Queen Elizabeth II Reservoir Tunnel Relining

The Queen Elizabeth II (QEII) Reservoir is a raw water reservoir in
South West London that is owned and operated by Thames Water.
The reservoir holds over 19 million litres of water, equating to 10% of
the raw water storage for London. Once treated, this provides clean
drinking water for millions of people across Surrey and London.

Barhale were engaged by Thames Water to complete this £11m tunnel
relining project to guarantee the integrity of the aged inlet and outlet
tunnels. The goal of the project was to strengthen the tunnels and
prevent any leakage at this crucial clean water asset.

Elan Valley Aqueduct (EVA)

After 5 years of construction, Barhale (as part of the BNM Alliance) completed work on the Elan Valley Aqueduct. The EVA is a Victorian culvert which, for the past 100 years, has carried a water supply from mid-Wales into the City of Birmingham.

The project involved the off line replacement of the existing water conduit in three locations – Bleddfa, Nantmel and Ffrydd Wood (Knighton). The new tunnel sections are 3m in diameter and each 1km or more in length.

The project commenced in 2015, and was required due to deterioration within existing sections of the EVA. The success of this project was crucial to secure a resilient water supply to Birmingham and the surrounding areas.

Chelsea to Battersea Tunnel and Gas Pipeline

Barhale carried out work on the new Chelsea to Battersea gas pipeline. As part of the ongoing work to replace and upgrade large diameter gas mains throughout central London, a new gas pipeline was required underneath the River Thames between the Royal Hospital Chelsea and Battersea Park.

The overall project was split in to two separate contracts, both of which were awarded to Barhale:

Contract 1: Construction of two shafts, connected via a new tunnel
underneath the River Thames, which would facilitate the installation
of the new 600mm diameter gas main. This contract was delivered to

Contract 2: Installation of the 600mm diameter, welded steel pipeline
through the tunnel. Including the installation of several governors
and the connection of the new pipeline into the existing network. This
contract was delivered directly to Cadent Gas Ltd.

Maida Vale Flood Alleviation Scheme

Hundreds of homes and businesses in Maida Vale have experienced dramatic flooding from heavy summer rainfall over a number of years. Thames Water and our contractor Optimise devised a solution to reduce the flooding risk for over 350 homes and businesses. The scheme includes new sewer tunnels under local, Central London roads and two new storage tanks to be constructed under local parks. It had the potential to cause widespread nuisance and disruption.

The importance of providing timely, targeted information on the project’s progress to MPs, councillors, community leaders, businesses and residents was recognised and care was taken to keep customers informed by a variety of means. As well as traditional letters and face-to-face meetings we held weekly surgeries, a web page, a quarterly magazine for residents and a text messaging service update fortnightly or when something needed to be communicated.

Westbourne Grove Flood Alleviation Scheme

Barhale were awarded the scheme by Thames Water to alleviate flooding within the Bayswater area of London.

The scheme involved the connection of the existing Victorian sewers to a new pumping station from which discharge would be carried via a new rising main to another existing brick built egg shaped sewer.

The pumping station was designed for storage of a 1 in 15 year storm. Discharge passed through a reinforced concrete valve chamber some 6m long, 3m wide and 3m deep, to a 600mm concrete outlet pipe laid in open cut trenches to the existing Victorian brick built sewer at Inverness Terrace, a narrow road with a number of Embassies to one side.

Albrighton Flood Alleviation Scheme

Barhale were awarded this £6.4 million scheme by Severn Trent Water
to upgrade the sewerage system within Albrighton, Shropshire.
The village of Albrighton had experienced substantial flooding in
recent years, due to lack of capacity in the existing sewerage system,
coupled with the volume of surface water flowing into a local brook.


Barhale offered an innovative solution to the client through carrying
out micro-tunnelling to a curved profile. This was one of the first
micro tunnels in the UK to be cut on a curve through rock and
provided a £300,000 cost saving to the client, Severn Trent.

Fisher Street – Shotcrete

Crossrail is Europe’s largest railway and infrastructure construction project, under way mainly in central London to provide a new high-frequency commuter/suburban railway service.

Barhale undertook a technically challenging project in Holborn, in central London, working for BFK under the Crossrail project.

The scheme involved constructing a 30m deep shaft solely through the use of sprayed concrete lining (SCL) technique, due to its flexibility in use. The shaft will be used for access into the underground tunnels.

Battersea Power Station – Foul Water Connection

In Battersea, the Barhale team were able to draw upon their wealth of tunnelling experience, to develop innovative solutions to mitigate un-foreseen changes to the scope of works. Their proactive approach to potential problems saved the client time and money in delivering a very tight programme.

Following the excavation of the reception cofferdam; designed to enable retrieval of the tunnelling boring machine (TBM), it was established that the existing sewer was not in the location shown on the drawings. Also, the area surrounding the sewer was overlaid by a dense zone of utility services including an Extra High Voltage (EHV) trough and large diameter portable water mains; consequently it was no longer possible to retrieve the tunnel boring machine from the cofferdam.


Wyke Gardens Dual Manhole Study

Through their expert tunnelling experience and customer care, the Barhale team at Wyke Gardens, Ealing, were able to greatly reduce long standing flooding in to the River Brent, whilst maintaining traffic flows and customer relations in a densely populated area of west London. The Wyke Gardens storm water network in west London had a history of regular flooding and discharges into the River Brent. These discharges were polluted with foul water flows from 40-50 illegal or misconnections to the storm water network.

Barhale was selected by Thames Water to:

Construct a new CSO chamber and online storage tank to reduce the discharge events and provide a new static screen to remove the solids from any overflows.

The works were based in and around the busy A406 (North Circular Road), leading to and from the Hanger Lane Gyratory System – one of the busiest junctions in London, which incorporates 10,000 vehicles an hour.

Green Lane / Great Western Road

The Green Lane (Great Western Road) Project on behalf of BFK/Crossrail involved the construction of 6 shafts (by underpinning method) and nearly 600m of pipe jacking.

The scheme was required as the existing sewer going under Network Rails Great Western Rail lines and London Underground would have clashed with the new Crossrail line. As a result, the existing sewer was abandoned and replaced with a new 1.2m pipe at a lower level. As part of the works, Barhale were responsible for the detailed design of the scheme involving consultation with Thames Water, Network Rail and London Underground. Initial works involved the location and diversion of all services at the shaft locations including Gas, Water, Electrical & Fibre Optics.