Eastgate Shopping Centre’s rainwater harvest system
In an effort to ensure sustainability and reduce the impact of water outages, Eastgate Shopping Centre has contracted black-owned contractor Concor to install a facility to harvest and treat rainwater and groundwater.
The new facility comprises two segmented steel tanks capable of storing about 200 000 l of water. Rainwater runoff from the rooftop parking area – which currently runs into the city’s stormwater drains – will be piped into the tanks. This will be supplemented by groundwater resources under the centre which will be pumped up and stored. The tanks are linked by a 300 m water line to the centre’s existing buffer tank.
In preparation for the work, Concor excavated test pits to ascertain the presence of services, piping or ducting – as accurate as-built plans were not available. In addition to uncovering various services, the test pits also revealed a concrete crane base some 500 mm in depth, which had to be removed before foundation works could begin.
Geological conditions called for the use of twelve 130 mm micro-piles to ensure the stability of the tanks, following which raft foundations were cast over a 5 m x 10 m area. Construction of the foundations and the tanks is in close proximity to an existing liquefied petroleum gas chamber that serves tenants such as restaurants in the centre. This requires special attention to health and safety procedures, including regulated permissions and certain restrictions on the use of electrical equipment in the area, explained Concor.
The project includes the installation of filtration and treatment facilities, ensuring that the water is potable for use throughout the centre.