Timothy Irvine, the regional asset manager for the Western Cape at Growthpoint, said The District in Woodstock in Cape Town had become the group’s first “water net-positive” building and was the first of several commercial properties in Cape Town they intended to take off the grid.
Irvine said by taking The District and other commercial buildings off the water grid and substituting municipal water with a safe and sustainable alternative source of drinking water, they were taking pressure off the city’s potable water reserves.
The District, a multi-tenant office and retail building, has seven floors and five basement levels with 18721m² of lettable area that accommodates 25 businesses. It was used by about 1750 people daily, who collectively consumed about 45000 litres of water a day.
Irvine said the next building Growthpoint planned to take off-grid was 200 on Main, adding that all the buildings it had identified to take off the water grid were in Cape Town because it was the only city with the legislation in place to enable it.
“Growthpoint would certainly consider doing the same with suitable buildings in other cities and is happy to work with them to achieve this,” he said.
Irvine said Growthpoint had worked with the City of Cape Town to get special legislation drafted and passed to allow it to produce water on a large scale and also had to get buy-in from the tenants of The District.
He said the legislation the City of Cape Town drafted came into effect in November last year, when Growthpoint was given the permission to become a water services intermediary.
However, Irvine said Growthpoint could only supply water to those with which it had a contractual obligation, its tenants, and it did this at exactly the same rate as the municipality.
A naturally occurring underground mountain spring flows to The District’s basement. To prevent flooding, this crystal-clear water was for years pumped from the basement sump into the city’s stormwater system, from where it flowed into the sea less than a kilometre away.
Irvine said Growthpoint identified and adapted an existing technology to use the sump to provide drinking water that was completely safe for human consumption for the entire building.
About 140 000 litres of water flows naturally through the sump each day and the filtration plant had been designed to clean the entire flow.
David Green, the chief executive of the Victoria & Alfred (V&A) Waterfront in Cape Town, confirmed in January that Growthpoint and the Public Investment Corporation, the equal joint owners of the V&A Waterfront, aimed to have a desalination plant operational by next year to provide water for the precinct and mitigate the risk to their investment caused by city’s water shortage crisis.
The desalination plant would produce between 3.5million and 5million litres of water a day and cost about R200million.