Utility Week Awards winner case study: Anglian Water’s Grafham Resilience Scheme

Anglian Water won the 2017 Utility Week Capital Project Management Award for its Grafham Resilience Scheme. Utility Week takes a look at this ground-breaking project and the criteria Anglian met to win the award.

The £28 million Grafham Resilience Scheme is an innovative program from Anglian Water that reverses water flow in the event of an emergency.

75 per cent of the 829,000 people in the Huntingdon, Northampton and Bedford areas served by Grafham Water Treatment Works would be affected in the event of an outage in its network.

So to combat the risk, Anglian wanted to install a major water main between Hannington Reservoir and Grafham. But it transpired that route would have presented significant hurdles for the company, with river crossings and urban areas among the obstacles in the way. The resilience scheme at Grafham has achieved the same outcome as the original plan would have, but at half the cost. It has also cut embodied carbon by 61 per cent (26,845 tonnes), compared to what would have been used by the Hannington water main.

What was the scale of the project?

In order to deal with these challenges, Anglian had to come up with a radical approach. Through ground-breaking adjustments, monitoring the pipe network and new ways of working, the team successfully allowed the reversal of flow through one of the existing water mains.

During the project the team made 56 connections to live water mains without any interruption to customers. A typical regional operations team would undertake just 26 such connections annually.

The largest such connection had the potential to affect a staggering 400,000 customers, but through efficient execution, no customers were affected. Over the course of the project, a total of 6,000 cubic metres of concrete was used to construct the reservoir tank, making it the largest pre-cast storage reservoir in Europe.

The new storage reservoir holds 40 million litres of treated drinking water, which is equivalent to 16 Olympic-sized swimming pools. If a kitchen tap was turned on in one corner it would take five years to drain the reservoir.

What was the target group?

Anglian serves some of the fastest growing parts of the UK, and with significant population growth predicted over the next 25 years the company needs ever resilient systems to meet the challenges of this growth, as well as simultaneously protect the environment.

It is forecast that more than a quarter of a million new homes will have been built by 2036 and more than 380,000 jobs are expected to be created across Cambridgeshire, Bedfordshire and Northamptonshire, the area Grafham serves. Yet with only half the national average rainfall each year, the east of England is the driest region in the UK.

The resilience scheme at Grafham Water Treatment Works has significantly increased the security of water supplies to customers in the west of their region.

Why this approach?

The team cites their ground-breaking 2015 trial, challenging the status quo and collaboration across various teams as the reasons behind the outcome being possible. As with any infrastructure scheme, Anglian needed to work to halve embodied carbon before seeking agreement to proceed.

What were the KPIs?

As with all infrastructure schemes KPIs included halving embodied carbon and construction time and avoiding all accidents. The Grafham scheme was no different to any other and achieved all of these, with no health and safety incidents throughout the entire project.

The initial Hannington design was forecast to cost £60 million and use 43,648 tonnes of carbon while the final scheme cost £28 million and used 16,803 tonnes of carbon, saving a total of 26,845 tonnes of CO2 (62 per cent).

How was creativity demonstrated?

Collaboration enabled the project team to rethink the original solution. Networks manager Karl Porter led the enabling project, which challenged the status quo from the outset as it was a networks expert providing a fresh perspective to managing a supply scheme.

Karl brought also bought infrastructure modeller Kirsty Jones out into the field to get a better understanding of the equipment operations and how to use those to update the hydraulic model.

Working on site at night, Kirsty was able to take first-hand notes of the system operations. That night testing and data recording enabled the teams to build confidence in the variable speed pumps (VSP) operations.

Eventually they were able to operate the VSPs at a level outside the normal design specification and still achieve controlled, stable operations.

how did the project fit with the company’s broader objectives?

The reduced carbon and cost combined allowed £40million to be reinvested to fund more renewables, generating even further efficiencies for the business.

Who was involved?

This scheme demonstrated collaboration across water networks, water supply and asset management.

The project was delivered by Anglian Water’s @One Alliance, with delivery partners Mott MacDonald and JN Bentley (now Mott MacDonald Bentley, MMB).

In addition to the Anglian Water asset delivery team, the other @One Alliance partners were Balfour Beatty, Barhale, Mott MacDonald Bentley (MMB), Stantec, Skanska and Sweco.

Were there any hurdles along the way?

In addition to having to achieve the 50 per cent carbon-saving KPI, the flow reversal trial itself was fraught with engineering challenges that the teams overcame, while maintaining supplies to customers throughout.

A total of 200 man-hours were spent modelling the variable speed pumps and equipment vital to the success of the 2015 flow reversal trial.

The scheme also saw partners JN Bentley carry out one of the largest line stops in its engineering history to enable them to weld onto a bitumen pipe without having to drain down the sizeable main.

The approach of reusing existing equipment enabled a cheaper, lower carbon solution to be proposed. The scheme also won the Carbon Reduction Project of the Year award at the rigorously-judged British Construction Industry Awards.

What was the cost of the project?

In total the project cost £28 million and took a quarter of a million man-hours to complete the construction of the new reservoir and pumping station and to carry out the numerous network adjustments.

What the judges said

The judges praised the clarity of the entry, saying it was well explained and well presented.

They said it was “a fantastic example project for the industry”, adding: “You can feel the pride in this project.”

Comment

The Utility Week Awards are held in association with CGI and Capgemini.

The 2018 Utility Week Awards will be opening soon. Sponsorship opportunities are available – contact Utility Week business development manager Ben Hammond on benhammond@fav-house.com or 01342 332116 for more information.