CPG was awarded two contracts C1 and C2 by the national water agency PUB to construct the 2.2 km long Stamford Diversion Canal (SDC) starting near the Tanglin Road-Grange Road junction. The SDC will divert stormwater from current Stamford Canal along Orchard Road to Singapore River; and will protect the dense urban infrastructure and communities in the area. It is constructed beneath existing roads along Grange Road, through Hoot Kiam Road, Irwell Bank Road, River Valley Road and ending at Singapore River off Kim Seng Road.

The first, Contract 1 (C1) – Tanglin and Kim Seng, involved construction of an underground double cell box culvert covering a distance of approximately 600m, along River Valley Road. It connects to Singapore River by cut and cover method.

The second Contract 2 (C2) – Grange Road to River Valley, connects both sides of the SDC at the front and end section. It runs along Grange Road by tunnelling method and runs across Hoot Kiam Road and along Irwell Bank Road by cut and cover method. The cut and cover comprises approximately 600m long single and double cell box culverts. The tunnelling comprises 24m diameter launching shaft. The extent of the bored tunnel includes a 4.5m diameter twin tunnel with two access chambers and one maintenance access at each tunnel. The access chamber sited offline of tunnel and connected by cross passage by pipe roofing method. There are also twin 2.5m diameter pipe culverts connecting to the launching shaft.