PIPELINES & LEAK DE TEC TION
WC/WDM: Starting with the basics While reducing municipal water losses is not complicated, there is no single water conservation and demand management (WC/WDM) intervention that will always provide the best savings at the least cost. Instead, a dedicated and methodical approach is needed to achieve real and sustainable savings.
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outh Africa’s National Water and Sanitation Master Plan (NW&SMP) highlights the fact that the country could face a projected 17% water deficit by 2030. Essentially, if demand continues to grow at current levels, the deficit between water supply and demand could be between 2.7 and 3.8 billion m3/annum by the end of the next decade. As South Africa faces increasing water stress, WC/WDM will have a key role to play in ensuring long-term water security. Dr Ronnie McKenzie, former chairman of the IWA Water Loss Specialist Group, notes that many municipalities struggle to reduce the often-high levels of water losses in their reticulation systems. McKenzie has written a guide to the reduction of water losses from municipal water supply systems, which is available freely from the Water Research Commission. Many of the issues discussed below have been summarised from his report*.
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Dealing with losses The NW&SMP points out that 35% of municipal water is lost through leakage, resulting in an annual loss of around 1 660 million m³. At the current average unit cost of over R10/m³, this amounts to approximately R17 billion in losses for municipalities throughout South Africa each year. Given the fact that many municipalities are dealing with billions in lost revenue due to the economic impacts of the Covid-19 pandemic and subsequent lockdown, addressing water losses presents an opportunity to reduce financial losses. And for municipalities facing drought, such as those in the Eastern Cape, it presents an ideal opportunity to recover much needed water resources. McKenzie notes that municipalities should begin with addressing the basic issues first. “Until the basic issues have been properly addressed, there is relatively little benefit to be gained by introducing some of the more expensive and sophisticated measures.” he notes. However, even addressing the basics requires a budget and real
effort from the municipality, often involving the excavation of pipelines and repairs where necessary. Where to start According to McKenzie, repairing visible and reported leaks (preferably within 24 hours) is one of the most obvious and basic interventions that should be implemented as a top priority. “The repair of such leaks needs no financial justification or preliminary assessment to determine if it is worthwhile. It is the most obvious and cost-effective measure that any municipality can undertake and will always be worthwhile.” However, active leakage control (searching for below-ground, unreported leaks) is not always costeffective. While it may be worthwhile in an area known to have high leakage or dolomitic areas where leaks will never surface, visible leaks should be repaired Underground leak running at low pressure (Credit: Ken Brothers)
