Upper Seletar Reservoir, Singapore’s impounding reservoir, was built to cater for the surge in water demand after World War I. Completed in 1940, it was damaged during Japanese air raids in 1941 but was subsequently repaired. In 1969, the capacity of the reservoir was enlarged by over 35 times. It was officially opened on 10 August 1969 by Princess Alexandra when she represented Queen Elizabeth II during the 150th anniversary celebrations of Singapore’s establishment as a British trading post. In 1981, the capacity of the reservoir was increased by another 13 percent. Originally known as Seletar Reservoir, the reservoir was renamed Upper Seletar Reservoir after the construction of the Lower Seletar Reservoir in 1986.