The dam was built in stages between 1909 and 1918 in connection with the hydroelectric power plant in Tyssedal and the factories in Odda.

The dam is crowned by the date and initials of managing director Ragnvald Blakstad and topped with merlons in Neo-Romanesque style.

Ringedalsvatnet is today the reservoir of Oksla Hydroelectric Power Plant at Sørfjorden.

The reservoir has a capacity of 426 million m³ and the power station is every year producing approximately 900 GWh.

In 1903, three years before AS Tyssefaldene was established, the first underwater tunnel that pierced into the natural lake reservoir was made by the drill and blast method.

Later Bruuns Tunnel was made bigger and today a penstock pipe lifts the water from Skjeggedal Pumping Station to Ringedalsvatnet (pumped-storage hydroelectricity).

When the first stage of Tyssedal Power Station was built from 1906 to 1908, there was no need for a dam and reservoir.

AS Kristiania Monier og Cementvarefabrik and AS Høyer-Ellefsen were responsible for the construction of the dam.

The new plate was constructed two meter upstream from the original granite wall and horizontally supported by 1,700 beams.

It consist of 68 sections with 1 horizontal and 38 vertical expansion joints with plates of copper, bitumen and asphalt.