This article discusses the results of field research to determine the deformation of the base of a low-pressure hydraulic structure that has been in operation for a long time. On the basis of geodetic measurements, a longitudinal profile of the settlement of the body of the structure was constructed, which ensures the safety of the foundation of the structure. A technique for carrying out field studies is presented, which makes it possible to control the deformation of the base in low-pressure hydraulic structures.