Case Studies

Pressure management of potable water distribution systems is now undergoing an international renaissance, as Utilities begin to realise the many benefits that it can bring. Thirty years ago, research in Japan and the United Kingdom identified that the average relationship between pressure and flow rates of leaks in distribution systems was approximately linear, rather than a square root relationship.

This paper aims to demonstrate that through the practical application of advanced pressure control methodologies, a significant improvement in the efficiency of distribution systems is feasible and can also provide an example to encourage other utilities to improve their performance.

South Africa boasts several of the largest and most successful advanced pressure management installations in the world, some of which have received both national and international recognition.

During their international water loss studies, the authors have worked in or with countries where the recommended guidelines or targets set by national organisations for water losses can have unforeseen, and presumably unintended, consequences.

This paper outlines the development and evaluation of two small residential District Metered Areas (DMAs) within the East Bay Municipal Utility District service area in northern California. The two areas have significantly different non-revenue water characteristics. The District evaluated the system usage through analysis of hourly SCADA, reservoir level data, and customer consumption using Automatic Meter Reading (AMR) systems recording on hourly intervals. This data was recorded, validated, and analyzed to better define the non-revenue water and the variation of apparent and real losses in both systems.

The Emfuleni Local Municipality is situated in southern Gauteng and supplies water to a population of 757,555 with a daily consumption of approximately 200Ml / day. The area is characterised by high water losses and limited cost recovery.

The City of Tshwane has undertaken various initiatives over the past 10 years to quantify and reduce its non-revenue water. The City of Tshwane has an advanced Management Information System in place which is used for, amongst other things, to identify areas with high non-revenue water levels, graphically display the demand per stand and to graphically display where un-metered stands are located.

Khayelitsha is one of the largest townships in South Africa and is located approximately 20 km from Cape Town on the Cape Flats (a large flat sandy area at or near sea level). There are approximately 43,000 serviced sites with both internal water supply and water borne sewage while there are a further 27 000 low-cost housing units which are supplied from communal standpipes supporting a population of approximately 450,000.

The Khayelitsha Pressure Management Project has been well documented and widely publicised since it was commissioned towards the end of 2001. The project has received numerous national and international awards for technical excellence as well as for environmental awareness and community involvement. The initial water saved by the project was estimated to be in the order of 9 million m3 /yr representing approximately 40% of the original 22 million m3 /yr supplied to the area.

Khayelitsha is one of the largest townships in South Africa with a population of approximately 450,000. It is located approximately 20 km from Cape Town on the Cape Flats (a large flat sandy area at or near sea level). There are approximately 43,000 serviced sites with both internal water supply and water borne sewage while a further 27,000 lowcost housing units are supplied from communal standpipes

The City of Toronto water distribution system is comprised of over 5,500 km of watermain and services over 464,000 connections. Traditionally, water loss levels have been tracked via a rudimentary Unaccounted-for Water (UFW) analysis which compares the volume of water supplied into the distribution system to the volume of water sold to customers. Historically, this value has varied between 10 to 15% - a figure believed to be reasonably good.

Gauteng province is the industrial heartland of South Africa and is one of the few large urbanised areas in the world that is not located adjacent to a major source of water. The demand for water in Gauteng outstripped the local resource of the Vaal River many years ago with the result that the area relies heavily on large water schemes which transfer water from adjacent river basins into the Vaal River basin. The water transfer schemes associated with the Vaal River basin are large by any international standards and the water resource system is one of the most complex and integrated anywhere in the world.

Skopje conference 2006 : Water loss management, telemetry and SCADA systems in water distribution systems

Water distribution system is located in the northern part of Croatia, 30 km east from its capitol Zagreb (South-east Europe) and covers approx. 300 km of pipelines with 5500 service connections (visible towns on the map; Ivanic Grad, Klostar Ivanic, Kriz and Novoselec with smaller villages in Figure 1).

Many water distribution systems in South Africa are deteriorating due to many years of neglect, resulting in a serious maintenance backlog. Aiming to find a solution to this, one of the largest advanced pressure management projects in the world was undertaken, which successfully tackled water losses and improved network management.