## 4 Discussion  
As a large-scale water conservancy project in China, the South-North Water Diversion Project plays an important role and safety monitoring is a key task, but due to its huge construction, a large-scale and high-precision deformation monitoring technology is urgently needed. The results of several studies show that its monitoring accuracy can reach a millimeter level, which can accurately reflect the deformation of the ground feature. Therefore, this paper uses this technology to monitor the deformation of the high-fill canal section of the South-North Water Diversion points out the areas with serious deformation and studies the feasibility of applying PS-InSAR technology to large-scale water conservancy projects.  
According to the above study, it is shown that the application of PS-InSAR technology can effectively monitor the deformation of the high-fill canal of the South-North Water Diversion Project. The accuracy of PS-InSAR monitoring effect is evaluated in combination with the second order leveling data, which proves that PS-InSAR technology can provide accurate monitoring results. Compared with conventional measurements, the use of PS-InSAR technology has the advantages of high accuracy, wide range monitoring, and flexible observation. In this paper, we used PS-InSAR monitoring results to make a cross-sectional analysis of the key deformation areas of the South-North Water Diversion Canal. According to the longitudinal section analysis, the overall deformation of the canal is small. However, there are four areas with severe deformation at the same time. According to the cross-sectional analysis, the west bank of the canal is more stable, the east bank of the canal shows an obvious downward trend, and the closer to the water, the larger the canal deformation is,  
Figure 11: PS-InSAR deformation monitoring results of high fill canals at different periods. (a) December 2016–June 2017 (b) December 2016–February 2018.  
and vice versa, the smaller the deformation law is. The canal can cause greater variability in the shape of the canal close to the canal due to the presence of water flow over a long period of time, while further demonstrating the reliability of the technique and realistic response to the deformation state of the canal.  
The use of PS-InSAR technology can provide more means to monitor the deformation of large water conservancy projects and can analyze the deformation of water conservancy projects in all aspects, as well as the overall deformation status of key areas. No settlement occurred on the west bank of the canal during October 2016 to June 2017, and based on further processing of the collected image data, it was found that the canal also experienced settlement on the west bank over time, with greater deformation on the east bank compared to the west bank. At the same time, using PS-InSAR technology, it is possible to find out the historical deformation and the development trend of deformation and be able to make an accurate response. The study helps managers to understand the deformation characteristics and key deformation areas of the South-North Water Diversion Canal. Through systematic analysis, the settlement mechanism of the Ye County section of the Middle Route of the South-North Water Diversion Project is analyzed and the locations that need to be monitored are pointed out.