Turning the wasteland into a Green Olympic park in Stratford East London
By Natasha Tourish
In East London 246ha of derelict land is being reborn as a beautiful park for the next Olympic Games and for the city’s enjoyment for decades to come.
When the International Olympic Committee (IOC) made its decision to award London the 2012 Games, the site that was earmarked for the Olympic Park was still occupied by a myriad of businesses; the full legacy of centuries of industrial activity on the site was not fully understood; and the planning process had not even started. Despite this, the organising committee for the London Games had committed to delivering what it hoped would be the world’s most sustainable sporting event.
Now, with less than a year to go, the site has been transformed. Gone is the industrial dereliction, and in its place, trees, meadow flowers and wetland plants are being planted in parallel with the construction of the iconic games venues.
Responsibility for managing the transformation of the Olympic Park site from “brown to green” has fallen to Atkins, under its enabling works contract with the Olympic Delivery Authority (ODA).
“It is easy to underplay it now, but we quickly realised that getting the land and cleaning the land were two of the biggest risks of delivering the whole 2012,” says Atkins project director Mike McNicholas.
“The ODA had to deliver both a site for the Games and a place that would be transformed into a vibrant and well-served new London community,” he adds.
Atkins was appointed as project manager for the enabling works at the start of 2006, when, as McNicholas recalls, “there was a strange state of flux. There was no planning permission for the whole park, and people were still moving out.”
“The planning strategy developed by the ODA and LDA had the mindset that we could make it work.”
According to McNicholas, the project has been “transformational” for Atkins, as well as for the Olympic Park. “As a company we have always been able to bring together diverse teams, but this was raised to new levels on London 2012 because of the requirements of the job,” he says. “We created teams of engineers who worked with ecologists, carbon experts and archaeologists, all of them pulling in the same direction.
“It’s been a real learning experience and it’s changed cultures.”
The overall vision for creating the park came from the ODA, and its project sponsor for parklands and public realm. John Hopkins is proud of the way the park’s transformation has taken place. “After all the hard work it is wonderful to see the parklands rising out of this former industrial landscape,” he says.
Remediation
A key element of London’s commitment to make the 2012 Games the most sustainable ever held was the choice of the site for the main Olympic Park: a 246ha piece of brownfield land in east London bounded by railway lines, crisscrossed by neglected waterways and boasting a history of industrial pollution dating back two centuries. An important remit of the Games is to transform this landscape into an urban park that will be enjoyed for many years to come.
At the start of Atkins’ enabling works contract, many businesses were still occupying the site, but as each one moved out, teams went in to carry out full investigation of the ground below, eventually doing over 3,000 intrusive site investigations (including boreholes, trial pits and window samples) to add to information already known about the historic uses of the site. These include a waste tip, fridge mountain, chemical works, glue factory, landfill site and a bus depot – all adding their own particular type of contaminant to either the underlying soil or the groundwater.
Each borehole survey helped Atkins establish exactly what was in the ground, and fed into the design of the remediation strategy.
“We had to identify how we could start construction in line with the needs of the programme – from a stakeholder management perspective, a technical perspective, hitting the budget together with the ODA, and developing the design management strategy.”
Mike McNicholas said that very little of the Olympic Park was fully designed at the start of the project. To enable fast decision- making and constant communication with the client, local planning authorities, regulators and contractors, Atkins pulled in experts from throughout the UK and co-located them in a single project office in London, which had its own culture and behaviours. And at the top were managers brought in for their leadership capability, rather than their technical knowledge.
Rivers
A major feature of the Olympic Park will be the waterways that snake through the site. The main stadium is almost surrounded by water, including the River Lea, which runs through the entire park from northwest to south- east. The southern part of the site has always been the most urbanised, and will remain so in legacy.
The masterplan for the Olympic Park was to retain 2.6km of soft banks in the area known as the North Park and to make this a far more natural landscape than the south.
“Initially the banks were going to have high, steep slopes with a path along the top, but in 2008 the masterplan changed,” explains Atkins principal engineer Mike Vaughan. “Getting the river geometry just right was a delicate balancing act. If they were too steep the banks would need expensive artificial reinforcement, but too shallow and they would start to eat into valuable space on the site.”
He adds: “Working with the landscape architects we looked at how they could incorporate the river more and open up the corridor to make it a feature and draw people towards it. By dropping the slopes we’ve brought the river into the park and made it much more accessible. People can get close to the river and see what’s going on there.”
In order to turn the waterways into a major feature of the park, the first task was to understand exactly how they behaved and linked together. Flows and velocities were measured at different locations, and the data used to construct a detailed hydraulic model to predict flood risk.
Planting
Planting is a major feature of the new landscape that is being created. As well as contributing to an attractive environment during the Games, the plants will help give stability to the river banks and create vital wetland habitats. There are many native wetland species that should be suitable for this environment, but the Lower Lea has some characteristics that made it challenging to design the planting regime, including the 400mm fluctuation in water level. Any plants introduced on the riverbank have to be able to cope with these major fluctuations.
In addition, the Lea is a heavily silted river, so the plants also have to be tough enough to withstand layers of silt being deposited on the bank.
To find the right plants, Atkins instigated a 12-month planting trial in 2008, using a variety of plants native to the Lea and Thames estuary, and different planting methods, including plug (or cell) planting, where the plants are individually plugged into the soil; bare root planting; planting in five litre containers; and coir pallets, in which the young plants are delivered to site already planted in coir mats.
The trial involved a 50m stretch of riverbank in wetland area of the North Park and identified which species coped best with the tough conditions, and since 2009 specialist company Salix has been growing a range of native wetland plants that are currently being planted in the site. They consist mainly of emergent grasses and sedges, as well as yellow irises and purple loosestrife, which should be in flower during the Games.
After a year of growth in the nursery, the wetland plants were installed under the supervision of Bam Nuttall, who has a contract to manage the landscape works. They arrived on 300 lorries, with each of the 1,000 pallets and rolls tagged to indicate exactly where it fits on the riverbank, enabling them to be pieced together like a massive jigsaw puzzle. With the ground at the river edge being soft and wet, the contractors are using a specially adapted pontoon to give them access to the banks for planting.
Legacy
It is widely believed that London won the right to host the 2012 Olympics because of its commitment to use the event to create a lasting legacy. The organizers boast that 75% of all the money spent on the event goes on something that will remain long after the Games are over. Crucial to that is the creation of one of Europe’s largest “urban parks” around the sports venues.
ODA project sponsor for parklands and public realm John Hopkins says: “After the Games we will spend a year transforming the site from a secure compound into an open, inviting parkland. The park will transform the area from the urban Hackney Marshes to the rural Lea Valley.”
The new park has two distinctly different parts. The South Park will be very colourful and decorative and more urban, with lawns and mature trees, while the North Park is more natural, and restored to how it might have looked before the industry came along.
The landscape designer has produced some very precise landforms with the intention that it feels like you are out in the countryside with the velodrome and basketball venue almost hidden in between.
New wetland habitats will be created along the section of River Lea that runs through the North Park, together with an area of wet woodland – a rare British habitat with a dark, hostile feel that supports trees like willow, alder and black poplar. This area needs to be kept damp, so Atkins has designed a system that will allow water to overtop a section of riverbank once every four weeks.
During the Games a pedestrian link will pass close to the wet woodland to give access to one of the temporary bridges into the stadium, but in legacy this will be removed, so the woodland can be allowed to grow further.
“For the next couple of years the park will be carefully managed and manicured, but after the Games are over, one of the most exciting aspects will be allowing and watching the woodlands materialise,” says Vaughan.
Other new habitats include three frog ponds fed by drainage from the venue concourses.
To ensure all the new habitats thrive once the Games are over, they have been designed to require minimum intervention.
“The way we’ve been tackling the design with sustainability and bio-engineering techniques means we have designed out the need for maintenance in the future,” explains Vaughan.
“It’s a natural river – let it do what it does.”
For ODA chairman John Armitt, the park is crucial to the success of the Games and their long-term impact.
“The parklands will be the centerpiece of the Olympic Park during the Games, and are at the heart of the long-term transformation of this part of east London,” he added.
