Abstarct: The Sabzevar alluvial aquifer, covering an area of 2153 km² with a general east-west trend, is located in the eastern part of the Central Kavir watershed and is an unconfined aquifer. The general direction of groundwater flow is from the east to the west, which aligns with the topographic slope and surface water flows. Recharge of this aquifer occurs primarily from the limestone highlands in the northern parts of the plain. The Attaieh plain to the east of the aquifer may act as a source of subsurface inflow. Regarding surface flows, the Kal-e Shur is a seasonal river that enters the Sabzevar plain from the east after passing through the Neyshabur and Attaieh plains, and discharges into the adjacent salt playa from the west. The range of electrical conductivity (EC) in the water resources across the plain varies from 627 µS/cm in the northern recharge area of the aquifer to 11,600 µS/cm in the central part. Electrical conductivity increases from the northern and southern parts towards the center of the aquifer due to the flow of the Kal-e Shur River in the central section, as well as the influx of saline groundwater from the Attaieh plain. Increased groundwater extraction and the consequent decline in the water table in various parts of the plain, particularly in the southwestern section, have caused a reversal of flow gradients towards the wells. This has resulted in the formation of closed potentiometric contours in this area, creating a well field. The depth to water table varies from 4.48 meters in the central part of the aquifer to over 100 meters in the northern parts. Over a 19-year period, water level drawdown in the Sabzevar plain have ranged from 0.3 to approximately 15 meters, with an average decline rate of about 0.7 m/year. The highest declines have occurred in the recharge areas of the eastern and northern parts of the plain, which could be attributed to a higher concentration of wells and greater abstraction in areas with thinner alluvial deposits. baxsed on data from the Water Table Fluctuation (WTF) method, the average annual recharge of the Sabzevar aquifer was estimated to be approximately 40 MCM. Water balance calculations estimated the aquifer recharge of 44.3 MCM. According to the unite hydrograph, the overall trend of groundwater level changes in the studied plain is declining. This aquifer exhibits an average annual storage deficit of 33 MCM.