Abstarct: Forumad Plains with an area about 650 square kilometer, is located 180 km east of Shahrood. The climate of this area is arid and the average annual precipitation is about 150 mm. A significant percentage of drinking water and irrigation in the plain provided from Qanatʼs which indicates the importance of protecting these water resources. According to equipotential map, the general trend of groudwater flow in this plain is from the northeastern toward southwest, which is consistent with surface currents. Moreover, it can be seen that the hydraulic gradient in the upstream of the plain is relatively high (i.e. about 0.08) and it markedly decreases in the downstream of the plain (i.e. about 0.016). The main reason for decreasing the hydraulic conductivity in the downstream of the plain is discharging the groundwater by qanats and consequently decrease in groundwater discharge in the aquifer. In general, the groundwater level in this plain has been declining and has fallen by 0.42 meters over a period of 5 years, with an annual average of 8 centimeters. The reason for this relatively low drawdown is that the main drainage of the plain is carried out by the qanats. According to the obtained results, Hardoab qanat with average discharge about 22.8 l/s has the highest discharge whereas the qanats of Mohammad Abad and Hossein Abad with average discharge approximately 3.8 l/s have the lowest discharg. In addition, the coefficient of variation of discharge for Stakhr Sefid qanat is highest (i.e. 10.6%) while it is for Kheir Abad-Shahrestan is lowest (i.e. 1.7%). The hydrogeochemical studies showed that the lowest electrical conductivity of groundwater in this plain was 417 µmhos/cm, which is related to the Eish Abad well and the highest value of electrical conductivity is 1480 µmhos/cm, which is related to the Stakh Sefid qanat. By calculating ionic ratios and plotting qualitative charts, dissolution and ion exchange were the dominant processes in determining the chemistry of the region and the dominant type of water is Cl-Na and HCO3-Na.