Investigation of the\xa0diapirism\xa0effect on increasing salinity and solubility of water resources: a case study in eastern Tehran Province

Abstract

The water potential in east of Tehran plain is different due to a variety of evaporative formations and the effects of fault structures and diapirism. In this study, the relationship between features of water sources, especially salinity with geologic settings and a structural property, is investigated. A field investigation was performed after determining the study range in the Eyvanekey area to identify the geological formations and distribution there along with the faults and salt domes locations using geological maps. Afterwards, by identifying the wells’ location and by using the decomposition results of water samples of the area, the concentration contour maps of chloride, sulphate, and sodium, among others, were plotted. The faults’ performance and the plotted maps’ interpretation showed that the highest salinity concentration lied in the eastern and southern parts of the plain; their change trend occurred in highlands towards central and western parts of the study range, which is consistent with the main river path. Considering the qualitative results of the water, the eastern and southern parts of the plain are typically of sodium chloride nature, while the water of the area is classified as non-potable in terms of potation and harmful saline with regard to agricultural use. The study findings showed that the high evaporative mass erosion rate, and gypsum and saline sediment transport have developed saline fields in the plain. On the other hand, disorganized exploitation of water sources has considerably reduced the water quality and increased the salinity in the area.