Evaluation of seepage losses in irrigation stone-lined canals in cold regions and its effect on water resources (Case study in Hamedan province)

Lining of irrigation canals with suitable materials is imperative for sustainable agriculture in water scarce areas. Durability and seepage losses of different linings are related to three technical characteristics i.e. external factors, meteorological conditions and kind of flow. Therefore, it is necessary that in different areas, all various linings be evaluated and suitable lining chosen for decrease seepage loss and optimum usage from water resource. Total length of lined irrigation canals in Hamadan province of Iran is 800 km. More than 60% of them are concrete-lined canals and the rest have stone linings. The aim of this research was to determine water seepage loss in the main stone-lined canals irrigation network that serves the irrigated area on Hamadan plain. Six main canals with total length of 15.25 km were chosen to study in this area. Water seepage in these canals was measured by the inflow-outflow method. While water velocity was determined using a current-meter. The water seepage loss at canals was between 0.24 and 0.65 m3m-2day-1. The average seepage loss was 0.34 m3m-2day-1. It was noted that the average seepage loss of the chosen canals was much smaller than the value of water seepage loss for open concrete-lined canals in this area (20%). With reviewing or replacing of this lining instead of the concrete lining, the loss of water can be reduced and planning for optimal use yearly more than 6.4 M.C.M. in the entire province, equivalent to 20% of Ekbatan dam volume. It’s because of durability and longer-lasting of stony lining in such cold climate conditions.