This United States Army Corps of Engineers publication, Engineering Manual EM 1110-2-1009 Engineering and Design: Structural Deformation Surveying February 2018, provides technical guidance for performing precise structural deformation surveys of locks, dams, and other hydraulic flood control or navigation structures. Accuracy, procedural, and quality control standards are defined for monitoring displacements in hydraulic structures. This manual applies to all U.S. Army Corps of Engineers (USACE) Commands having responsibility for conducting periodic inspections of completed civil works projects.