水利水电工程中的大坝、隧洞、水库,大都位于高山峡谷地区,坡度陡,比高大,通行困难。而坝址、隧洞及其进出口地区,往往要求地形测图比例尺大,基本等高距小,对高程测量的精度要求也较高。因此,在这些地区进行水准测量比较困难,速度也非常慢。在总结水利水电工程测量多年实践经验的基础上,《水利水电工程测量规范》已明确规定:“当 Dams, tunnels and reservoirs in water conservancy and hydropower projects are mostly located in mountain valleys with steep slopes and higher than normal height. The dam site, tunnels and their import and export areas, often require topographic mapping scale, the basic contour is small, the accuracy of elevation measurement is also higher. Therefore, leveling in these areas is more difficult and slower. On the basis of summarizing the years of practical experience in water conservancy and hydropower project measurement, the “Specifications for the Measurement of Water Conservancy and Hydropower Engineering” has clearly stipulated: "When