The Lower Peirce Reservoir is one of the oldest reservoirs in Singapore. It is located near MacRitchie Reservoir and Upper Peirce Reservoir. Previously known as Kallang River Reservoir and Peirce Reservoir, it was renamed Lower Peirce Reservoir after the creation of Upper Peirce Reservoir. It has a surface area of 6 hectares and the surrounding forest contains many trees that are over 100 years old. There is a Lower Peirce Trail, which is a 900-metre boardwalk that takes visitors through a mature secondary forest. The reservoir is the source of the Kallang River, the longest river in Singapore.HistoryOriginally known as the Kallang River Reservoir, Singapore's second reservoir was impounded across the lower reaches of the Kallang River in 1910. In 1922, it was renamed Peirce Reservoir in commendation of the services of Robert Peirce (engineer), who was the municipal engineer of Singapore from 1901 to 1916.In 1975, a major water supply project to develop new water resources was undertaken to support Singapore's rapid housing and industrialisation programmes. A dam was constructed at the upper reaches of the Peirce Reservoir, forming the Upper and Lower Peirce Reservoirs.