Waterford City Council has worked alongside Grontmij since 1995 to implement a water conservation and quality project. This involved undertaking mapping and establishing leakage control zones, and then identifying mains recommended for priority rehabilitation. The first two phases of mains rehabilitation in 1997 and 2000, which replaced seven kilometres of high priority main, showed pipe bursting as a very efficient and customer-sensitive method.

This work brought leakage down to an acceptable level through leak detection, repair of pipes and the replacement of poorly performing mains. Following the mapping and assessing the operation of the network, Grontmij prepared a city-wide rehabilitation report in 2003, identifying the need for further pipe replacement.

Leakage control

Control of leakage rates is currently a major priority for councils, particularly as we are experiencing increasingly dry winters and below average rainfall due to climate change. Like many councils across Europe, Waterford City has faced this issue in recent years, but also has the added challenges of rapid growth and an ageing pipe network in its existing mains distribution systems.

Many of these systems are between 40 and 100 years old and a combination of old cast iron mains, PVC and asbestos cement mains, running below streets of high footfall, traffic and population. As a result there have been problems with discoloured water from build up of matter in the pipes over the years and varying degrees of leakage. For example, in the same pipeline there may be a major leak following pipe joint failure at one point in the system, yet also pinhole leaks across hundreds of kilometres that are impossible to locate and effectively repair.

In light of the breadth of problems with the current systems, the council has now appointed Grontmij to continue with the water conservation and quality project and deliver an intensive rehabilitation programme on a larger scale than the first two phases. The consultancy is now providing pipe bursting and directional drilling to replace 19 kilometres of pipeline in the city, due for completion in February 2009.

Pipe bursting benefits

Although this method of pipe bursting has been used by consultancies in the UK for many years, the process is relatively new to Ireland for water services. Mainly used previously in the country by Dublin City Council (water mains rehabilitation) and gas contractors, the service delivered by Grontmij will be the first of its kind in Waterford and will use the latest pipe bursting technology and plastic pipe materials, coupled with accurate design and structured site management.

The pipe bursting process will be more cost-effective for the council than open trench replacement, but will also maintain the high installation quality associated with open trenching, including the ability to even out offset bends. The new plastic pipeline will offer 80 years of service life, with construction time reduced by 40 per cent, and directional drilling means 80 per cent less material is excavated.

The process is particularly suited to the inner city area of Waterford, as the work is carried out underground according to the latest technical standards by placing the new pipes inside the old, having first burst out the old line. This approach is significantly less invasive than open trenching, reducing disruption to the public by minimising road closures, site traffic and emissions.

Grontmij is also applying a customer-focused approach to the project, involving close consultation with members of the public at each stage to outline what will happen, and demonstrating how the expectations of the previous stage have been met.

With the flow

Ray Mannix, senior engineer at Waterford City Council, said: “We’re delighted to continue working with Grontmij and the council and our residents are pleased with the results so far. The non-intrusive nature of the project and the fact that it has been delivered to a high standard in a timely and cost-effective manner means we’ve been able to significantly improve our water mains system and reduce water leakage by 25 per cent in some areas already. This means we can in turn ensure we’re providing residents in the local community with the best water service possible.”

Battie White, operations director of water at Grontmij, said: “It was necessary to ensure the design and technology were cutting edge and accurate, and that there would be the minimum disruption to the local community. The project has been really successful in meeting these targets. Local residents at each stage of the process have provided positive feedback about the work undertaken on everything from the customer care and site safety, to improvement in water supplies, so we’re delighted that the project has been a success to date.

“Not only have we improved the quality of the water and replaced a significant amount of pipeline, but we have also increased revenue to the council by identifying during the course of the work a number of unmetered non-domestic premises. All non-domestic premises in Waterford City are required to install a meter to receive water services and in order to be connected to the new pipeline, these premises have had to install a meter.

"We hope to continue our strong working relationship with Waterford to ensure the mains system is working effectively and to its full potential."