Working on behalf of the Environment Agency, Team Van Oord is about to begin work on an innovative scheme aimed to provide improved protection from flooding to households, infrastructure and agricultural land adjacent to the West Somerset coast.
The village of Stolford and surrounding area – located on the Bristol Channel, just east of Hinckley Point – is currently protected from flooding by a shingle ridge that needs regular recharging.
This is viewed as unsustainable over the longer term, so a new approach will transfer the primary flood defense function to an existing earth bank further inland, reported TVO.
However, the existing bank needs to be improved so that it can withstand 1:100 per year water levels and waves: it should remain intact under those storm conditions, and even then any wave ‘overtopping’ has to be of an acceptable level, added TVO.
The £850k scheme at Stolford will see block revetments, as developed in the Netherlands, deployed instead of the conventional rock revetment approach.
Jaap Flikweert, Leading Professional Resilience with Team Van Oord partner Royal HaskoningDHV, said: “The project team reviewed the initial standard rock revetment design and agreed there was a need to look at alternative solutions. We added ‘Dutch style’ block revetments to the shortlist, and developed outline designs of all options to meet the technical requirements.”
“We compared these options on costs and environmental impacts and opportunities, and identified the Hillblock product as the preferred solution,” said Jaap Flikweert.
The proposed solution was taken through the regular permitting processes and agreed by the Environment Agency, with funding then secured. The project team then worked to overcome the practical challenges associated with delivering an innovative solution.
He continued: “Block revetments are the default solution in the Netherlands for protecting sea banks against waves. Hundreds of millions of Euros have been spent on levee improvements since 1998, and millions more on research and product development to optimize solutions.”
“However, all of this knowledge and experience is difficult to access outside the Netherlands, due to the specific conditions there and the language barrier,” added Jaap Flikweert.
Jaap Flikweert concluded: “The design confirmed block revetments as a more cost-effective option than a traditional rock revetment, even when the blocks are produced in, and transported from, the Netherlands – even if we had not secured the Partners for Water funding. This means there is a good chance that block revetments can be a competitive option for many other coastal defense projects in the UK and worldwide.”
The implementation of the Stolford scheme, including transport to site and placement of the blocks, will commence in early November and should be complete before the end of 2018.