Reduction of Non-Revenue Water in Limassol, Cyprus
The water utilities of Cyprus supply an increasing number of consumers under worsening hydrological conditions, topped with adverse seasonality. For the past two decades, there have been two serious drought periods: between 1996 and 2000, and in 2008–2009, when only intermittent drinking water supply was feasible. Water is extremely precious in such conditions, and the Water Board of Lemesos (WBL) has made major efforts to reduce non-revenue water. The WBL successfully developed and implemented a strategy to reduce NRW, based on the creation of 60 so-called “District Metering Areas” (DMAs), sophisticated pressure management, leak monitoring, and a specialised team to explore and quickly repair pipe ruptures. As a result, NRW declined from about 25–27 percent to around 15—17 percent within just two decades.
- This case study is about the reduction of technical water loss at the Water Board of Lemesos (WBL) in Cyprus.
- Annual precipitation in Cyprus is highly variable (as depicted in the following graph), and the country is exposed to substantial water stress during dry years. Climate change models predict more frequent periods of drought for the island, due to the combined effect of higher summer temperatures and declining overall precipitation. Therefore, water scarcity-related challenges are likely to intensify in the future.
- Annual precipitation in Cyprus (See image)
- Precipitation varies not only across the years, but there is also strong seasonality within the year. As the graph below shows, rainfall in Limassol (Lemesos in Greek) during the summer months is essentially zero. This period also brings the highest temperatures and the most intensive evaporation.
- Seasonality of temperature and precipitation in Limassol, Cyprus (See image)
- Water consumption is also seasonal, with most use taking place during the summer period; summer water use is about 20 percent higher than in winter.
- In addition, the population of Cyprus has steadily increased in recent decades, and has doubled in the past half-century. Bearing all this in mind, the main challenge facing WBL can be easily guessed at: supplying an increasing number of consumers under worsening hydrological conditions, topped with adverse seasonality (which is the situation facing most other MENA-region water utilities).
- In Cyprus, each municipality has its own water authority (water utility) that sets its own water tariffs. The Water Board of Lemesos supplies a population of about 160,000 through a total of almost 90,000 connections (residential and non-residential combined) in the south of the island. All customers are metered, and all properties have rooftop tanks for local water storage.
- Since Cyprus has taken advantage of essentially all economically feasible supply-side measures, it now needs to focus its attention on demand-side solutions, a key component of which has been the reduction of non-revenue water (NRW). The WBL has adopted and successfully executed a long-term strategy of NRW reduction. As Figure 3 illustrates, NRW fell from 25–27 percent in the late 1980s to 17 percent by 2007. Leakage increased again after the 2008–2009 drought, but this has a specific technological reason (explained below). The WBL’s long-term goal is to achieve a NRW rate of 8 percent.
- Time series of NRW at the Water Board of Lemesos (See image)
- In devising and implementing its NRW strategy, the WBL followed international methodologies. The key pieces of the strategy are described below:
- Nine pressure zones were created within the drinking water network, and each pressure zone is subdivided into District Metering Areas (DMAs). In total, there are 60 DMAs, each with its own storage reservoir and a single-metered source.
- Pressure management is applied to all DMAs. This is an important measure because excess pressure contributes to the attrition of the pipelines, while also increasing the volume of water lost through leaking sections.
- Meter readings from the water sources and key network points are connected through a SCADA system to a central control room, which provides constant information on water flows through the system. Nightly data is analysed to spot changes in water flows, which can be a sign of pipe bursts (nightly data is more suitable for this purpose than daytime data, because during the night most users have little or no consumption and network ruptures are easier to identify).
- Quick identification of leaks is made possible through the deployment of a permanent, well-trained team dedicated to leak detection and the procurement of the latest leak detection technology.
- A network repair policy has been designed and implemented in order to reduce the speed of intervention to less than a day. Most leaks are fixed on the day they are discovered. High-quality materials are used in repair to prevent future ruptures at the same location.
- The SCADA system can also provide useful information to identify sources of apparent loss, such as illegal connections or broken water meters.
- Network reconstruction programmes target those network sections that are most problematic based on pipe break records, assuming that the durability of the pipelines and connections is least satisfactory in these locations.
- As Figure 3 describes, NRW values increased after the 2008–2009 drought. During this period, water in Cyprus was so scarce that drinking water services were operated irregularly instead of the usual 24/7 supply. Because the leakage control system in such circumstances was difficult to operate, leaks were not detected and repaired as quickly as before. An analysis of the water balance before, during and after the drought period concluded that while intermittent supply saves water in the short run, on a longer time horizon it generates losses due to more leakage. On balance (if sufficient water is available to do so) it is better to continue with 24/7 supply, even at lower than usual pressure, than switching to intermittent water supply to save water.
- As a conclusion of the case study, the smart NRW reduction strategy implemented by the WBL is repeatable in other locations within the MENA region. Financial resources, while important, are not the sole means of implementing a successful NRW strategy: dedicated management and a well-organised and properly equipped leakage team are also crucial. Moreover, if a water utility does not face the true cost of its water input, the incentives to run a high-profile NRW strategy will be limited. Finally, if due to water scarcity there is only intermittent drinking water supply, as in Jordan, then the present case study may not be fully applicable.
- Non-revenue water (NRW) was already as low as 17 percent in 2007 (but the NWR level started rising again due to the drought of 2008–2009).
- Thorough, systematic implementation of international NRW reduction methodologies and measures.
- Percentage of non-revenue water.
The achievements of the WBL are certainly repeatable elsewhere in the MENA region. However, financial resources, while important, are not sufficient on their own to establish a successful NRW strategy: dedicated management and a well organised and properly equipped leakage-response team are also crucial. Moreover, if a water utility does not face the true cost of its water input, the incentive to run a high-profile NRW strategy will be limited. Finally, if water scarcity is the cause of intermittent drinking water supply—as in Jordan—the the present case study might not be fully applicable.
- Anastasia Sofroniou and Steven Bishop. “Water Scarcity in Cyprus: A Review and Call for Integrated Policy”, Water, 2014, 6, pp. 2898–2928.
- Stedman, Lis. “Water-scarce Cyprus leads discussions on utility management and pricing”, Water Utility Management International, March 2012. Volume 7, Issue 1.
- Homepage of the Water Board of Lemesos: http://www.wbl.com.cy/en/page/home
- “Good Practices on Leakage Management: WFD, CIS, WG, PoM”, European Union reference document, 2015.
- Charalambous, B. “Experiences in DMA redesign at the Water Board of Lemesos, Cyprus”. http://www.studiomarcofantozzi.it/Experiences%20in%20DMA%20redesign%20at%20the%20WBL.pdf
- Rita Hochstrat and Christian Kazner. “Flexibility in coping with water stress and integration of different measures”. Case study report on Cyprus. Techneau, 2009.
- Blinda, Mohammed. “More efficient water use in the Mediterranean”. Plan Bleu, Paper 14, 2012.