Mohammad Valipour - Department of Irrigation and Drainage Engineering, College of Abureyhan, University of Tehran, Pakdasht, Tehran,

One of the most important factors for appropriate performance of subsurface drainage systems is having adequate inflow to the drain for improvement of soil environmental conditions. For this purpose, knowledge about effect of drainage parameters change on drain discharge is essential in subsurface drainage systems. In this article, using change all of the drainage parameters by EnDrain software, changes of drains discharge has been investigated in subsurface drainage systems. The most amount of change in drain discharge for one percent increase or decrease in each of drainage parameters was owned by depth of water level in drain below soil surface equal to 3.0%. Also about maximum and minimum of obtained drain discharge for drainage parameters change has been discussed.

drain discharge, improvement of soil environmental conditions, subsurface drainage systems design, watertable control