Factors Governing the Impact of Emerged Salt Diapirs on Water Resources

Salt diapirs in southern Iran are typically in contact with karstic and alluvial aquifers and consequently they are the most likely sources of groundwater salinization in this arid region. However, there are some salt diapirs that have no significant degradation effect on adjacent aquifers. Assessments of 62 of 122 Iranian-emerged salt diapirs based on geological, geomorphological, hydrogeological, and hydrochemical investigations indicated that 45% of the studied salt diapirs did not have a negative impact on surrounding water resources, whereas 55% of the salt diapirs have degraded water quality of adjacent aquifers. The impacts ranged from low- to high-grade salinization. We characterize here four major factors that control the impact of salt diapirs on surrounding water resources: (1) the evolutionary stage of the diapir, (2) the geological and (3) hydrogeological setting of the diapir, and (4) human activities. Identification of the major factors governing the influence of salt diapirs on the adjacent aquifers is necessary to understand the mechanism of salt diapir impact on adjacent aquifers, and subsequently to decide how to mitigate the deteriorating effect of the diapirs on the surrounding water resources.