Karst development potential and karst conceptual model of Abivard dam site using structural geology and geotechnical studies and Analytical Hierarchy Process (AHP) method

Nowdays, many dams are building in karstic areas, and usually due to the complex hydrogeology of karst areas, the sealing of these dams are more difficult, longer and expensive than other dams, and the possibility of water leakage from them is higher. Therefore, it is necessary to investigate the role of karst development in the dams’ sites. The Abivard dam is an earthen type with a clay core, with a height of 51 m and a lake volume of 43 MCM, near Ilanjogh village. The emergence of downstream springs in calcareousness Kalat formation, after temporary dewatering of Abivard dam, the development of karst due to the outflow of water is considered as the most important problem of the dam. In this article, the development of karst in the area and dam site were investigated by carrying out the geological, structural geology, geotechnical permeability and analysis hierarchy process (AHP) studies. The results show that about 2.4 % of the the Abivard dam area (680 km2) has a high potential of karst development and there is water leakage and water escape from the Kalat formation on the right hand side and in under the dam, but still karst is not well developed. According to the prepared structural-conceptual model for the dam and the location of the dam reservoir relative to the Kalat formation layering slope, which is parallel to the sothern limb of Abivard syncline, there is a possibility of karst development in the dam site.