## 2 Flow Gauging Test of the Integrated Measurement and Control Gate  
The irrigation flow gauging test is limited by many factors. For example: the flow gauging test directly affects farmland irrigation; irrigation gates cannot be arbitrarily raised and lowered; the upstream water flow cannot be freely controlled; the water flow pattern needs some time to stabilize after the gate opening change; flow measurement equipment is greatly affected by environmental factors and large measurement errors can lead to low accuracy of the flow calculation model; and there is a lack of a professional testing institution and testing platform for the integrated measurement and control gates. Due to the above reasons, there are few reports of indoor flow gauging tests, and most scholars mainly use numerical simulation to conduct flow gauging tests [15; 16]. The numerical simulation results need to be verified with actual measurement data, so there is an urgent need to conduct indoor flow gauging tests to provide data support for subsequent research.  
The flow gauging test in this study was conducted at the measurement and control integrated gate testing center of Ningxia Tianxianglin Water Conservancy Measurement Facility Inspection Co., Ltd. This testing center is the only professional testing institution for integrated measurement and control gates in China. The experimental platform consists of three parts: a water supply system, a flow measurement section, and a return water system. The water supply system consists of three sets of water pumps, with a discharge range of 100-2600 m\({}^{3}\)/h. Discharge can be controlled by the frequency conversion system, and the flow measurement equipment is the internationally advanced Siemens electromagnetic flow meter. The flow measurement section can be equipped with pool flow disturbance devices, water inlet obstacles, and different types of integrated gates for measurement and control, as well as different sizes of guide channels and energy dissipation grids behind the flow measurement equipment. The return water system consists of water pumps, a rectangular pool, a flow measurement section, return water channels, and a stilling pool. The testing platform for the integrated measurement and control gate is shown in Figure 1.  
The flow measurement device is a box culvert integrated measurement and control gate flow meter produced by a certain company, as shown in Figure 2. The opening size of the measurement box is 600 mm \(\times\) 600 mm, the maximum water retaining height is 1500 mm, the width of the frame is 862 mm, the overall height is 2088 mm, and the length of the measurement box is 707 mm. Based on the 16 pairs of ultrasonic probes arranged in the flow measurement box, the ultrasonic time difference method is used to calculate the layer velocity of water flow in each layer of the flow measurement box, and then the flow speed area method is used to calculate the total discharge. A total of 30 gate flow measurement tests were conducted using the flow measurement device under different operating conditions, with a discharge variation range of 110-2500 m\({}^{3}\)/h and a gate opening variation range of 100-590 mm. In order to ensure the accuracy of the data and the stability of the water flow through the gate and to eliminate the measurement error caused by changes in the gate opening, each gate opening and given discharge were stabilized for 30 min, and 15 sets of data were continuously obtained. A total of 450 data sets were obtained as training samples for all working conditions. Subsequently, nine sets of gate overflow tests were conducted within the same range of flow and gate opening variations, and a total of 135 sets of data were obtained as prediction samples.  
Figure 1: Test platform for integrated measurement and control gate detection: **(a)** flow measurement test site and **(b)** layout plan of the testing device.  
Figure 2: Box culvert integrated measurement and control gate.