The impact of halite dissolution of salt diapirs on surface and ground water under climate change, South-Central Iran

Abstract

The climate change may affect the hydrological behavior and water quality of surface and ground waters across the world. The problem becomes very important in regions that the water quality is deteriorated by the evaporitic formations. One of these regions is South-Central Iran where numerous salt diapirs deteriorate the quality of water resources. The study area includes Konarsiah, Jahani and Khurab salt diapirs, where these diapirs currently deteriorate the quality of the Firuzabad River water. Part of the water of the Konarsiah salt diapir is discharged from eight brine springs, and a small part of it flows into an adjacent karst aquifer, emerging as the saline Konarsiah spring. The objectives of this study are to determine the changes of salt diapir dissolution and salinity of the water resources under the climate change. Daily precipitation generated by the Canadian global coupled model is transiently downscaled at the Firuzabad meteorological station using LARS-WG. The precipitation will decrease by 13, 19 and 28 %, under scenarios B1, A2 and A1B, respectively, for a period of 2015–2095. Consequently, the average annual discharge of the Konarsiah salt diapir springs, Konarsiah spring and Firuzabad River will also decrease. The annual mass of dissolved halite in the water resources under the influence of the three salt diapirs will decrease, but the annual salinity of these resources will increase under climate change. The percentage increase of salinity in the Konarsiah spring is lower than the Firuzabad River due to the different hydrogeological behavior of these two water resources. Most of the aquifers in South-Central Iran are overexploited; therefore, the salinity increase may intensify the present water crisis. It is recommended that salinity increase due to climate change be taken into account in any future water management for areas having evaporitic formations and precipitation reduction.