MJA helped Future Water translate changes in ground conditions, design and construction methodology into an integrated commercial and delivery strategy for Havant Thicket Reservoir.

Our commercial leadership team combined issue triage, NEC change development and earthworks and civils integration as the contract value developed from approximately £150m towards £550m, reflecting expanded scope and prolongation of the whole works.

Future Water, the Mackley and Jones Bros joint venture, is delivering Havant Thicket Reservoir for Portsmouth Water. During the development of the works, changed ground conditions required a substantial rethink of the embankment and associated structures. Larger earthworks volumes, revised ground treatment and more complex civils interfaces changed the assumptions underpinning the original delivery approach.

The commercial task was to explain how these changes affected the whole project: the construction sequence, seasonal working windows, specialist supply chain, management resources and cost. Individual changes needed to be understood together to establish a credible basis for the revised works.

During May–December 2024, MJA provided contractor-side commercial leadership and an integrated team to support the joint venture. We prioritised the critical issues and interpreted the original construction methodology alongside the revised design, programme and resource requirements, helping redevelop them into a major project strategy.

CE32, the earthworks-specific compensation event, became the key to unlocking a wider series of scope changes. MJA and its team connected the construction methodology, programme and cost assessment to support those discussions, then helped carry the strategy into additional pipework and the integration of expanded Southern Water requirements.

The strategy addressed the interaction between seasonal earthworks and year-round civils construction. Ground improvement and specialist cut-off works had to be sequenced before embankment construction, while the deeper, longer culvert introduced new temporary works, dewatering and interface requirements. These dependencies affected when work could proceed and the resources needed to sustain production.

MJA connected quantities, productivity and construction resources with the wider programme and cost assessment. This distinguished additional work and increased resourcing from whole-works prolongation, including extended preliminaries for project management, site facilities and delivery support. Linking these time-related costs to the revised programme provided a clearer basis for review and negotiation.

Alongside this work, we helped develop and agree arrangements for integrating separate Tier 2 earthworks and civils organisations into a Tier 1 joint venture alternative. This connected the revised delivery structure with the scope, interfaces and commercial responsibilities of a substantially larger project.

MJA turned an earthworks-led change into a basis for wider project agreements covering reservoir works, additional pipework and expanded Southern Water requirements.

Our strategy connected the increased scope with the longer delivery period and extended preliminaries, helping establish a coherent commercial basis for a substantially larger and longer project.