Emplacement of Underground dam Sites in Gaz River Basin in Hormozgan province Using GIS

Abstract Management of underground resources has a special priority in arid and semi-arid in Iran. Increasing underground resources is one of the useful ways for providing water requirements during the drought years, The main objective of this study was for mapping underground dam in the basin of Gaz River in Hormozgan Province was selected. Accordingly, using regional analyzes and analyzes, digital elevation models, satellite information, hydrological characteristics, geology and meteorology were investigated in appropriate software, especially GIS, in remote sensing, and eventually Three sites were suggested. After preliminary examinations and field visits from selected sites, site number 2 was selected as the prime and priority site. The site is geologically located on sandstone and conglomerate units, and a small Chilean sand gravel with good permeability. Quaternary sediments including alluvium and alluvial terraces are also seen at the margin of the flood zone of Gaz river with acceptable permeability. The surface slope of the river was estimated at 2.5%, which is topographically prone to underground dam construction. The reservoir drainage area of the proposed site is estimated to be 777600 cubic meters per day and the reservoir will be filled in for about 69 days. Therefore, with proper management, it is possible to drain 3-4 times per year. Thus, the annual drainage capacity of the dam is estimated at 3,110,400 cubic meters in four turns.