The Trend of Changes in Groundwater Quantity and Quality in the Sarvestan Plain of Fars Province

Dependence of agriculture on groundwater in the Sarvestan Plain has necessitated the implementation of appropriate policies for sustainable utilization of this resource. An assessment of the quantity and quality of groundwater in the plain, and evaluating the effect of overdraft on them, is of paramount importance. The purpose of this research was to investigate the long-term impact of groundwater overdraft in the Sarvestan Plain on its quantity and quality. Water-level and salinity data collected from 24 observation wells from 1991 to 2016, and from 24 operational wells from 1998 to 2015 were analyzed. Results indicated that water-level in the long-term has dropped 47 cm/yr, which is slightly faster than the water-level trend in the last five years (39 cm/yr) indicating a lower rate of water-level drop in the recent years. Forecasting water-level in 2030, based on the last five years' trend, indicated that the drop in water-level will be very high in areas such as Kohenjan, Dehnow and north of the city of Sarvestan, reaching a depth of more than 80 meters. Results also indicated that the salinity has increased by an average rate of 100 microsiemens per centimeter per year. Furthermore, the average water-level and salinity trends in the plain indicated that water salinity has increased with an increase in depth to groundwater; however, this has not been the case everywhere in the plain.