A CASE STUDY: MOLESEY WEIR REFURBISHMENT

Bolina contributed to the complex and challenging Molesey Weir Refurbishment on the Thames River.

In 2010, the UK’s Environment Agency conducted a condition survey which led to the decision to rebuild Molesey Weir, which is located immediately south of Ash Island, on the River Thames. The complex is upstream of Hampton Court Palace and helps to control water levels on the Thames between Teddington and Sunbury, marking the reconstruction out as a strategically important project.

The project involved the complete reconstruction of the existing structure, with new foundations put in place, along with an apron, stilling basin and gate supports. Over a two-year scheme of works, the existing 15 buck gates would be replaced by seven radial gates.

Furthermore, a new timber shingled canopy, supported on a steel frame, was installed to replace the old one, while the existing fish trap was replaced by a new Larinier fish pass.

In order to carry out the reconstruction, the project was awarded to Mackley Civil Engineering, a Sussex-based company who were responsible for the design, supply, delivery to site, offloading, installation and commissioning of the weir.

Working as part of Team Van Oord (TVO), Mackley carried out the reconstruction of the weir in two phases in 2013 and 2014, with no work carried out during the winter months due to the weirs needing to be fully functional when there are higher flows, in order to manage flood risk.

How Bolina Rope Safety Booms work

For the second phase of the project, starting in March 2014, Team Van Oord brought in Bolina to design, supply and deliver Rope Safety Booms (RSB1150s), complete with their associated fittings.

The Bolina Rope Safety Booms have been designed to meet a stringent set of conditions set out by the Environment Agency. They comprise of a series of guard piles spaced up to 10-metres apart with floats supporting two ropes that provide constant freeboard and air draft.

The floats have also been designed with safety mechanisms in place to allow at-risk people in the water to use them to get to safety. Furthermore, reflective panels are provided, which are visible from all upstream angles.

The internal closed cell polyurethane foam filling ensures that the float will maintain full buoyancy in an unlikely event where the outer float skin is damaged by a heavy collision, making them virtually unsinkable.

The floats can work in all conditions and follow the water level. They are ideal for flood defence and to protect vessels, structures and consequently, human lives. They are effective at stopping craft with a 40T minimum breaking load.

Bolina Rope Safety Booms save lives

There are examples of these booms saving lives, vessels and structures on the Thames ever since, and all without requiring any maintenance or repair – even after some of the worst floods on record. A remarkable achievement given that over 400 RSB1150 units have been deployed, and this is why our booms are standard throughout the whole of the River Thames.

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Read more about the details of the project on the Team Van Oord website here. Alternatively, get in touch to know more about our life-saving booms.