The Steenbras Water Treatment Plant is situated on the Cape Town (West) side of the Hottentots Holland Mountains. The water treatment plant was completed in 1946 and has a capacity of 150 Mℓ/d.
The water treatment plant is supplied with raw water from Steenbras Lower Dam via a 752 m long tunnel through the Hottentots Holland Mountains.
Potable water from the Steenbras Water Treatment Plant is distributed through 3 bulk pipelines, namely:
A. the Steenbras 840 mm diameter main: This pipeline is a bitumen lined steel pipeline feeding Newlands Reservoir with the booster pump station at Garlandale. The capacity of the pipeline is 91 Mℓ/d when Garlandale pump station is utilised. The capacity is 50 Mℓ/d without the booster pump station being operational.
B. the Steenbras 815 mm diameter main: This is a cement mortar lined steel pipeline that supplies Newlands No. 1 and Wynberg No. 2 Reservoir through a 915 mm diameter branch pipeline. The pipeline is 53 km long and was designed to deliver 45,5 Mℓ/day. With Kildare Booster Pump Station operating the capacity is increased to 91 Mℓ/day.
C. the Steenbras 760 mm diameter pipeline: This is a 63 km long cast iron pipeline from Steenbras Water Treatment Plant to the City of Cape Town’s Molteno Reservoir. Delivery directly to Molteno has been discontinued and the pipeline is currently isolated and used as a distribution pipeline.
Refer to Figure 1 for the layout of this water supply infrastructure.
The treatment process used at Steenbras Water Treatment Plant consists of coagulation, flocculation, horizontal flow settlement, gravity sand filtration, stabilisation and chlorination.