Investigation Phreatic Line Slope in Irrigation Channels Embankment of Mianab Irrigation and Drainage Network Using SEEP/W Model

One of the problems of existing irrigation networks is seepage phenomena. Seepage problem and its control in irrigation channels is one of the most important issues in the design, construction, maintenance and operation of these channels. In this study, simulated the rate of seepage and phreatic lines in the Mianab irrigation and drainage channels located in the Karun basin using mathematical two dimensional SEEP/W model. Results show that when flow depth in main channel be equal or more than 1.69 meters, the phreatic line intersects the downstream walls of embankment and exist the probability of piping phenomena. By increasing flow depth in main channels, increase phreatic line slop. Hydraulic conductivity coefficient don’t influence on phreatic line and only water surface elevation in main channel influence on phreatic line.