The existing steel sheet pile flood defence wall runs along the River Haven, Boston and dates
from the 1930’s. As part of the Environment Agency’s progressive Flood Defence Scheme and
Maintenance Works they determined the wall needed replacing. Interserve were contracted
to install a new 240m long sheet piled wall in front of the existing. The new sheet piled wall
design, as well as requiring the installation of new sheet piles, required anchors to be
installed every 1.4 metres, extending 19 metres into the ground at a 30o angle. A new
capping beam installation was of steel construction. Interserve used innovative techniques to
reduce the risks of pouring concrete in an estuarine environment and to reduce the extent of
New Flood Wall Installation
In 2013, Boston experienced the worst floods in its history. The existing apron was the issue
and was undermined by scour and free flowing water over time, and there was also a grassed
area between the existing sheet piles and the existing brick flood wall. The new one that we
designed, procured and built in 6 months replaced all of this with a higher 1.5m high concrete
wall in front of the existing brick wall, and replaced the grassed area with a structural concrete
slabs Interserve secured the contract to re-construct the existing flood defence wall. As part
of it formed the garden wall to a number of local properties, the new flood wall was
constructed in front of the existing. It consisted of a reinforced concrete wall 1.5m high with
a 3m apron. As this Apron did not fully cover the section to the existing capping beam , an
additional fibre reinforced concrete slab was cast between the new apron and the existing
capping beam thereby preventing water ingress which could scour and undermine the
Value added initiatives
The knowledge gained from our previous experience on tidal river works and our in-house
marine department was crucial in developing the solutions to the river side accesses. The
project benefitted from the use of our own marine plant. Our own marine kit allowed us to
work from the river to do the works, without the need to work on the bank, which was a narrow
corridor. It also allowed us to use heavier plant and maintain better land side access along the 4
meter wide easement. The result was a safer, quicker and better value project.
Engagement with the local community
- Boston College: We had 6 work experience students from Boston College on site taking part
in construction activities and another 60 students came to visit. There were also 12 lectures
to see the works activities and 5 toolbox talks were carried out at Boston College for the
students studying bricklaying, carpentry, plumbing and BTEC construction.
The main site was locatedwithin the port in Boston. All deliveries were taken to a wharf and
delivered to site on the river using a crane barge. This meant deliveries did not impact on the
public, with the reduction of risk to pedestrians and cyclists.
A public relation with toolbox talk was carried out with all operatives who carried around
business cards to issue to any interested parties.
Helped the owners of a containerised cafe to evacuate their merchandise as required by the
We repaired footpaths damaged by the flood event and secured residents gardens from
collapsing into the holes created by the flood water.
Assisted one local in gaining access to this house when his door became blocked by the
movement of his furniture.
A nurse who worked nights, was given a room on several occasions at a hotel away from the
works area at our expense so that her restorative sleep patterns could be maintained.
A boat called 'Boy Ben' sank in the river Haven. Its owner admitted the vessel was a total
loss and that it must be moved for the safety of navigation and to minimise any further
pollution - which is an offence. We righted the vessel and sailed the boat to the port of
Boston to be lifted out. We offered to scrap her, however two locals wanted her and so we
donated it to them. Their intentions were to refurbish, rename and resail her.
"Was out on site this morning in Boston and I have to say the works are looking very good.
Email from our client The Environmental Agency
Interserve are finalising garden remedial works and all works should be completed by the end of this week.
I'm pleased to say that Darryl and the team on site have worked hard to ensure that the site will be handed over defect free.
Well done to all involved and thank you for all your hard work."