Quantitative and qualitative hydrogeological study of groundwater resources in fractured rocks aquifers (Case study: Almaneh Basin, Marivan)

Sandstone and Igneous units have formed fractured rocks aquifers in Almaneh basin at south-west of Marivan city at the western Iran. The aim of this research is to evaluate ground water from quality and quantity views of points. Fractured rock and alluvial deposition has occupied 80.2% and 19.8% of the study area, respectively. After determination of fractured aquifers, relationship between fracture density and streams pattern were investigated. About 76% of total discharge of the springs is draining from fractured rocks and the highest value of mean discharge belongs to gabbro and diorite rocks and the lower value is for alluvial aquifers (with a value of 0.5 and 0.8 L/S, respectively). Specific discharge of the ultrabasic rocks estimated as 2.28 L/SKm2 as the richest aquifer of the area and gabbro to dioritic rocks with 0.86 L/SKm2 value is the poor units from water resources viewpoint. In the northeast and southwest parts of the area, the fracture density is high that coincide with the location of the springs showing the role of tectonics at aquifers recharge. In order to evaluate the hydrochemical characteristics of groundwater some samples were collected and analyzed. It revealed that the type of waters is chloride and sodium -magnesium with an ascending trend of EC, Na and Cl concentration from east to west. GQI index values varies from 90 to 92 means that the water quality is located at the excellent range confirming the results of Scholler diagram.