Investigating the Conveyance Efficiency and Providing a Solution to Reduce Water Losses in the Canals of the Left Bank Irrigation Network of Ramshir City

Considering that Iran is a country where most of its locations have arid and semi-arid climates and with a scarcity of water preventing losses of this national resource is extremely important. One of the ways to prevent losses is to implement basic and scientific irrigation networks and increase the efficiency of water transfer. Therefore, it is necessary to evaluate the work done on irrigation networks and determine them as weak and strong. In this study, to estimate the water transfer efficiency of irrigation and drainage network of Ramshir left coast, 5path channels type canalet of B-block were selected as samples. Among the canals studied, some of them had water overflow problems in the body due to sedimentation in the bed and others didn't have this problem. The amount of discharge for each section was calculated according to the operating conditions in winter and negligible evaporation and by obtaining the difference in discharge in the entrance and output of each section from the sample channels, the water transfer efficiency was determined. The results of this study showed that the water transfer efficiency in the canals without overflow problems was between 88.40% and 89.18% and in the channels with water overflow problems from the body was between 63.66% and 71.52%. The reason for the reduction of water transfer efficiency in the channels with  overflow problems is due to the sedimentity of the water supply (Jarrahi River), their inappropriate slope and its consequences is the reduction of the power of sediments transport in the canal bed by the flow of water.Therefore, the effect of decreasing the flow transfer capacity due to the change in roughness coefficient due to sedimentation in the canal bed and also occupying part of the flow channel by sediment and water flow in parts of the body of these canals has reduced the water transfer efficiency and increased the losses. In order to improve this condition and improve the water transfer efficiency in the mentioned network, It was suggested that sediments with diameters greater than 1 mm in water supply and before transferring to canals by trapping sediment pond and sedimentary particles up to 1 mm that enter the studied canals should be transferred using the change slope of the current status of the canal and prevent sedimentation in their bed