What measurement methods are used in dam safety supervision?

The subject of interest for the dam safety supervision is mainly the seepage regime and deformations of the dams and their subsoil. The seepage regime is monitored mainly by measuring the amount and turbidity of leaks at the outlet of drainage drains, on cracks and expansion joints, by measuring levels in observation wells, pressures in pressure wells and by using pore pressure sensors. Special deformation measurements include measuring on deformetric and clinometric bases, borehole inclinometric measurements, extensometers, pendulums and using geodetic methods such as very accurate leveling and trigonometric methods and other up to date geodetic methods such as ATR (automatic targe recognition). Temperatures of water and structure are measured as well.