LARHYSS Journal

10

Authors: ADJIM M., BENSAOULA F.

Mapping the vulnerability of ground waters in regions of high anthropogenic actions is a crucial step in any realisation in order to ensure rational management of water resources as well as a harmonious urban and socio-economical development. The present work aims at the determination of vulnerable areas of one of the most important aquifer in the north western region of the “wilaya” (department) of Tlemcen. Indeed, this important aquifer of Maghnia which encroaches on the Moroccan territory is increasingly used by farm operators. It is formed by alluvial and clayey sand formations of Plio-Quaternary. Water pumping in this region is realised by means of classical wells (the most widely used method) as well as by drillings. Unlike wells, the drillings can capture all the water, which may results in an intensive exploitation of the aquifer. In this paper, we used the DRASTIC method to obtain the mapping of the intrinsic vulnerability of this aquifer. The results clearly indicate two vulnerable areas. This map constitutes an important basis for the integrated groundwater management studies and the long-term planning of protective measures. Keywords: Map of vulnerability, pollution, groundwater protection, Drastic, aquifer of Maghnia.

13

Authors: MORRI M., DAGHARI H.

In Tunisia, saline soils occupy an area of 1,5 million hectares, roughly 25% of the total area of arable land in the country. The irrigated area of Kalâat EL Andalous, is a part of this environment and already characterized by low yields. The present work aims to quantify the dose of salt leaching and verification of its effectiveness to predict the risk of salinity on the soil and on plants. The measured of leaching dose is about 1100 m3/ha, close to the theoretical value determined by the formula of Rhoades. A quantity of salts made by the irrigation water is about 15 t / ha, the amount of leached salt is about 9 t / ha. The amounts of salt accumulated in the root zone during the irrigation season is 6 t / ha. Keywords: Salinity, irrigated area, Kalâat El Andalous, leaching dose, drainage.

14

Authors: DOUBI M., DERMAJ A., AIT HADOU B., CHEBABE D., ERRAMLI H., HAJJAJI N., ABDELLAH SRHIRI A.

The study concerns the analysis of physico-chemical parameters (temperature, pH, E.C, NO3, Cl, PO43-, HCO3, SO4, Ca, Mg) of water of Moulouya river and its tributary "Chog Wadi Al Ard" in order to establish a diagnosis of pollution degree of the river waters in study area. Thus, water samples were carried out at six stations in two different seasons in order to establish a comparison between a dry period and during floods. The analytical results obtained during the study period, show that water stations present calcium bicarbonate and magnesium character. The parameters studied during like the temperature, hydrogen potential, conductivity, alkalis, alkaline, sulphate, chloride show that in general the obtained values a good quality. Results of nitrate and orthophosphate analyses give very low values in accord with few “fertilizer and pesticide agricultural treatment”. Keywords: physico-chimical quality, Low flow, Flood, Moulouya river, Oued Chog al ard.

18

Authors: KOUASSI A.M., KOUAME K.F., SALEY M.B., BIEMI J.

The objective of this study is to evaluate the impacts of climate change on groundwater resources of crystalline and crystallophyllian basement aquifers. This study was applied to the particular case of N'zi-Bandama watershed in Ivory Coast. This catchment lies between longitudes 3°49' and 5°22' West and latitude 6°00’ and 9°26' North and covers an area of 35,500 Km2. It belongs to three climatic regimes that are from North to South, the tropical transition regime, the humid tropical regime and sub-equatorial regime. The main geological formations of the basin are granites, migmatites and granodiorites. There are two types of aquifers that are the regolith aquifers and fissured aquifers. The methodological approach is based on the evaluation of recession coefficients, of the dry period and the water volume mobilized by the aquifers. All these parameters were estimated from the law of Maillet. The recession coefficients estimated average between 3.14.10-2j-1 and 3.56.10-2 j-1 either side 1968, whether an average increase of 15.26% and highlight a drain much faster aquifers supplying base flow after 1968. Shortening of 1 to 9 days with an average of 5 days of drying time after 1968 was highlighted. The water volume mobilized by the average aquifer fluctuates between 0.84 and 0.42 Km3 before and after 1968 whether an average decrease of -49.3%. These results show a decrease in the water volume mobilized by aquifers after 1968 and suggest a considerable decline of groundwater resources under the influence of climate change. Keywords: Climate change; Water resources; Maillet law; N’zi-Bandama; Ivory Coast. INTRODUCTION