Survey Control for Concrete Dam Construction

The development of survey controls for Morrow Point Dam, a double-curvature, concrete-arch structure, 465 ft in height, was required through the phases of reconnaissance, site investigation, and preconstruction to satisfy the specific needs of the designer, and to fit the rough terrain. Statistics for the dam and power plant are given. Procedures and equipment used in establishing a modified second-order triangulation scheme and a first-order level net are explained. The method used in adjusting the triangulation scheme is presented. Planning survey controls to encompass specific structures was completed early in the construction phase. A description of survey procedures to bring accurate control into the blocks of the dam for each 7-1/2-ft placement-lift is given. Methods devised and equipment used in establishing vertical control in each keyway are described. A brief evaluation of planning field surveys to utilize modern electronic computing equipment is presented.