An Assessment of a Long-Throated Flume with a Broad-Crested Weir Cross-Section for Flow Measurement

Water-use-efficiency، which is a matter of utmost importance in irrigated-agriculture in the water-short Iran، requires installation of accurate flow measurement devices on the outlets of delivery channels. Accuracy، low cost، and ease of installation and measurement are the criteria for a good measuring device. As a long-throated flume with a broad-crested weir cross-section had been studied in detail by Zand-Parsa، and the Win Flume software was available for the design of the flume and processing of the collected data، 10 such flumes were installed in 3، third degree channels in the Dorudzan Irrigation District in 2007; however، this study was implemented in the 2012 irrigation season، using 3-5 replication for each flume set up. Both our collected data and the Win Flume program validated the equation developed by Zand -Parsa. It was observed that the percentage error in measuring low flows ranged 12-21، which was much higher than that of the maximum flow? Based on these results، the large scale use of this device and the application of the Zand-Parsa equation are recommended