 16,500 ha and is specialized in vegetable production.

The climatic trend of recent years in the study area is characterized by increasingly severe drought conditions that have compromised agricultural production at this perimeter. In this study, the results of the climatic parameters projected to 2050 and 2080 under the Climate Wizard program were used in the CropWat 8.0 program for estimating the future water requirements of crops, taking into account the three Scenarios (B1, A1B, A2) of greenhouse gases (GHGs). The Decision Support System for Agrotechnology Transfer (DSSAT) 4.5 program has also been used to generate future climatic parameters (temperatures and rains) to be compared with those of the climate wizard. The results obtained in 2050 and 2080 show a trend towards increasing temperatures and a fall in rainfall for all models and that the water requirements will be multiplied by 3 to 5 times the current needs. This situation will cause an imbalance in the operation of perimeter irrigation systems. Among the measures of adaptation to this situation in the first place is the change of the date of planting after calibration of the two models for all the cultures of the perimeter.

Open access

I Wayan Yasa, Mohammad Bisri, Moch Sholichin and Ussy Andawayanti

Abstract

Hydrological drought index analysis has been widely developed and applied for the development of water resources. The island of Lombok, which is largely a dry land, requires a significant hydrological drought index to be sourced from measurable data analysis. This research focused aims to obtain hydrological drought index in Lombok Island using the capacity change of reservoir. The analysis includes reservoir data especially in the event of El-Nino. The main parameters analysed in this work are data homogeneity, decrease line of reservoir volume, increase in the line of reservoir volume, reservoir volume deficit, and hydrological drought index (RDI). The basic equation uses the water balance in the reservoir, which is the inflow–outflow and change of reservoir. The results of the analysis show that in the event of El-Nino, the drought hydrological index indicates different levels depending upon the water level of the reservoir. The criteria for the drought level are as follows: weak RDI = from −0.46 to −0.01 at an reservoir elevation of 90.88 to 92.33 m a.s.l, moderate RDI: from −0.59 to −0.46 at water level of reservoir from 90.27 to 90.88 m a.s.l, sever RDI: from −0.80 to −0.59 at water level of reservoir from 88.83 to 90.27 m a.s.l. and very severe RDI: from −0.89 to −0.80 at water level of water reservoir 87.78–88.83 m a.s.l. The duration of drought was 9 months, i.e., from February to November.

Open access

Sihem Hedjal, Derradji Zouini and Abdelwaheb Benamara

Abstract

The wetland complex of Guerbes-Sanhadja (north-eastern Algeria), has experienced in recent years a certain economic expansion, particularly agricultural, about 47% of the useful agricultural area marked by several varieties of crops ranging from market gardening to speculative crops, requiring large quantities of water for irrigation purposes, however the swampy areas are the main sources used for irrigation purposes in this practice. It is therefore necessary for this water to have physicochemical properties adapted to plants, in particular the absence of salinity. This study was done to evaluate the status of the swamps areas quality and its suitability for irrigated agriculture. To achieve this objective, water samples from ten swamps areas water were collected from Guerbes-Sanhadja in February and June of 2016. The water quality of these swamps was estimated from different water quality parameters such as pH and electrical conductivity (EC), the chemical parameters like Na+, K+, Ca2 +, HCO3 , SO4 2−, Cl, BOD5, NO3 , NO2 , NH4 + and PO4 3−. Based on the physico-chemical analyses, irrigation quality parameters like sodium absorption ratio (SAR), percent sodium (% Na), residual sodium carbonate (RSC), permeability index (PI), magnesium hazard (MH) were calculated. The results showed that the overall concentration of nitrate was very high. About 60 percent of the swampy areas had suitable water quality for chloride, and they had a concentration below the permissible limit for crop irrigation. From the Richards diagram, it is observed that most of the samples from the study area fall in the good to permissible classes for irrigation purpose.

Open access

Nargis Sahib

Abstract

This work aims to review the existing theoretical literature and experiments on plant species colonising gaps after soil disturbance. It attempts to evaluate the various mechanisms by which plants regenerate among the soil openings within the Mediterranean temporary ponds. Intensity and frequency of disturbances are key factors in the response of communities. Knowing the specificity of plant strategies and the species assembly process is important for a better understanding of the impact of soil disturbance on the structure of temporary ponds community, and their mechanisms of resilience. Under the scope of these mechanisms, we will assess the contribution of seed bank by regrowth of buried seeds, vegetative propagules growth via clonal propagation and dispersion of propagules. Soil disturbance has a biotic effect on competition giving a chance to competitively inferior species.

Open access

Gabriel Minea, Georgiana Tudor, Florentina-Iuliana Stan, Gabriela Ioana-Toroimac and Raluca Zamfir

Abstract

Taking into account the well-established influence of hillslopes grasslands on runoff processes, the purpose of this study was to investigate how grasslands can affect the water flow pathways on hillslopes, in drought conditions. This study was performed in experimental grassland at plot-scale (e.g., Festuca pratensis), in temperate humid continental climatic conditions of Curvature Subcarpathians, Romania. The rainfall, evapotranspiration, and soil moisture daily data, respectively 208 rainfall and 16 rainfall-runoff events data measured in grassland hills during the growing season (1 April up to 30 September 2015 and 2016) were used. Our results suggest that a runoff event response in extreme drought conditions occurs on grasslands only if precipitation exceeds the threshold of 31 mm Hortonian overland flow (HOF), while this threshold drops to 17 mm during moderate droughts and up to 8 mm for wet conditions. The rainfall events up to 16 mm proved to be insufficient to completely saturate the soil. Therefore, HOF has only a minor contribution in drought conditions, on grassland and light on bare soil. A complementary and negative effect of grasslands in drought conditions is the water resources suppressing on hillslopes.

Open access

Faiza Lallam, Abdesselam Megnounif and Abderrahman Nekkache Ghenim

Abstract

The runoff coefficient (RC) is a parameter that is very often used in surface hydrology in order to characterize the drainage capacity of a watershed. The traditional estimate of this coefficient is often made from abacuses based on 2 or 3 parameters to the maximum. In this work, three numerical models are presented. Two models are based on experimental work. The first one is based on three criteria, namely the vegetation cover, the type of soil, and the slope. The second one considers the size of the watershed, the maximum daily rainfall and the type of soil. In practice, it is not easy to estimate the coefficient of runoff by simultaneously considering the influence of several criteria. In order to overcome this problem, a third model is developed and presented; it allows capitalizing the information from the first two models mentioned above. The objective of the present work is to be able to verify the comparability of these criteria and to assess the relative importance of each of them.

Open access

Mohamed A. Bensoltane, Lotfi Zeghadnia, Lakhdar Djemili, Abdalhak Gheid and Yassine Djebbar

Abstract

The drinking-water supply sector has mostly targeted the water-borne transmission of pathogens. The most common method employed is the chlorination of drinking-water at treatment plants and in the distribution systems. In Algeria, the use of chlorine in drinking water treatment is a widespread practice. To enhance the concentration of the residual chlorine in the public water-supply system of a part of Souk Ahras city (Faubourg) (Algeria) known by its low concentration of the free residual chlorine (according to the water utility – Algérienne des Eaux: ADE investigation) especially at the point of use, practical steps were carried out. The method is a combination between numerical simulation using EPANET2 software and field measurements. Using statistical analysis the hydraulic model was calibrated and the observed values were very closer to the simulated results. The concentration was improved throughout the network after the injection of the appropriate dose.