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.

Measurement of irrigation water in agricultural areas is necessary, especially, in arid and semi-arid regions. Long-throated flumes have been used to measure irrigation water and are known to be inexpensive devices with high performances. In these structures, head-discharge tables are predicted theoretically with no need to calibrate. In this study, the model of LOTF (LOng Throated Flumes) was developed in VB. net programming language, in which, friction head loss and h-Q (h is head at measuring station and Q is discharge) tables were predicted by using the Manning's equation. The predicted tables of h-Q by the LOTF model were perfectly similar to the results of Win Flume and HEC-RAS model which are universally used for these flumes and open channel flow, respectively. Calculated h-Q tables in trapezoidal flumes with two different side slopes of 0 and 1, 0 and 2, and 0 and 4 were computed by the LOTF and HEC-RAS models and were the same as those predicted by the WinFlume model with equal average of these side slopes of channel. At a water depth, in trapezoidal sections with different and equal average side slopes, the resulted h-Q tables in the three models were the same.

Accurate water measurement is one of the key factors for reduction of agricultural water consumption, distribution integrity and delivery management in irrigation networks. In recent years, there has been a significant advance in flow measurement devices, but the usage of these devices is limited due to the high cost, special maintenance conditions and the need for skill expertise. Water structure used in this study is a new form of flow measurement flume that installed along the channel and has cylindrical and conical shape walls. The crest matches the channel's floor thus in this measuring structure, the control section happens only by transversal constriction. The new flumes are simple in shape and easily applicable in irrigation networks and they have not sedimentation problem. The amount of energy loss and consequently the upstream backwater in this structure is low. This structure controls the flow by creating critical flow in constriction section and will be able to measure flow discharge. In this study, the flow characteristics through the cylindrical and conical flumes have been studied theoretically and experimentally, and several equations have been developed for flow discharge estimation in rectangular open channels.

In order to use gated pipes efficiently, it is required to know the hydraulic properties of the gated pipe and its gates. The hydraulic properties of gated pipe's gates were studied. The manufacturing quality and the discharge similarity of gates were evaluated by computing values of indices including Cv, qvar and Range. Results indicate that the manufacturing quality of gates is acceptable and their hydraulic performance's is similar.Therefore, an equation was developed to relate gate discharge to the hydraulic head behind the gate and the gate degree of opening. The gate discharge was computed under various conditions of pressure head and degree of opening with the equation derived and compared with measured values. The computed values of gate discharge were close enough to the actual values for practical purposes. A computer program was developed to simulate gate discharges along a gated pipe. The program calculates gate discharge and pressure behind the gates along a gated pipe line based on known values of pipe slope, length of pipe, gate degree or opening, gate spacing, pipe inlet pressure or discharge of last gate on the pipe line, distance from the pipe inlet to the first open gate, and numbers of open and closed gates at the beginning of the pipe.

This paper describes the design, construction, and testing of a small wave flume and associated equipment. The wave flume is equipped with a flap-type wave generator, capable of producing both regular and irregular waves. Flap paddle is used to examine deep water and floating structures. Instrumentation includes three capacitive wave gauges. The wave-maker is controlled by a desktop computer, which also provides data-logging capability. In order to design a wave absorber of restricted length, all the different mechanisms able to dissipate wave energy studied. Finally from the survey of the wave absorbers used in different laboratories, a gravel beach designed for absorbing the waves coming from wave maker. By sealing leaks around paddle the error of measuring height-to-stroke ratios versus relative depth is decreased by 3%. The main advantage of this system over the previous ones is reduction of the amount of effort in the set up with optimum deflection and low level cost utility.