The role of Khoshkarud fault on hydrogeological behavior of Zarandieh Saveh aquifer

Correct exploitation of groundwater water resources in any area requires knowledge of geological and hydrological features and structures of that area. Tectonic structures, especially faults, have a major impact on the abundance and quality of groundwater resources. The purpose of this research is to investigate the effect of Khoshkarud fault on the hydrogeological characteristics of the aquifer of Zarandieh Saveh plain. This aquifer is located in the north of Markazi Province. In this research, the changes in the hydrogeological parameters of the aquifer on the sides of the fault line were investigated using the data of the 21-year statistical period (1990 to 2011) and using ArcGIS 9.3 software.The results showed that the highest thickness of alluvium and the maximum transverse electrical resistance equal to 6000 ohm-m2, in the center of the northern block, and lowest thickness of alluvium and the lowest value of transverse electrical resistance It is equal to 500 ohm-m2, located on the southern block, which indicates the direct effect of the fault on the aquifer geometry. In the western region of the Khoshkarud fault and from the beginning of the fault's entrance to the aquifer to the vicinity of Shokhroud city, 23 km long, due to the absence of transverse flow from the fault and the flow direction being parallel to the fault line, the dissimilarity of the water level drop trend in the piezometers opposite and on the sides of the fault in the 48-month time series (2008 to 2011) and the dissimilarity of the distribution map of the concentration of hydrochemical parameters sampled in September 2011 on the sides of the fault, shows that in the western part of the aquifer, the fault acts as a hydraulic barrier, While in other parts of the fault extension, there is a connection.