Completed in the late 1860s, it was part of the first public water supply system implemented in Singapore. The Impounding Reservoir, as it was the known, came about through the generous financial contribution of a Straits Chinese merchant, Tan Kim Seng. In 1907, it was named Thompson Road Reservoir and renamed MacRitchie Reservoir in 1922 after James MacRitchie, the Municipal Engineer of Singapore from 1883 to 1895. Over the years, the reservoir was enlarged twice to keep pace with the rapidly growing demand for water due to the increase in population and the expansion of commercial activities in the town.