Leading water management expertise helps create resilience By Benjamin Biggs

JG Afrika JG Afrika





The severe arid conditions have played a large part in motivating the importance of water-management projects in the country.

JG Afrika’s expertise in the field remains in high demand, especially in drought-stricken Western Cape where policies have been implemented that promote flexible water-supply solutions.
The success of our many projects can be attributed to a number of factors, not least of which is our multi-disciplinary skills and capabilities.

This allows us to explore all of the various components of the urban-water cycle in our water-sensitive designs.

We are, therefore, able to provide a diverse source of supplies to increase resilience, as opposed to the isolated approach taken on so many water-management programmes in the past.

In addition, emphasis is placed on matching the quality of the water to suitable applications in a significant departure from traditional thinking where high-quality drinking water is still being used to flush toilets and for irrigation purposes.
The initial phase of our water-management plans focuses on first understanding water use to reduce demand.

Our experience has shown that this upfront work can play an important role in mitigating, or even eliminating the need for more costly and longer-term measures.

For example, our first phase of interventions at an international school reduced water demand by 60%.

They were selected based on the findings of a comprehensive baseline assessment to model water flows on site. This allows us to understand end-use quantities for various applications and determine the site water balance, which is the flow of water in and out of a system.

The next phase of our projects will entail reusing the water on site by installing a rainwater harvesting system with treatment.

Combined with those actions undertaken during the initial phases, this step will reduce the school’s reliance on municipal water supplies by up to 95%.

Depending on rainfall levels in the winter period, the school may decide to install a borehole to replenish stores of harvested water in the tanks.

The combined three phases will result in cost-savings of R150 000 per year when water restrictions were applied and R300 000 per year after the dry period, while the school will be able to recuperate its investment in three to four years.

At the University of Stellenbosch, the first phase of our water plan resulted in a 25% saving in total campus water use and 40% of residence use.

State-of-the-art methods were deployed to accurately identify where water is being used on campus and then to quantify the demand for the resource in specific applications.

These actions taken during the water modelling were the focus of an academic paper that was prepared by the university and JG Afrika.

They included the installation of temperature sensors in some of the facilities to measure shower durations and water warm-up time in two of the residences.

Our analysis revealed that bathing and showering accounted for as much as 25% of the total campus water use and 40% of residence use, and appropriate action was taken to significantly reduce demand.

The next phase entailed capturing storm water runoff and recycling large volumes of recycled water from other applications to be used for irrigation. Meanwhile, the drought has also elevated the importance of water in sustainability programmes. In the past, water, energy and waste management were often undertaken in isolation of one another.

A sound example of such a project is our award-winning sustainable interventions at Bayside Mall on behalf of a leading property developer.

Harvesting of rainwater and use of storm water runoff has allowed the mall to achieve a 90% water savings in landscaping and public toilet use, while rooftop photovoltaic and anaerobic digestion technology has significantly reduced its reliance on municipal electricity supply.

I am also proud of our own DSM programme at our office in Pinelands that we implemented as early as 2011.

Weekly readings confirm that we have reduced our water consumption by between 68% and 70% simply by installing water efficient technologies during the first phase of the demand-side management programme. We will be taking further steps in the short-term to enhance this performance.

Benjamin Biggs is a civil engineer and urban water-management specialist at JG Afrika. Biggs reports to both the municipal infrastructure and sustainability divisions of JG Afrika’s Cape Town operations. Headed by Harold Tiganis and Sally-Anne Käsner, these divisions continue to experience a high demand for their combined skills and capabilities.