Comprehensive measurement method of farmland irrigation water utilization coefficient Posted by : admin / Posted on : Jul 19， 2019

The irrigation water utilization coefficient is a key indicator to measure the water saving effect of agriculture. The analysis, comparison and evaluation of any water-saving technical measures cannot leave the irrigation water utilization factor. However, the irrigation water utilization coefficient given by local and irrigation districts in China is difficult to compare and measure. From various regions, the current statistics on the utilization coefficient of irrigation water vary greatly, and many data are obviously wrong. The main reason for the normal measurement of irrigation water utilization coefficient is that the traditional measurement method has huge measurement workload and difficult to determine measurement conditions. It is urgent to analyze the irrigation water utilization coefficient. The comprehensive measurement calculation method is proposed on the basis of analysis and research. It not only overcomes the shortcomings of traditional measurement methods, but also requires a lot of manpower and material resources to complete. It also makes up for the shortcomings of measuring only typical canals and causing large errors. And it can reflect the water use of the canal in the irrigation area, the quality of the irrigation project and the management level of irrigation water. It provides a practical and feasible method for calculating the irrigation water utilization coefficient and guiding the water-saving project reconstruction in the irrigation district in the future.
Typical channel selection and requirements
Choose a representative typical channel
  Typical channels should include lining channels and unlined channels. The project integrity rate is close to the engineering integrity rate of the lining and unlined channels in the whole irrigation area. The water flow rate is close to the average value of the channels. The typical completion rate and over-water flow of a typical canal should be close to the average of typical channels.
Selection of flow measurement section
  Where the channel section is straight, the water flow is uniform, there is no vortex or backflow, the section should be perpendicular to the direction of the water flow. The flow section should have a section with a stable rule. Comprehensively and conscientiously inspect the planned channels, remove the sediments and stones near the water-measuring section, and keep the flow-measuring section intact and unobstructed.
Choice of measurement method
  When measuring, try to use flow meter and water meter to measure flow. When using other methods, use flow meter to determine.
Measuring condition requirement
  Flow and water should be measured under actual irrigation operating conditions. The water distribution in the measuring section is normally divided, and the flow of the channel (channel) during the measurement period should be as stable as possible.
Measuring the number of channels
  In order to reduce the workload, sampling measurements can be taken, and the lining and unlined channels are measured separately. The channels at each level are determined according to Table 1.
Measuring typical length requirements
  When the flow rate is less than 1m3/s, the length of the canal is not less than lkm; when the flow rate is 1~10m3/s, the length of the canal is not less than 3km; when the flow is l0~30m3/s, the length of the canal is not less than 5km; the flow is greater than 30m3 When /s, the length of the channel is not less than 10km.
flow measurement