Situated in the heart of Cardiff, the Callaghan Square highway and public realm improvement scheme comprises the realignment of Callaghan Square, St Mary Street, Penarth Road, Tresillian Way, and Custom House Street, including junction improvements at Bute Street, Saunders Road and Hope Street. The scheme has secured significant LUF funding and is seeking the pedestrianisation and public realm enhancement of large parts of Callaghan Square and Penarth Road and the provision of segregated active travel routes through this area of the City Centre, whilst incorporating the Cardiff Cross Rail tram line running from Central Station through the square to Cardiff Bay.

Burroughs have been commissioned by Cardiff City Council to provide drainage, SuDS and associated landscaping design and utilities coordination services for this prestigious highways, rail and public realm scheme, taking the scheme through concept design, detailed design and construction support. The concept design stage has recently been finalised, with Burroughs instrumental in providing innovative drainage and SuDS optioneering and specialist advice as part of the multi-disciplinary design team with significant engineering and environmental constraints. Burroughs have maintained a practical and collaborative relationship with the Cardiff Council Highways and Drainage team, the SAB Officer, TfW, the masterplanners and DCWW developer services throughout the design development to ensure all key stakeholders are engaged and can inform and support the proposals.

Schedule 3 to the Flood and Water Management Act 2010 is a legislation that was implemented in Wales on 7 January 2019 and introduces standards for the design, construction, maintenance and operation of new sustainable drainage systems (SuDS) and also establishes an approving body (SAB) in local authorities that are responsible for approving and adopting the drainage systems. Cardiff Council is one, if not the leading Authority on its implementation across Wales and the UK and as part of our design support role on this scheme, we have also been developing a standard green infrastructure/SuDs design guide that the authority can use to inform their drainage design requirements for all future schemes as part of adding biodiversity and climate change resilience whilst simultaneously creating improved provision for walking and cycling. As with all retrofit infrastructure improvement schemes, implementing green infrastructure drainage such as raingardens and treepits, are often difficult to facilitate in urban areas with the density of existing below ground infrastructure and constraints that are very costly and complex to relocate.

As part of our drainage design role, Burroughs have commissioned further drainage surveys to ensure any gaps in the previous surveys have now been closed and the project team are now moving into detailed design and formally commencing the SAB process. During the design development, Burroughs have also identified a significant opportunity to improve the existing surface water system through the area and divert over 5 hectares of clean, treated surface water away from the combined DCWW sewer network into the River Taff. This is a once-in-a-generation opportunity to remove significant flows from a largely pumped drainage system and is also going to present further improvements and surface water removal throughout a large area of south-west central Cardiff by enabling new future developments to connect to a new separated surface water outfall. This is ongoing and would provide a significantly more sustainable gravity drainage solution for the centre of Cardiff and the local community if we can implement.

The scheme had a concept design approved in Spring 2024 and is currently in the early stages of detailed design along with partners at Transport for Wales, with an Early Contractor Involvement contractor to be commissioned in the summer to support the completion of the design through 2024 and a proposed start on site in 2025.