Deferent theories that have used in saltwater intrusion studies have reviewed in this thesis. And the properties of Kashan plain as case study region have introduced. Transmisivity of case study aquifer have estimated by R.T. map and pumpage tests results. Groundwater flow and its quality modeled by VISUAL MODFLOW model. We study the variation of chloride for control of groundwater quality. 38 year (1964-2002) have been selected for accuracy test of model. Flow model by 1.4 meter and quality model by 52 milligram per litter mean absolute of errors are reasonable and acceptable. Then we predict the aquifer water table and chloride concentration by this model under different scenarios in year 2020.By running of model under present conditions, the maximum of drawdown in 56 year of model run is 78 meter. There is a pipeline that is traort the water from Zayanderood river to Kashan. model indicate that the backwater of Zayanderood water decries drawdown in center of plain to year 2020. Model indicate that the chloride of region groundwater at year 2020 under two above alternatives is very similar and in two alternatives discharge wells that are near the saltwater region will have maximum impact on aquifer chloride change. Next we study the hydraulic gradient of aquifer in cross section perpendicular the saltwater region. Cross section indicates that the hydraulic gradient has been inversed near the saltwater region. By terminate discharge of wells near this region, model indicate that the hydraulic gradient again will be inverse. By moving the discharge of these pumpage cells to upstream of plain also model indicate that the hydraulic gradient will change to downstream of plain to 2020.
