The other half cannot be used for two reasons, either they are too densely populated or they are industrial areas where the water would be polluted.

PUB’s Water schemes:

1. Upper Peirce Scheme

A dam was constructed at Lower Peirce Reservoir in 1975

2. Kranji/Pandan Scheme

Kranji Reservoir was created after the construction of a dam at the estuary of Kranji River. Pandan Reservoir was formed when a mangrove swamp was enclosed by a dyke.

3. Western Catchments Scheme

Four reservoirs were formed in the west when dams were constructed in four rivers – Murai, Poyan, Sarimbun and Tengeh.

4. Sungei Seletar/Bedok Scheme

Sungei Seletar was converted to Lower Seletar Reservoir in 1986 after damming works were completed.

Also, a man-made reservoir, Bedok Reservoir was created from a former sand quarry.

At the same time, a water treatment plant, Bedok Waterworks was constructed next to the reservoir. The special characteristic of Bedok Reservoir is that its source of raw water is from stormwater collection stations set up in new towns to collect storm runoffs.