Investigation of Qazvin Marshland Interceptor Drain Effects on Water Table Using Seep/w Model

The groundwater level dropping has many problems. One of the most important problems is saline groundwater advancing in the upper area of the plains. Also, decreasing of saline effluent from the groundwater is another problem that occurs. The interceptor drain is a method for solving these problems. In this study, effect of Qazvin marshland interceptor drain is simulated. To monitor the effectiveness of these drains, wells of 99 loops were excavated in 9 sections perpendicular to the drain (A to I). Seven wells per section were excavated in the upstream at 10, 25, 50, 100, 250, 500 and 1000 meters distances from the drain and 4 wells in the downstream at 10, 25, 50 and 250 m. The wells water level was measured in once a month and a water sample was taken from each. Chemical analysis of the samples, and chemical changes in ground water drainage were determined. The condition of affected by drainage was simulated using the software package Geostudio. Model, the hydraulic conditions (model Seep/ w) is the model. The numerical model used in section B was calibrated using observations of August 2010 and the data were collected four months after it was verified. In the calibration phase, Values of modeling efficiency and coefficient of determination were 0.91 and 0.97, respectively. These values were 0.87 and 0.91 in validation phase, respectively. These values of validation show the good efficiency of the model in groundwater level prediction.