Geopartner boasts of the first experiment in Poland for GPR underwater application: on behalf of Toruń Energy Department, through the use of a purpose-built bathyscaphe, was conducted a detailed study of the conditions of the concrete slab and the ground below at hydroelectric power plant in Włocławek. The results of this study open up new opportunities for the diagnosis of geotechnical and structural conditions of seemingly inaccessible areas of hydraulic structures. Other methods of investigation experienced in the past have proved to be too expensive or extremely complicated or unsatisfactory resolution; tests carried out have instead demonstrated the reliability of GPR method, mainly able to ensure analytical accuracy and an economic impact compatible with the monitoring goals of underwater portions of hydraulic structures.