Assessment of the Effect of Fractures on the Occurrence of Springs in Sardashat and Shayoun Area in

The Sardasht and Shayoun area in the north of Dezful embayment structure and on the southwest of Zagros structural belt is affected by shear zone pattern of Balarud. This watershed occupies an area of about 1042 km2 and encompasses parts of Dez, Shirinab and Sardashat watersheds. The purpose of this investigation is the assessment of structural factors (specifically fractures) on sandstone permeability and spring occurrence in the study area. In this investigation, geology and structural geology including folding, faulting and fracture studies were carried out. For fracture examination, joint data collections from eleven stations were analyzed and the collected data taken into account to prepare the structural map of the area. The iso-density fracture map indicates more permeable zones. It is also evident from the map that springs are mostly occurring in dense fracture zones of the area. The position of the springs, their structural and qualitative characteristics were assessed, and found that springs with more discharge, showed more temperature fluctuation in wet and dry seasons.