Document Type : Research Paper
Ph.D. of Water Engineering, river engineering expert in Mazandaran Regional Water Company,
Water Resources Management Group, Wageningen University, Wageningen 6700–6709, The Netherlands
The results of calculating the flow components showed that when the water table was at a higher level, the total load was overestimated, and conversely, when the water table was at a greater depth, the total load was underestimated. This condition is due to the discharge from the drains, that when the water table is close to the ground, the most of the water reaches the drainage trench and pipe by moving horizontally from above the harden layer and has a high discharge. However, with the drop of the water table, the discharge enters the drain from the harden layer or below it, mainly by radial movement, and less discharge comes out of the drain. Due to the presence of different layers in the soil and a layer with low hydraulic conductivity below the surface layer, the measured values of the flow components were very different from the calculated values.