The money’s in the ground: engineering a solution to brownfield regeneration costs

Late last year, £80m was made available as part of the final round of funding through the Brownfield Land Release Fund 2. The BLRF is an initiative between the Department for Levelling Up, Housing and Communities and One Public Estate delivered by the Local Government Association and Cabinet Office. It aims to support the release of local authority-owned brownfield land for housing.

Initiatives such as this are an essential component in the drive to meet housing targets and back up the National Planning Policy Framework (NPPF) and Homes England’s strategic plan 2023-28.

Both initiatives prioritise brownfield development in order to better utilise existing land in built-up areas and preserve undeveloped land. For funding to be spent as judiciously as possible, understanding what is in the ground – and how it can be engineered to meet development requirements – is crucial.

Developers can be put off by the high costs associated with disposal of contaminated soils and think developing greenfield sites will save money and time, but the redevelopment of brownfield sites is vital for the UK as this protects our countryside and greenbelt from urban sprawl.

CPRE, formerly the Campaign for the Protection of Rural England, states that more than 12 million homes can be built on 23,000 sites covering 27,000 hectares of brownfield land.

We must view constraints as opportunities

By developing brownfield sites within our cities and towns we can use the infrastructure already in place to create sustainable, connected neighborhoods. Despite this potential, there is no one solution for making all sites fit for purpose and it takes professionals from various disciplines to get under the skin of a project and pinpoint which actions are required.

Henry Ford once said: “If you always do what you always did, you’ll always get what you got.” So we must view constraints as opportunities.

One of our simple priorities is being creative with our approach and developing holistic, sustainable remediation plans that are collectively designed by both ground engineers and civil engineers.

Where there’s a will, there’s a way

There are a multitude of ground-related issues that can be overcome through early-stage collaboration. Constraints imposed by contaminated land, unstable ground, challenging topography, a potential for flooding and requirements for effective infrastructure need to be confronted from the outset so that solutions can be embraced within the advancement of the masterplan.

While the master-planning process is evolving to embrace responsibilities for having a positive impact on the environment, what is in the ground and how it influences the masterplan is frequently thought of as detail that can be addressed at a later stage.

It is this lack of foresight and ensuing need for a retrofit solution that can lead to the unravelling of the masterplan and an unwelcome reversal of efficiencies and anticipated returns.

It can be of real benefit to a scheme if ground and civil engineers are given a chance to communicate their interpretation of the challenges and opportunities that each site presents, and for due recognition to be given to the importance of understanding how the ground on which the whole scheme is founded will shape its future.

Foundations in the South-west

Our work at the Glan Llyn development near Newport, south Wales, is an example of how engineering collaboration and expertise have transformed the fortunes of a flagship development. Located on the site of the former Llanwern steelworks, the 240-hectare brownfield site with permission for 4,500 homes, two schools, community facilities and a large business park, harboured a legacy of contaminated land issues.

These included the presence of heavy metals, tars, oils, ammonia, variable composition of made ground, high alkaline leachates, fused or expansive slag, soft underlying geology… the list goes on.

In 2008, an active reclamation and remediation programme began. This produced useful site-specific data, but revealed the need for costly disposal of contaminated material. With the project facing a viability problem, we were appointed to prepare a remediation strategy that would reignite the site’s development potential.

The key to the solution was identifying the way turnover and engineering of the made ground would allow a high degree of homogenisation, creating more chemically consistent material with more regular particle size, low permeability and volumetric stability, forming a platform that addresses both geotechnical and environmental issues.

The combined efforts of our geo-environmental and civil engineers to develop a strategy that would not only facilitate the reuse of approximately two million cubic metres of made ground, but do it in a way that respects the site’s complex water control and flood prevention regime, is an exceptional achievement that led to a Brownfield Briefing Award for best brownfield infrastructure project.

At a former industrial site in Gloucestershire, the site topography and relatively shallow public drainage infrastructure were driving the need for a pumped surface water drainage solution that was jeopardising the viability of a new residential scheme.

The cost and complexity of building and maintaining a pumping station with sufficient capacity to meet storm drainage criteria had been overlooked, and proposals for the regeneration of the site had forged ahead.

Costs for developing the site had already risen from initial estimates due to the belated discovery of compressible geology necessitating piled foundations. Latent difficulties with disposal of surface water had compounded the issue, leading to uncertainty about the project’s future.

It was the site’s industrial past that held the key to its future

Having invested in the preparation for a planning submission, the developer was reluctant to abandon its proposals. So it called upon our expertise to help find a solution.

It was the site’s industrial past that held the key to its future. Our engineers recognised that a clean cover could be used to prevent exposure to contaminants that originated from the site’s former use.

Introducing a clean layer of material drives site levels to a higher elevation. As a consequence, on-site drainage levels could be raised and with the addition of simple sustainable drainage techniques (SuDS), a gravity connection to the public sewer network could be implemented instead of pumping.

Earlier engagement with our engineers would have given the developer the confidence to progress their proposals without the trepidation that latent drainage-related issues could derail their plans. Fortunately, the combined efforts of our ground and civil engineers were called upon in time to restore the scheme’s viability – and ultimately re-establish a meaningful purpose for the site. 

Howel Morris is a director at Rodgers Leask