The dam is 25 m (82 ft) tall, 900 m (3,000 ft) long and made of 120,000 m3 (4,200,000 cu ft) of concrete. The aggregate for the concrete was derived from volcanic rock in nearby areas. It has a circular axis of 200 m (660 ft) and its arch like design was used for stability. Hardly used, it's reservoir has a normal volume of 1,200 m3 (42,000 cu ft) and surface area of 1 km2 (0.39 sq mi). The dam's reservoir used to be a popular recreational area. Silt accumulation in the reservoir along with raw sewage being dumped upstream halted water supply from the dam in 1994. Since then, efforts have been ongoing to remove the polluted silt from the former reservoir bed. The area behind the dam will also be restored into a park once complete. Before being mostly emptied, the reservoir's elevations above sea level were 906.25 m (2,973.3 ft) at full capacity, 900 m (3,000 ft) at two-thirds capacity and 895 m (2,936 ft) at half.