Investigation of groundwater quantitative change, Tehran Province, Iran

Changes in groundwater level in Homand-Absard plain, located in north-west of Kavir-e-Markazi watershed and east of Tehran province, were studied. The used research method was descriptive approach, and the research study was conducted based on field and desk surveys. The data needed was provided from field surveys, contours maps, and data of observation wells. There were 17 observation wells in the study area where the changes in groundwater levels were measured during 1996-2013, and an index hydrograph was prepared for the aquifer of plain. The sharpest decline in the groundwater level was in the central of Homan-Absard plain. There was 1.43 m decline in the groundwater level of aquifer annually, compared with similar studies in other parts of Iran, it has a high rate, and to the average, the groundwater level of plain has dropped equal to 25.76 m, 1996-2013. According to the study findings, the groundwater level changes with those in rainfall weren’t match and the drop in groundwater level during wet years and then has continued which represents the high water extraction factor on the groundwater level drop.