QUANTITATIVE AND QUALITATIVE SIMULATION OF GROUNDWATER BY MATHEMATICAL MODELS IN AN ARID REGION USING MODFLOW & MT3DMS

Agriculture sector by using 80 percent of fresh water is the greatest water consumer in Iran. Excessive use of agricultural fertilizers in last decade, caused accumulation of enormous amounts of salts and subsequence declined the physical properties of soil. In desert and dry regions such as Rafsanjan plain, use of the groundwater resources is more than the surface water resources. Therefore, information about the quality of these resources remains a necessary task for optimum management, protection of water resources and stopping the future damages. In this study the groundwater quantity and quality of Rafsanjan plain was investigated by MODFLOW and MT3DMS. The presented qualitative model for this aquifer was compared by observed data and calibrated. Then sensitivity analysis was; preformed and this model was used to predict the next 2 and 5 years. Results show that water level decrease in coming years dramatically and most quantity parameters will increases in plain, too. Electrical conductivity will increase more than other parameters. Therefore, discharge should be decrease and recharge increase in this plain.