QuadConsult was appointed as part of the Melin Homes design team (working with Vistry Partnerships West) to undertake the Civil and Structural Engineering aspects of the social housing redevelopment at Tredegar Court, Newport, South Wales.  Newport City Council provided funding totalling more than £3.8 million through social housing grants for the demolition of an outdated care home and the creation of an inclusive community of 47 affordable one and two bedroom flats with support network for people aged over 55.  The scheme achieved the full RNIB Visibly Better Living Certification.

The existing building surface water and foul discharged at an unrestricted rate into the existing DCWW combined sewers within the existing adopted roads. Once the existing building had been demolished, the right for connection was severed and discussions were required with both the SAB and DCWW to agree an alternative design following current guidance as set out in Welsh Government standards for Sustainable Drainage Systems.  Following the hierarchy S1 and standards S2 – S6, further site investigation works were required to determine if other means for surface water discharge were viable. Infiltration tests were carried out at several locations across the site resulting in favourable rates as a means of surface water disposal for the entire development’s impermeable areas.

Although rainwater harvesting was not a viable option due to the associated construction costs for the scheme, water butts have been located within the central garden area which offers residents the chance to grow vegetables and flowers, as well as providing a sensory/positive experience for residents suffering with dementia and mental health issues. The SuDS features mean the landscape architecture optimises the green infrastructure in a positive and integrated way reflecting the ethos championed by the Welsh Government statutory standards for SuDS.

Raised Bioretention planters – suitably located during the early stages of the scheme – are a sustainable drainage system designed to manage surface water run-off at rainwater pipe locations surrounding the building footprint. Careful consideration of placement and sizing of such features has been co-ordinated with the design team reducing risk of flooding to the downstream surface water network and improving water quality prior to discharge to ground. Specialised planting also offers richer biodiversity and higher amenity values to the residents and wider community.

In order to follow the standards S2 – S6, a number of surface water treatment and conveyance methods were designed and introduced to provide a minimum two-stage treatment train, improving water quality before discharging to ground through the porous paved structure.  Within the landscape proposals for point of discharge of all surface water downpipes and gullies SuDS features such as high-level bio-retention planters, rain gardens and swales have been incorporated within the design network prior to final discharge to ground.  To maximise the scheme design life and to also reduce risk of surface water flooding in the event of failure to the proposed system or exceedance storm event, an overflow pipe into the combined sewer was also agreed with DCWW as a failsafe. Once the above strategy was deemed acceptable by the SAB, a maintenance schedule was produced for the scheme in line with Ciria guidance which will be adhered to through a private management company. In this instance the scheme was not offered to the SAB for adoption.