Vyrnwy Aqueduct Modernisation Programme reaches major milestone to benefit over a million customers in the North West

United Utilities has reached the momentous halfway point in its Vyrnwy Aqueduct Modernisation Programme (VAMP), upgrading 139km of pipes that serve water to a million customers across Cheshire and Merseyside.

The Vyrnwy Aqueduct consists of three parallel pipes that run from Lake Vyrnwy through to Merseyside, and account for an impressive 12% of our raw water through the North West. The eight-year project to upgrade and reinvest in the water network spans from our Water Treatment at Oswestry, through to Prescot and cleaning a total of 139km of pipework, and the first pipe was installed in 1892 to help deliver clean drinking water to customers and communities across Cheshire, Merseyside and the wider region, transporting up to 210 million litres of water a day to just under a million customers.

Two of those pipes undergoing modernisation are cast iron, and will be slip lined with newer pipes constructed of polyethylene. A modern material compared to the original cast iron and steel, the polyethylene liner means the water passing through the pipes is wholesome and of high quality, meeting United Utilities’ commitment to drinking water in the North West meeting the highest standards. The liner will also eliminate any cast iron deposits, which mineralise the water and can cause a slight (non-harmful) discolouration when coming through taps.

But new technology and industry leading innovation continues to offer better, more qualitive solutions to ensuring the pipe upgrades are resilient enough for the next one hundred years and beyond. In 2023, the water company set contractors AVOVE and OCU further water saving targets while also reducing the program’s carbon footprint. The teams also had to deliver efficient engineering solutions to complex sections of the upgrades (such as complex bends and heavy urban areas). Part of this solution is the ‘pipe pusher’, a clever piece of technology that can push up to 2km of pipelining through the network, well over double the traditional 900m. This not only creates a smaller number of excavations but reduces disruption and impact on the community and environment.

United Utilities was also the first to use a technique on its third pipe upgrade called air pigging on larger pipes at a 42” diameter and 2.6km in length. The technique uses steel bitumen lined pipe to remove the iron and manganese deposits that have built over the last 100 years from when it was first installed, ultimately improving the final product in customer taps with a holistic approach to water quality first – a business priority and now championed as best practice within the sector.

The process of air pigging forces the lining through the pipe using compressed air to move it. This is then repeated using pigs with different scouring covers, starting with a rough one to begin, moving to a gentler one at the end, very similar to the scouring sponges used to wash the dishes. Essentially, this produces a glove-like-fit for the liners and resilience within the pipe framework. Other advantages of this technique is time; it’s quicker, can clean longer distances and so far looks to be more effective than traditional jetting while using considerably less water.

Due to the scale of the project, and so we maintain the water supply to our customers and minimise disruption, United Utilities has chosen a staggered approach to construction on each line of pipework, with both methods involving excavation along the pipes at 800m intervals future proofing the pipework by prioritising quality and excellence.

Will Eyre, Regional Delivery Manager for the Vyrnwy Aqueduct Modernisation Programme said: “We’re really pleased with progress on this extensive and innovative project, which spans such a huge part of our region. We have trialled and tested new technology, worked with local authorities and stakeholders to manage timelines, and have engaged with landowners and occupiers in more than 70 areas of privately owned land. We continue to engage with the local community from the full stretch between Malpas and Prescot, and we’re pleased to say that overall, they have been very welcoming and understand why it needs to happen.

“We have only achieved this by working closely with our construction partners at AVOVE and OCU who have worked collaboratively to achieve these goals. What we have achieved just in the first three years of this programme is due to the incredible effort from all of the team. We are continuously learning and adopting new approaches as we progress.

“United Utilities has a dedicated website where the status of the project, images of its progress and the benefits (both short and long term) are clear to see and can be accessed by the public at any time.

“As the project accelerates into its final three-year phase, we would like to thank our customers, constituents and communities across Cheshire and Merseyside as we work towards a stronger, greener and healthier North West.”

For more information and to check the progress of the Vyrnwy project, click here.