Evaluation of conveyance efficiency and water seepage loss in irrigation canals with HDPE geomembrane lining in plains of Zaiandeh-rood, Moghan and Kerman

In this study, the amount of water losses in 7 irrigation canals in plains of Zaiandeh-rood, Moghan and Kerman, with the same specifications of HDPE geomembrane lining with the same age, were evaluated. For this purpose, the losses of water in the canals was determined by input-output method in three stages. At the same time, the amount of evaporation using a class A pan installed in next canals, was determined. to calculate seepage losses, the amount of evaporation losses were deducted from the total losses. Based on results, the amount of efficiency efficiency was between 95.9 to 99.7 and in averagewas 98.9 percent. The total losses in the canals was determined between 3.3 to 13.8 and averagely 11.5 lit/s per kilometer. From total losses, between 3.3 (Zaiandeh-rood) to 16.2 (Kerman) and in average 7.1 percent was due to evaporation and the remainder was due to seepage losses from geomembrane lining. The seepage losses in evaluated canals was between 0.03 (KC in Kerman plain) 0.16 (EC4 in Zaiandeh-rood ) and an average of 0.1 m3/m2/day (17 times lower than the concrete lining). The results of this study showed remarkable impact of geomembrane lining in control of water losses from irrigation canals and its advantages compared to conventional concrete lining.