Background

The Barry Business Service Centre (BSC) is a commercial development in a dense urban location in South Wales, surrounded by existing buildings and infrastructure. As part of the construction of a new car park, Vale of Glamorgan Council sought to review and upgrade the site’s surface water drainage strategy to ensure compliance with Sustainable Drainage Systems (SuDS) standards.

A previous drainage design incorporating porous paving had proven to be unsatisfactory, prompting the council to explore alternative solutions that could deliver effective water quality treatment, attenuation and urban landscaping within a highly constrained footprint.

The challenge

The project presented several overlapping challenges:

  • Limited space within a tightly constrained urban site
  • The need to meet SuDS and Environment Agency pollution removal requirements
  • Managing surface water quality before discharge into the adjacent docks
  • Integrating drainage infrastructure with attractive landscaping
  • Finding an alternative to traditional SuDS features such as swales or reed beds, which were not feasible due to space constraints

The council required a compact solution capable of combining multiple SuDS functions within a single system.

The solution

Marshalls supplied three Hydro BioCell™ units, one of the first UK installations of this innovative precast biofiltration and bioretention system, working in partnership with Hydro International.

The Hydro BioCell™ combines several SuDS components into a single, compact structure. From the surface, it appears as a standard tree or planting box, with shrubs or trees emerging through a decorative grating set within conventional concrete paving. Below ground, each unit incorporates a concrete structure containing a mulch layer and a bespoke soil filter medium, delivering consistent stormwater treatment and attenuation.

The system connects directly to surface water drains, infiltration systems or soakaways, enabling effective treatment of runoff before discharge. In this case, it allowed the council to meet Environment Agency requirements for pollutant removal from stormwater prior to discharge into the storm sewer and adjacent docks.

“Features like swales and reed beds were not feasible for introducing more biodiversity, as there was not enough room in this typical urban location. The three BioCell units enabled us to meet the Environment Agency requirements for removing pollutants from stormwater run‑off before discharge.”

Keith Sulsh, Drainage Engineer at Vale of Glamorgan Council

“The Hydro BioCell combines several different SuDS features within one system, which was not met by any other solution the council looked at.”

Keith Sulsh, Drainage Engineer at Vale of Glamorgan Council

The outcome

The Hydro BioCell™ installation delivered a space efficient, SuDS compliant drainage solution that met both regulatory and aesthetic requirements for the Barry Business Service Centre car park.

  • Effective stormwater treatment and attenuation within a compact footprint
  • Improved protection of receiving waters through pollutant removal
  • Integrated urban planting and landscaping at surface level
  • A viable alternative where porous paving and conventional SuDS features were not suitable

The project demonstrates how innovative, precast SuDS solutions can unlock sustainable drainage opportunities in densely developed commercial and civic environments.