The general problems of breaking arched dams and the construction of triangulation networks as a planned basis for breaking arched dams are considered. The specific conditions in which these triangulation networks (narrow and deep valleys, the development of coasts by explosion, etc.) have to be created are given, and practical recommendations are provided that facilitate more rational placement of points and determination of their coordinates with proper accuracy. The technique of calculating the required accuracy of the triangulation construction based on the given error in the displacement of the corner points of the portable panel formwork, which is installed during concreting of the arch dam units, is given.