Havant Thicket Reservoir: Commercial Management of a Landmark UK Water Infrastructure Project

Havant Thicket Reservoir is being constructed near Rowlands Castle in Hampshire by principal contractor Future Water, under an NEC4 contract with Portsmouth Water.

The 160-hectare reservoir will be bounded by a 3km-long, 20m-high main embankment and will include a separate wetlands embankment, inlet and outlet pipelines, a visitor centre, and a network of footpaths and cycle routes.

Alongside strengthening long-term water resilience, the development will support environmental improvements through the creation of a new wetland nature reserve.

Phoenix Consulting is providing commercial support to Portsmouth Water throughout the project, helping manage the complexities associated with the delivery of this nationally significant infrastructure asset.

Phoenix Consulting delivered:

• Phoenix Consulting’s Contract and Commercial Management support includes:
• Client, contractor and third-party stakeholder management
• Change management
• Commercial forecasting
• Cost assurance
• Compensation Event assessment and management
• Coordination with external cost assurance teams and auditors

During site investigations, relict shear surfaces were identified within the ground beneath the proposed reservoir. These geological features significantly affected foundation stability and required extensive design revisions.

The resulting changes increased the scale and complexity of the works, including deeper excavations, larger embankments and changes to associated structures.

The relict shear surfaces were subsequently notified and accepted as Compensation Event CE32, representing a significant commercial change to the project.

Phoenix Consulting managed the assessment process for CE32 from acceptance through to implementation, covering a Compensation Event valued at approximately £167 million.

This involved managing a complex commercial assessment alongside Portsmouth Water, Future Water and third-party stakeholders, including the Cost Assurance team and external auditors.

Through robust change management, cost assurance and stakeholder coordination, Phoenix helped Portsmouth Water navigate a major change in project scope while maintaining clear commercial oversight and supporting informed decision-making.

Our involvement demonstrates Phoenix Consulting’s ability to provide trusted commercial expertise on complex, high-value infrastructure programmes where effective management of change, cost and risk is critical to successful delivery