Civil Engineering nOVEMBER 2021 | Vol 29 No 10

12 November 2021 Civil Engineering based on 132 data sets out of a potential 237 municipalities. These 132 data sets included all of the metros and large cities, covering almost 85% of all piped domestic water in South Africa. The data showed an average for NRW across the country of 36.8% in June 2010. The data is further broken down into four categories: metros (A), secondary cities (B1), large towns (B2), small towns (B3) and rural areas (B4). The results show that B2 municipalities performed the best with an average NRW of 30.5%, while B4 municipalities performed poorly with an average NRW of 72.5%. A, B1 and B3 municipalities had an average NRW of 34.3%, 41.3% and 37% respectively. “What this tells you is that in the metros we have high-value, low-cost water because of the economies of scale, but in the rural areas we have high-value, high- cost water because of the complexities of transporting water across the spatial settlement patterns of rural areas,” said Bhagwan. However, he went on to highlight that, although rural municipalities have much higher NRW than the other categories of municipalities, the population size means that the litres/capita/day (ℓ/c/d) consump- tion is much higher for urban areas than rural areas. In 2010, the NRW of 36.8% translated into a cost of more than R7 billion per annum. Bhagwan believes that today it could be closer to R15 billion to R20 billion per annum given inflation and the rising cost of water. “We haven’t been able to arrest this issue of NRW significantly at a national level,” said Bhagwan. In the 2015/16 National Water Balance, national NRW jumped to 41%. Examining the breakdown per province, most provinces reported NRW of more than 45%. Limpopo was the worst performing province with 55.1% NRW while the Western Cape had the lowest NRW at 21.3%. As much as 70% of all domestic water supplied in the country goes to the metro areas, which is where Bhagwan believes the opportunity lies to tackle the NRW challenge. “If you can solve that, you can reduce this equation in a significant manner,” he said. “It is a matter of where you put your full might in tackling this and it should start with the A and B1 municipalities if you want to make a big dent.” However, Bhagwan cautioned that although the metros are not showing a decline in NRW, the bigger concern is the B1, B2 and B3 municipalities. Table 1 shows the changes in NRW between 2010 and 2016 and highlights the significant jump in NRW experienced in these areas. A WORD OF CAUTION As water shortages increase, many water suppliers are introducing intermittent supply as a means of reducing water losses at night. Bambos Charalambous, past chairperson of the IWA WLSG and the IWA Intermittent Supply Specialist Group, noted that this is especially the case in areas where suppliers are not receiving payment for water, and in some cases, they are cutting off whole towns to try and encourage payment. “This prac- tice is the worst thing that can happen,” stated Charalambous, who highlighted the dangers of intermittent supply which in fact leads to greater losses and possible disease outbreaks if the water supply gets contaminated with polluted groundwater during the zero pressure periods. Many towns and cities around the world are facing their own Day Zero in cases where severe droughts are occurring. Delegates heard about how Cape Town is probably one of the best examples in the world where a major city (with a population of around 4 million) managed to steer itself through the worst drought in over 200 years, avoiding a Day Zero. Peter Flower, recently retired director of the City of Cape Town’s Water and Sanitation Department, who was in charge of the Cape Town water crisis, explained what works and what does not work when a city faces the real threat of running dry. “Cape Town is the only major city in the world that has managed to reduce its water use by half without resorting to intermit- tent supply and the lessons learned should be of great interest to any city facing water supply issues,” he said. ADDRESSING NRW Bhagwan ended his presentation with a list of recommendations and insights: Q Q Reducing water loss starts with a proper perspective. In distribution sys- tems that do not yet have permanent infrastructure monitoring for active leaks, even the approach to evaluating such infrastructure requires a new perspective. Q Q For operations management and deci- sion makers experiencing high water costs, real and apparent NRW losses, water scarcity, or rapid growth, the need for change is obvious, but the cost of it raises concerns. Q Q Affordable strategies for leak detection and repair do not necessarily require all-or-nothing capital investments. Utilities can take a tiered approach to investing in solutions that will help them identify and remediate their most egregious risks for real water loss first. Q Q Whatever the approach, a fundamental aspect of cost-effective leak detection Table 1 KPI trends in NRW (Source: Jay Bhagwan, presentation at the 2021 South African IWA Water Loss Specialist Group Regional Summit) State of NRW in SA (2009/10) 3% No Drop (2012/13) 2015/16 National Benchmark Category No % NRW ILI ℓ/c/d No % NRW ILI ℓ/c/d No % NRW ILI ℓ/c/d A 8 34.3% 8.2 291 8 32.3% 5.4 280 8 34.4% 5.3 283 B1 18 41.3% 7.4 241 15 41.5% 6.5 261 19 48.1% 5.9 260 B2 26 30.5% 5.7 230 15 26.2% 4.8 321 25 44.3% 4.4 204 B3 55 37.0% 4.7 164 49 37.1% 4.2 217 100 52.7% 4.2 172 B4 25 72.5% 7.8 65 14 49.5% 4.0 90 61 49.6% 3.4 158 Total 132 36.8% 6.8 235 101 34.6% 6.2 252 213 41.0% 5.3 233