THE NECESSITY OF A STRATEGY TO CONTROL WATER LOSSES
A. C. Bowden* BSc, CEng, MICE, MCIWEM
* Managing Director, A C Bowden Consultancy Ltd, Five Gables, 90 Whitemoor Road, Kenilworth,
CV8 2BS, Warwickshire, UK
ABOUT THE AUTHOR
Andy Bowden is an International Water Utility Consultant who provides institutional support to water utilities worldwide. He has been associated with the Romanian water sector since 1994 providing technical assistance to a large number of water and wastewater utilities in the field of operational management. This has included the important area of non-revenue water (NRW) where he has worked closely with utilities, government departments, international financing Institutions and the Romanian Water Association in developing strategy and supporting implementation of water loss reduction programmes throughout the country.
It is a great pleasure for me to be asked to make a contribution to this magazine as I see it as being a forum for consolidating and building on the good work that has been done so far in Romania in addressing the issue of non-revenue water (NRW).
NRW constitutes a significant component of operating expenditure, particularly in Romania where water networks are, to a large extent, aging, are of poor quality materials and installed without an appropriate level of care or protection for long system life. This article highlights the benefits of having a proactive approach to reducing leakage and educating customers as part of an overall strategy that contributes to an overall reduction in NRW.
In Romania significant progress has been made in reducing levels of NRW but significant challenges still remain, particularly with the challenging targets that have been set for reducing NRW levels associated with Cohesion Fund investments.
PROACTIVE APPROACH TO LEAKAGE
The intention of introducing a proactive approach to leakage is to strike a balance between the cost of reducing leakage and the value of the water saved. The level of leakage at which it would cost more to make further reductions than to produce the water from another source is known as the economic level of leakage (EEL). Operating at economic levels of leakage means that the total cost of supplying water is minimised and companies are operating at optimum efficiency.
EEL is not fixed for all time as it depends on a wide range of factors. For example the cost of detecting and repairing leaks will reduce as new technology is introduced causing the ELL to fall. Conversely if water demand falls to a level such that there is a large surplus of water it may not become economic to reduce leakage.
An integral part of adopting a pro-active approach reducing levels of NRW is to know the starting point and to continually monitor performance. For this reason accuracy of the data used is of prime importance and an area where significant investment needs to be made in the field of metering to assure reliability. There are several components to the water balance that account for the total volume of water put into supply. These are, measured and un-measured domestic consumption, measured and un-measured non-domestic consumption, water taken billed or un-billed, either legally or illegally, water used for operational purposes and finally, distribution losses.
Unfortunately, leakage location still remains a far from exact science. Distribution systems can now be seemless, through the use of welded polyethylene (PE) pipe systems. Although the networks are now more robust than those of the past, it has made the pinpointing of leakages more difficult as those charged with locating water losses will tell you.
Reasons for repairing leaks
There are numerous reasons and benefits that can be realised for identifying and repairing leaks speedily as part of the proactive approach to leakage. These can be summarised as follows:
- leaks get bigger with age
- repairing leaks reduces water losses
- repairing leaks that are pre-identified can be approached in a planned way and reduce overtime rates
- repaired leaks ensure that more water is available to be sold to customers
- leak detection and repair reduce energy and chemical costs associated with the production of water
- leaks can cause damage to roads and buildings and have a negative effect on the environment
- active leakage detection and repair projects a good image to the general public
- a water company gains credibility by being seen as putting its own house in order before asking customers to conserve water
The prime requirement for implementing a proactive approach to leakage reduction is the establishment of district meter areas (DMA’s) supported by the use of new technology and a number of key initiatives. Such initiatives include the use of pressure reduction, computer modeling of water networks, priority response timing for identified leakage repairs.
The establishment of DMA’s is essential for good management of any water distribution network and readily aligns itself to a proactive leakage strategy. DMA’s are discrete areas of a distribution network comprising typically between 2000 and 5000 properties into which inflow, and where necessary, outflow is measured. Complete distribution networks are covered in such a way. Through flow monitoring of DMA’s, total demand and night flows can be recorded and interrogated either locally or remotely depending on the sophistication of logging and telemetry provided. With time, experience will enable target levels to be set to trigger activity for leakage detection or investigation of unusual flow patterns. This facility enables leakage control to be monitored using both minimum night flows and total integrated flow linked into the flow balance.
The DMA approach better targets the leakage detection effort and maximises the benefit that can be provided from specially trained detection crews using location equipment. By linking to computerised data bases, leakage and DMA performance information can be used to drive forward network rehabilitation programmes in a truly objective manner ensuring that priorities are suitably addressed.
Pressure reduction is perhaps the simplest way of reducing leakage and should always be considered as part of a proactive leakage strategy. It can be provided by simple step pressure reduction through to full variable flow where minimum network pressures can be sustained whilst meeting diurnal demand.
The use of hydraulic computer models plays an important role in leakage strategies through providing engineers with a good understanding of network performance under dynamic conditions. It has proved particularly useful in verifying DMA’s, selecting targets and identifying areas for potential pressure reduction.
To support the improved leakage identification that has results from the establishment of DMA’s and the use of advanced location equipment it is important that this is linked to speed of response in carrying out repairs. In this respect targets need to be set for repair times following leakage identification.
Consideration should also be given to introducing incentives to encourage customers to have supply pipes repaired more speedily. Historically this had proved a difficult area to work in, with most water utilities having to rely on statutory powers in legislation to enter onto private property to effect repairs to defective apparatus. This in itself was a lengthy process and fraught with difficulties, particularly where ‘shared’ services were involved.
Water utilities need to project a high profile towards leakage as part of their strategies through media campaigns and improving customer access. This latter point has been achieved by a number of utilities in Romania through the introduction of customer ‘leaklines’ whereby customers can report leakages by telephone.
PROMOTING WATER EFFICIENCY
Water utilities have had a duty to promote the efficient use of water by their customers. This has results in all utilities producing water efficiency plans in consultation with interested parties involved in conservation.
Communicating with customers
Customers awareness of the need to conserve water is monitored by market research programmes that are carried out by the water utilities. Encouragingly the research is showing an increasing awareness of the need to use water efficiently and that customers are taking increasing actions to do so. Information on ways that customers can save on the use of water are provided in many ways and through a variety of methods, these can be summarised as follows:
- Details of available information sent out with water bills
- Providing specific responses to customers’ postal or telephone phone requests
- Booklets/newsletters/ informative literature
- Visitors centres, usually located on operational sites
- Mobile visitor centres
- Television, radio and newspaper features
- Internet website
- DIY/garden centre promotions
- Information packs
- Open days
Water in the home
Efforts have focused on encouraging customers to apply water efficiency where it has a minimum impact on lifestyle.
In addition to targeted literature water utilities also make use of promotional offers on water saving devices such as showers, watering cans, water butts, rainwater diverters, water efficient washing machines and dishwashers.
Bookmarks, stickers and cards are widely used to publicise water saving tips and campaigns are used to provide specific customer advise on issues such as frost protection.
Education and schools
Education plays an integral part in any promotional campaign. Therefore an important element of water efficiency strategies is targeted towards schools and schoolchildren.
Education packs can been developed which link into the schools educational programmes. Some water utilities establish classrooms on operational sites to support the learning process for schoolchildren and teachers.
A wide selection of information is available that is geared towards schools and educational liaison between the water utilities and educational establishments are well defined.
Water utilities need to provide information for their business customers on how to use water wisely. Additionally seminars can be held to discuss ways of conserving or recycling water, these can be both general and sector specific.
Links need to be established with regional development agencies to encourage the fitting of water saving appliances in new developments. The use of new technology options such as grey water recycling units, low flush toilets and water efficient spray taps are viewed as being more likely to be accepted by customers if they are incorporated in buildings at the design stage.
As a result of the implementation of proactive water loss reduction strategies, leakage levels will reduce but it is an effort that needs to be sustained and supported if it is going to contribute to ongoing operational cost reductions.
Strategies need to be based on true facts rather than fictional information that could distort priorities for investment needs. In terms of performance reporting, this is always a challenge as there is always a need to demonstrate continuing performance against a wide spectrum of reporting indicators. Unfortunately these are not always compatible in financial terms and this can act adversely to the detriment of some activities such as leakage reduction.
There have been numerous benefits associated with targeting NRW reductions in the Romanian water sector, the main advantages of which are:
- Improved availability of water supplies
- Enhanced ability of customer affordability due to reduction in per capita consumption when tariff levels are increased
- Deferment of capital expenditure
- A better understanding of water demand profiles
- Cost effective performance of operational expenditure.
In addition to the training made available to enhance the knowledge of NRW and leakage reduction practices through the technical assistance programmes in Romania, is the ability for Water Utilities to network through nationally generated initiatives. The launch of the Leakage Challenge in 2008, under the umbrella of the Romanian Water Association, was one such initiative. It provided the opportunity for practitioners to present their strategies and practical expertise at a national level. In 2010, this was expanded to an international level. From this initiative an enthusiastic network of experts has been brought together to enable experiences and problems to be shared and discussed through vehicles such as this magazine.
My wish is for the good work to continue, as I am sure it will, due to the commitment that has been demonstrated to date. Good luck for the future.
Water Loss Detectives NO.1*2011