Quality of Hamadian groundwater table of the continental tertiary of Wadi Mehiya in Tindouf province (South-West of Algeria)

Abstract

AbstractThe Hamadian groundwater table ensures water supply for the agricultural perimeter of Wadi Mehiya region in the North-East of Tindouf city. In order to determine the behaviour of this groundwater table, a piezometric map have been realized, followed by physicochemical analyses to assess the chemical facies, the suitability of this water for irrigation and drinking purposes, as well as its vulnerability to different pollutants. This groundwater table is essentially composed of fine to coarse and clayey sands, surmounted by a silicified limestone slab. It is a free groundwater table with a thickness of 18 to 99 m. The sampling has been done in June 2010. Then, the physicochemical analyses have been performed on 7 samples taken from 7 boreholes. The piezometric study proved that the flow of groundwater table follows a North-East to South-West direction, towards the Sebkha of Tindouf. The graphic representation of chemical facies, using Piper and Schoeller–Berkaloff diagrams, reveals that the water of Wadi Mehiya contains mainly magnesium sulphate. The graphical representation of irrigation water quality, using Wilcox diagram, revealed an acceptable quality with a high salinity. Moreover, this water is potable with hard-mineralized character. Nitrates contamination has been also noted, which is a logical result of the excessive use of chemical fertilizers.