05 Jan, 2022 By
Completion of a 20 year PPP project in the Norfolk Broads has improved flood resilience of a 240km network of waterways and established some valuable best practice for the wider industry.
Local materials sourcing, circular economies and nature-based solutions are concepts we are now familiar with but 20 years ago, they were less recognised. Yet a Norfolk Broads flood protection project which began in 2001 has pioneered these ideas and delivered cost, carbon and programme savings, as well as flood resilience.
When it started two decades ago, the £150M Broadland Flood Alleviation Project was one of two Department for Environment, Food & Rural Affairs (Defra) pilot projects to use a public private partnership (PPP) for delivering flood defence improvements. The other – the Pevensey Bay Sea Defence scheme – has another four years to run but is significantly smaller than the Broadland project that sought to improve flood defences over a 240km network of waterways.
The Broadland programme’s focus was to improve and maintain the flood defences along the tidal reaches of the Rivers Yare, Bure, Waveney and their tributaries in Norfolk and North Suffolk. 
Jacobs and Bam Nuttall formed a joint venture called Broadland Environmental Services Limited (BESL) to deliver the PPP project for Defra and the Environment Agency.
The project was an essential mechanism to get the flood defences in the area up to a serviceable standard so they could cope with day to day flood risks, as well as those brought to the low lying region by climate change.
“In 2001, there had been no capital expenditure on the Broads for 25 to 30 years,” says Jacobs project manager and BESL technical manager Kevin Marsh. “The approach was very much wait until it breaks, then fix it. Spending was just not keeping pace with deterioration and repairs were carried out piecemeal.
“At both Broadland and Pevensey, Defra wanted a longer term asset management approach.”
It is clear that Marsh believes the project delivered on its aims but a lot was learned over the project’s 20 year lifespan.
As well as covering significant lengths of river, the Broadland project also includes 30,000ha of land and protects 1,700 properties. The team faced some hard choices about what to do, where and in what order.
The site area was divided into 40 “flood compartments” with between 2km and 20km of river within each. Each of the 40 compartments received large volumes of capital expenditure in the first 12 to 15 years of the project. From year 13 onwards, the emphasis switched to maintaining the renewed assets, which Bam Nuttall and BESL project manager Jason Parker predicts have at least seven to 10 years of residual life at the end of the project.
Marsh explains that the emphasis was not on hard engineering but on realigning embankments, building reedbeds and working with nature rather than always trying to control it. 
Spending was just not keeping pace with deterioration and repairs were carried out piecemeal
“In some areas we set back the riverbank by up to 30m and allowed the river to erode naturally,” he explains. This set back process involved removing existing sheet pile flood defences rather than installing new ones and creating places where the Broads Authority could place dredged material – previously a contentious issue, locally. 
The hard flood defence materials that were removed were recycled on other parts of the project. A total of 7.5 linear kilometres of steel sheet and timber piles – almost a quarter of those removed and replaced by reedbed – were reused elsewhere in the project area.
“We had our own recycling yard and were able to tailor the design for upcoming work based on the materials we have available there or that we could source locally,” explains Marsh. “I think less than 5% of the materials we used were imported to the area. We were delivering on the carbon agenda even before that became something for projects to focus on.”
The longer term approach at Broadland also allowed BESL to trial different techniques and gain greater understanding of what worked and what was unsuccessful, especially when it came to erosion control. Reedbeds proved to be the best solution for this, and had the added benefit of creating a more natural look.

A flood event in 2013 proved the worth of the project
Although the aims of the project may sound like the perfect fit with the natural environment the team was working in, many local people were not initially convinced by the approach. According to Marsh, the first few years on site involved a huge focus on stakeholder engagement and on developing strategic objectives that aimed to deliver more than just flood defences for the communities around the Broads (see box).
The real proof for those unsure of the approach came in 2013 when the east coast of England was hit by the biggest surge tide since 1912 – larger even than during the now infamous  great storm of 1953. 
“We had an overtopping [of the defences] event in 2013 but the flood water quickly drained,” says Parker. “People saw the flooding of the Somerset Levels at the same time and that water stayed for weeks and weeks and they realised that it could have been the same on the Broads too.”
At peak, during the capital expenditure phase, 100 people were working on the project and there was a distinct cycle of earthworks in the summer and piling in the winter with the aim of delivering four to five capital projects at any one time. 
We were delivering on the carbon agenda before that became something for projects to focus on
During the maintenance phase, which involved day to day tasks like mowing grass and topping up embankments, 10 to 15 people were working on the project.
For BESL commercial manager Dave Thompson, it is the people who delivered the work that really made it such a success. 
“I have never seen the level of teamwork that was delivered here before,” he says. 
“There was a real spirit of mutual trust and cooperation between the firms involved in the project.”
Thompson is also proud of the financial metrics of the project. 
“We had a contract that ran to over 800 pages, which shows the complexity of the set up,” he explains to underline the potential risk of overspend.
“At the outset the cost was £106M but with additional work it was valued at £163M but we brought the work in for £150M.”
While the PPP project itself has now ended, BESL has been contracted to undertake a further two years of maintenance work in the project area. 
The Environment Agency is already looking ahead to what it needs when the current maintenance period comes to an end in 2023. 
Environment Agency project manager Paul Mitchelmore is very happy with the results of the PPP approach: “This project has given us a unique opportunity to extend the life of these flood defences and help to preserve the special qualities of the Broads. 
“We now have a more sustainable flood defence system which will reduce the burden for its upkeep on future generations.”
Like what you’ve read? To receive New Civil Engineer’s daily and weekly newsletters click here.
Tagged with:
or a new account to join the discussion.
Jones Bros
Jones Bros