Picture: Supplied

JOHANNESBURG - The area of Greater Cape Town could cost-effectively tap two months of new water supply a year by clearing non-native trees from water catchments, a report from conservation group The Nature Conservancy published on Friday shows.

The study says 'engineered’ options to tackle the effects of drought like desalination plants or reusing wastewater are on average ten times more expensive than removing pine, acacia and eucalyptus trees, commonly called ‘invasive alien plants’ or ‘invasives’.

Its findings formed part of the business case for a new public-private mechanism to finance water security, the Greater Cape Town Water Fund, launched in Cape Town on Friday and supported by Coca-Cola, PepsiCo, Caterpillar Foundation, and Levi Strauss & Co., among other companies.

In total, close to R53 million has already been committed to the find, which is also backed by provincial and national authorities.

“In order to secure our long term water supplies, we need to pursue a range of cost effective strategies," Cape Town deputy mayor Ian Neilson said.

"One of those is to clear vegetation in our catchments that reduce the runoff into our dams, such as that proposed by The Nature Conservancy in this report.”

Dams supplying Cape Town are three-quarters full after the first season of adequate rainfall following three years of record lows. The city faced blanket water rationing in 2017, with households limited to 50 litres per person per day while severe restrictions were imposed on agriculture and industry.

The Nature Conservancy study found that R372 million could fund a 30-year programme to clear invasive trees and prevent them from returning in the seven priority sub-catchments that supply three-quarters of Cape Town’s water.

As well as being cheaper, this ‘green’ option would deliver more new water than each of the other options.

The Fund’s steering committee will now work on a strategy for ecological restoration of the Western Cape water supply system, focusing on clearing invasive plants from seven priority sub-catchments that together provide 73 percent of the system’s water.

This is expected to create at least 350 new jobs in the first six years, mostly to make up teams to clear the invasive plants.

Preliminary analysis shows that an estimated 1.8 billion litres of water is lost annually due to alien plant invasions on the Atlantis Aquifer north of Cape Town.

A year-long research project is already underway with a pilot team clearing invasive plants to determine their impacts on groundwater.

An estimated 70 percent of the aquifer’s surface area has some level of invasion, with nine percent of the area densely invaded.

The Nature Conservancy is a global organisation focused on tackling climate change, conserving lands, waters and oceans, providing food and water sustainably and helping make cities more sustainable. It works in 72 countries, engaging local communities, governments, the private sector and other partners. 

- African News Agency (ANA)