Assessing flood risk on the access road to the Bro Tathan Business Park in St Athan, where key tenants include Aston Martin’s new factory, we designed fluvial and surface water flood alleviation measures to ensure the new transport link and local communities are safeguarded from future flood events.
Creating the new Ffordd Bro Tathan access road was critical to the Welsh Government’s plans to regenerate the former MoD site, create the Bro Tathan Business Park and free up developable land in St. Athan, south Wales. Additionally, Boverton has suffered frequent flooding in the past and the construction of the Ffordd Bro Tathan access road provided an opportunity to improve flood risk in the area.
The road crosses two key watercourses, Llanmaes Brook and Boverton Brook, and Awe chose to design the road to act as a flood defence to help reduce flood risk to Boverton village downstream, as well as to road users. This also enabled the Welsh Government to make significant cost savings given the original inherited design included a 70m-span bridge crossing the flood plain which was designed out.
We undertook extensive flood modelling of the Llanmaes Brook and Boverton Brook catchment through the updating of the existing fluvial hydraulic model and creation of a new pluvial hydraulic model to understand the existing flood risk to the region. We then developed and assessed a range of flood mitigation options and created a detailed design for the preferred option, that created an effective solution using multiple flood attenuation measures including swales and flood relief culverts. We also undertook the Flood Consequence Assessment for the planning phase of the project.
We liaised closely with Natural Resources Wales, consulting them on our development of the hydraulic models, the flood alleviation measures and incorporating environmental mitigation and enhancement measures. The scheme is complete and has opened up important developable land in St. Athan whilst ensuring effective mitigation of both present day and future flood risk to the local community.