Eco drainage system utilised at Bridgend development
22 December 2021
A new housing development in Bridgend is one of the first in Wales to use a sustainable drainage system designed to mimic nature and allow clean water back into the ground.
Guided by the Flood and Water Management Act, Persimmon Homes has implemented a sustainable urban drainage system at the 106-property Tir Y Bont development, part of the wider Parc Derwen regeneration scheme in Coity.
Sustainable drainage systems (SuDS) are drainage systems that improve or do not harm the environment. They efficiently and sustainably drain surface water, while minimising pollution and managing the impact on water quality of local water bodies.
Measures at Tir Y Bont include permeable shared drives, as well as rain gardens and a swale. Swales are shallow, broad and vegetated channels designed to store and/or convey runoff and remove pollutants.
Mike Williams, Head of Engineering at Persimmon Homes West Wales, said: “We’re pleased to be implementing a thorough sustainable drainage system at our Tir Y Bont site, working in conjunction with Bridgend County Borough Council and relevant stakeholders.
“These types of systems will be in place at all future developments across Wales, but Tir Y Bont is our first development where work has already started. The overriding aim is to mimic nature as much as possible and treat the water at the point at which it falls to the ground rather than pipe it all away as quickly as possible.
“This not only helps to reduce localised flooding but also helps clean water by removing contaminants naturally, and provides enhanced amenity and biodiversity. Persimmon is committed to a long-term sustainability plan and this is just one example of that being put into practice.”
A key feature at Tir Y Bont is permeable shared drives and rain gardens, which allows water to filter through rather than running off it. This filtering process is very effective in removal of pollutants such as sediments, trace metals and organic matter.
In this case, Persimmon has also included gaps in the kerbs for water run-off into a two-metre wide rain garden. The water runs through subsoil in a trench, where it is channelled away by a pipe and discharges to the main swale.
A swale has been utilised to lead surface water overland from the drained surface to a storage system. Rainwater which flows into it moves slowly through the grass area. The grass acts as a filter as the water passes through it. For the private driveways, a deeper subbase is use rather than pipes to filter the water away.
Persimmon has engaged with specialist engineering consultants to create the thorough drainage plan.
Councillor Stuart Baldwin, Cabinet Member for Communities at Bridgend County Borough Council, said: “Sustainable drainage systems such as this one at Tir Y Bont will become increasingly important in years to come. They offer an environmentally friendly and effective way of dealing with surface water runoff within built-up areas, and it is great to see that Bridgend County Borough is among the first areas in Wales to benefit from them.”
Tir Y Bont is the final phase of housing at Parc Derwen, where more than 1,500 homes have been built.