HS2 N1-N2 Bromford Tunnel West Portal & Washwood Heath Retained Cut Dewatering

Due for completion in 2033, the HS2 (High Speed 2) rail network is among the most significant building projects taking place in the UK. In 2022, WJ was contracted by the Balfour Beatty and Vinci joint venture to provide hydrogeology solutions towards the construction of an intermediate ventilation shaft at Bromford Tunnel, near Birmingham.

Project overview

The HS2 rail network is one of the UK’s most ambitious infrastructure projects, designed to revolutionise high-speed rail travel and improve connectivity. As part of this initiative, the Bromford Tunnel West Portal (BTWP) and Washwood Heath Retained Cut (WWHRC) required an advanced dewatering and water treatment system to facilitate construction. The 750-meter-long western portal at Washwood Heath serves as a critical breakthrough point for tunnel boring machines (TBMs) excavating the 5.6 km twin-bore Bromford Tunnel.

Client

Balfour Beatty VINCI (BBV)

Project owner

HS2 Ltd

WJ was engaged to provide groundwater control and contamination treatment solutions, ensuring stable excavation conditions and environmental compliance.

Project Scope and Challenges

The construction of the 22-meter-deep portal structure and associated cuttings required precise groundwater management. The site presented unique challenges, including:

High groundwater levels that needed to be controlled for safe excavation.
Historic hydrocarbon contamination requiring specialised treatment before discharge.
Real-time compliance monitoring to meet environmental regulations.

To address these challenges, WJ conducted a detailed pumping test to gather essential hydrogeological data, optimising the dewatering and treatment system design before installation.

WJ’s Innovative Approach

WJ’s solutions for this project included:

Deepwell Dewatering System: A robust dewatering setup ensured stable groundwater levels during excavation and construction.
Activated Carbon Water Treatment: This system effectively removed hydrocarbon contaminants, allowing for safe discharge while adhering to strict environmental standards.
Real-Time Monitoring & Compliance Testing: Groundwater levels and water quality data were continuously tracked via WJ’s cloud-based monitoring portal, providing engineers with up-to-date insights. Weekly compliance sampling ensured full adherence to regulatory requirements.

A Key Contribution to HS2’s Success

WJ’s expertise played a critical role in keeping the project on schedule and within environmental compliance. By integrating dewatering and water treatment technologies, we provided a seamless solution that met the project’s engineering and sustainability objectives.

The WJ Difference

At WJ, we go beyond water management—we provide innovative, data-driven solutions that enable major infrastructure projects to progress efficiently and sustainably. The HS2 Bromford Tunnel West Portal project showcases our ability to deliver integrated dewatering and contamination treatment systems in complex environments.

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