STUDY OF THE IMPACT OF THE RUS FORMATION ON THE NATURE OF THE GROUND WATER IN THE AREA BETWEEN SAMAWA SALT PAN TO

Abstract

Thy study area is located within Al-Muthana Governorate within Southern Desert, in southwestern of Iraq. It is bounded between latitudes (30.597 – 31.337) Northing and longitudes (44.96 – 45.03) Easting. The exposed rocks in study area are represented by: Dammam, Euphrates, Ghar, and Nfayil formations, in addition to the Quaternary sediments. From the structural point of view the area is located within the Southern Desert of Iraq, which belongs to the Stable Shelf of the Arabian Platform. Topographically the map area is characterized by flat rocky terrain associated with structural ridges and karst landforms. The climate of the map area is under the conditions of arid climate, which is highly affected by desert condition. It is characterized by hot and dry summer and relatively cold winter with low rain fall. The study area results are based on using the Geographic Information System software, which determines the physical hydrology properties and calculates the basins watershed and the area 1891 km2, stream slope gradient (1-2) m/Km. The stream flow direction is toward the northeast, and the main stream order is the ninth order. Dammam Formations represent the main aquifer within the area. Rus and Umm Er Radhuma formations represent the deep (second) aquifer. The groundwater flows northeast towards the Abu Jir Fault and the Euphrates Boundary Fault. This study was based on drilling results of 12 wells, ranging from depth between (94 – 150) m. Depending on the drilling operations in the region have been mapping the contour depths Rus Formation in the area, it was noted that this formation varies in depth between (70 – 110) m, where getting deeper as we head north towards the Mesopotamia Plain. It was noted that the extension of the Rus Formation in the area of Abu-Jir Faults Zone contain hydrogen sulphide gas H2S which, by itself, is a pollutant gas of both water and environment. Also, it can be seen that the Rus Formation varies laterally in thickness and lithology; it is 84 m thick in west of Samawa City, made up essentially of evaporite with occasional limestone layers. At Salhaubiya, it becomes mainly evaporates with a reduced thickness of 60 m, at Shawiya, the Rus Formation becomes thicker (about 110 m) consisting of upper evaporatic part, some 50 m thick and a lower calcareous part; 60 m thick. At the neighboring Salman City, the Rus Formation becomes 48 m thick with the total disappearance of the evaporatic layers.