How digital design development is helping to progress the Grand Union Canal Transfer scheme

Using digital tools to de‑risk consent on the Grand Union Canal Transfer  

The Grand Union Canal Transfer is a nationally significant water resilience scheme that will transfer highly treated recycled water from the Midlands to the southeast of England. Affinity Water, Severn Trent Water and the Canal & River Trust appointed Mott MacDonald as planning lead in 2023 to take the scheme through the Development Consent Order (DCO) process.

The Grand Union Canal Transfer is one of a new generation of strategic water resource schemes being developed to address long-term water stress across England. However, instead of using all new pipelines, the scheme will use a 131km length of England’s historic canal network for the water transfer. Spanning a total length of around 161km, the scheme will move water from areas of surplus in Severn Trent Water’s supply area to areas of deficit within Affinity Water’s region.

The planned scheme is being designed to transfer up to 115M litres of treated water a day from Severn Trent Water’s Minworth Advanced Water Treatment Plant in Birmingham southwards through the Coventry, Oxford and Grand Union Canals operated by the Canal & River Trust. It will deliver the water into Affinity Water’s service reservoir at Chaul End near Luton to undergo further treatment before it is supplied to customers.

The scheme was first identified by Affinity Water’s Water Resources Management Plan (WRMP) as a preferred option to address a forecast long‑term supply deficit driven by population growth, climate change and environmental pressures. It also features in Severn Trent Water's WRMP and the Water Resources South East regional plan. Water companies in England and Wales are required to produce a WRMP every five years, setting out how they will secure reliable water supplies over the coming decades. The Grand Union Canal Transfer responds directly to this requirement by providing a sustainable, long‑term transfer solution that is being designed to protect the environment, support regional resilience and ensure customers continue to receive affordable, reliable supplies as pressures on water resources increase.

Scale and timing challenges

The technical solution is only part of the story. The scheme is also among a new generation of strategic water resource projects being developed through the Development Consent Order (DCO) process – a planning route that is still relatively new to the water sector.

“The scheme’s scale alone makes it nationally significant,” explains Mott MacDonald technical director for town planning Sarah Henderson. “But its timing is also particularly important.”

While schemes that come under the government’s Nationally Significant Infrastructure Project designation, such as those in the transport and energy sectors, have long been delivered through the DCO regime, that has not been the case in the water industry. Taking major schemes through this planning route calls for deep understanding of the process, as well as domain expertise of the sector too. According to Sarah, the need for water domain expertise combined with DCO experience led Mott MacDonald to bring Adams Hendry Consulting on board as a sub-consultant, due to its established water sector consenting knowledge that complemented Mott MacDonald’s DCO experience in other sectors.

Sarah adds: “Outside of the use of a DCO by Thames Water for the Tideway Tunnel, and Anglian Water for the Cambridge Waste Water Treatment Plant relocation, these water transfer schemes simply haven’t been built before. That means many water companies have just not had the opportunity to gain major consenting experience.”

This context shaped the scheme from the outset. The challenge was not only to develop a complex, linear infrastructure scheme, but to support it through a consenting process that was unfamiliar in scale, structure and scrutiny for the water industry.

From planning outputs to a guiding role

Mott MacDonald’s appointment as DCO planning lead placed the team at the centre of that challenge. Formally, the role involves coordinating and producing the documents required for the DCO application. In practice, it has required much more than document production. Mott MacDonald has played a key role in aligning the partners on how to create the deliverables and associated governance for the DCO and developing the streamlined process behind that.

The scheme has three client partners. Each brings different responsibilities, funding arrangements and organisational cultures. None had recently promoted a nationally significant water scheme through the DCO regime. This meant that consenting could not be treated as a downstream activity. It needed to shape design development, governance and decision‑making from the start.

Sarah explains that Mott MacDonald took on the role of a “guiding mind” for the scheme. “The team provided a consistent DCO lens across engineering, environmental assessment and stakeholder engagement,” she explains. “This helped the partners understand what certainty was required for consent, where flexibility could be retained and how design development requires to be recorded to stand up to future examination.”

Digital foundation for consent

One of the defining features of the scheme has been the early and sustained use of digital tools to support DCO preparation. During the initial stages, the team identified a significant opportunity to increase efficiency and manage complexity by creating a common data environment that would support all organisations and disciplines.

Mott MacDonald introduced its Geospatial Digital Tool as the central platform for coordinating design development through identification of environmental constraints and stakeholder and land information to address this. The tool brought spatial data into a single shared environment that could be accessed by all partners.

Rather than being treated as a specialist system, Mott MacDonald’s Geospatial Digital Tool became embedded in day‑to‑day working. It is now used in meetings, workshops and design reviews to test options, understand constraints and support collective decision‑making.

“People often talk about a single source of truth,” Sarah reflects. “On this scheme, it genuinely is. Everybody uses it and refers to it.”

For the DCO process, this consistency is critical. “Using the digital tool has reduced duplication, improved confidence in the evidence base and allowed complex discussions to be grounded in the same information,” she says.

Designing with consent in mind

One of the most difficult questions for DCOs is how much design detail is enough. Too little detail creates uncertainty at the examination stage but adding too much ahead of the DCO application removes flexibility during the procurement and construction phases.

Mott MacDonald’s role has been to help manage this balance in a structured way. The team designed and led a series of design fix workshops, working systematically along the route from north to south.

“It was about putting a pin in the ground,” Sarah explains. “So the environmental impact assessment team could start producing the preliminary reports that are vital for both the public consultation phases of the scheme, as well as the DCO application itself.”

These workshops captured agreed design positions that were suitable for consultation and environmental assessment. They also recorded what was not yet fixed. Gaps in information were logged, tracked and revisited. This ensured issues were visible rather than lost as the scheme evolved.

For a long, linear scheme with multiple partners, this audit trail is essential. It now underpins the emerging environmental statement and will provide critical evidence during the DCO examination.

Managing scale, geography and scrutiny

The Grand Union Canal Transfer spans 10 local planning authority areas and interfaces with 53 parish councils. It also engages a wide range of statutory stakeholders. “This level of geographic spread is more common in linear transport schemes than water projects,” adds Sarah.

Maintaining consistency across such a footprint has been a core focus. Use of the Geospatial Digital Tool has supported this by ensuring that discussions about access, environment and construction are grounded in the same spatial evidence.

For stakeholders unfamiliar with water DCOs, this clarity has been particularly important. It has helped explain complex proposals clearly and demonstrate that decisions are being made in a transparent and structured way.

The Geospatial Digital Tool will continue to play a central role as the scheme moves towards examination and through the process too.

Putting plans to the consultation test

The scheme has now completed two stages of public consultation. The first, in autumn 2024, explored a wide range of options. The second, which concluded in spring 2026, focused on more defined proposals.

Mott MacDonald produced scheme development options reports for both stages. These documents explained how the scheme had evolved and why options were selected or discounted. They provided a clear narrative that could be tested through consultation.

The team also attended consultation events along the route. This allowed concerns to be heard directly and fed back into design development.

“The consultation feedback for the second stage has been constructive and informed,” Sarah notes. From her experience of the consultation process on other DCO applications, Sarah says that the reduced number of responses from the first consultation is a positive sign. “It suggests that stakeholder issues have been identified and addressed early,” she says.

With the second consultation now complete, the project team is reviewing responses and considering how they will inform the next stage of design.

Preparing for application

The focus for the Mott MacDonald team now is to progress the design development and prepare the DCO planning documents.

“The DCO application is expected to be submitted in 2027,” says Sarah. “The Geospatial Digital Tool will continue to play a central role as the scheme moves towards examination and through the process too.”

The platform will support the management of design change, the tracking of commitments and the ability to respond clearly and consistently to examination questions. “For a project of this scale, that digital audit trail will be critical,” adds Sarah.

Getting the scheme through the DCO process successfully in 2027 is critical to the ambition of Affinity Water, Severn Trent Water and the Canal & River Trust to have the scheme operational in the early 2030s.

While the scheme will improve water supply certainty in the southeast, Sarah believes that its significance extends beyond this scheme alone. “It provides a practical example of how digital tools can support consenting in sectors that are new to the DCO regime,” she explains.

“That consistent approach to design development becomes the baseline. That’s what we can lift and shift onto other projects.”

For the water industry, as well as other sectors facing increasingly complex consenting challenges, the scheme shows how early investment in digital platforms, clear governance and a strong guiding role can drive efficiency, consistency and confidence through the planning process.