Abstarct: The Davarzan alluvial aquifer, with an area of 703 km2, is located in the west of Khorasan Razavi Province, Iran. It is bounded by the ophiolitic complex to the north and the salt playa to the south. Continuous groundwater abstraction over the years has led to water table decline and reduction of available and exploitable water storage in the region. baxsed on the quantitative studies conducted in the Davarzan aquifer, the groundwater flow direction is from the north and northeast (the ophiolitic heights) to the south and southwest (the salt playa). The water table decline in the Davarzan aquifer varies from a minimum of 6.1 to a maximum of 10 meters over a 17-year period. The representative hydrograph of the Davarzan aquifer shows an average decline of 36.0 meters for the whole aquifer over a 10-year period. The hydrochemical studies of the Davarzan aquifer indicate that the electrical conductivity ranges from 430 μS/cm in the northern parts to 4400 μS/cm in the southern and western parts of the plain. The increase in salinity in the southern part can be attributed to the concentration of abstraction wells near the salt playa in the southern part of the plain. Considering the lack of a significant increase in salinity in the plain, it is likely that fresh water has been flowing towards the saline water, causing a freshening phenomenon. The water type in the fresh samples is sodium bicarbonate and in the saline waters is sodium chloride. All water samples in the area are supersaturated with respect to calcite and dolomite and undersaturated with respect to gypsum and halite minerals. The heavy mextals assessment in the Davarzan aquifer shows that the main heavy mextal contaminants in groundwater are chromium, iron, arsenic, and lead. Although the ophiolitic complex in the north of the aquifer has the highest potential for chromium, the lowest chromium concentration in groundwater was measured near the ophiolitic zone, which is in the range of its discharge springs. According to the conceptual model of groundwater contamination, the geochemistry of the ophiolitic complex, the soil composition of the unsaturated zone, and the flow direction control the chemical composition of groundwater. Chromium samples have a direct relationship with the EC value, which indicates that the infiltration of salinity from the salt playa is probably another reason for the increase in chromium concentration. The results of the health risk assessment showed that groundwater is significantly contaminated and, if used for a long time without treatment, may pose risks to human health through drinking water. baxsed on the groundwater modeling, the safe yield using the Hilla method was estimated to be 64.3 million cubic meters per year. This withdrawal is equivalent to 18.3% of the current average withdrawal and is considered as the maximum safe yield in the aquifer. The baxse period for estimating sustainable yield in the Davarzan aquifer was considered 41 years (1400-1440). The results showed that assuming that the withdrawal continues at the current constant rate in the coming years, the storage changes after 28 years in 1427 will reach zero due to the increase in the slope of the groundwater inflow and the decrease in the groundwater outflow. If the groundwater inflow does not have the potential to increase and reach the specified volume in the target year, the current withdrawal will lead to the depletion and complete destruction of the aquifer. Therefore, to reach a sustainable condition (storage change equal to zero), the withdrawal rate should be reduced by at least 18%. This amount is equivalent to 63.41 million cubic meters per year. baxsed on the calculations, the total storage of the Davarzan aquifer was estimated to be 2.8 billion cubic meters, the renewable storage about 49 million cubic meters per year, and the static storage about 2.751 billion cubic meters. Therefore, the continuation of the current trend of groundwater withdrawal, which causes a decrease of about 13 million cubic meters per year from its storage, will lead to a continuous decline in the groundwater level and consequently the complete depletion of the aquifer within a maximum of 211 years. The mentioned number is obtained by assuming that the wells are drilled up to the bottom rock of the aquifer and that other hydrological components such as recharge remain constant.