2003 – The Use of the Watt Inclinometer for Observing the Face Deflections of Concrete Faced Rockfill Dams

Arthur Yapa, Tom Bowling and Peter Watt

Hydro Tasmania uses an electronic inclinometer to monitor the face deflections of nine of its CFRDs. The inclinometer is lowered down a steel pipe attached to the upstream face of each dam. The inclinometer was designed and constructed by the University of Tasmania and was first used on Cethana Dam when it was completed in 1972.

The success of its use on Cethana Dam lead to its use for the long term monitoring of eight subsequent CFRDs constructed by Hydro Tasmania.

After 25 years of successful operation some irregular readings of face deflection became apparent. This paper describes the investigation of the irregular readings that had been obtained, the assessment of other methods of observing concrete face deflection, and the refurbishment of the inclinometer using modern electronic components.