Northaw House, Hatfield

Detailed Surface & Foul Water Design Package

Services offered

  • Surface & Foul Water Drainage Strategy (Planning condition discharge)
  • Detailed Surface & Foul Water drainage Design

The brief

Civilistix Consulting Engineers were appointed to initially prepared a detailed surface & foul water drainage strategy for reserved planning condition discharge and then to carry out subsequent detailed design for this high-end residential development.

What we did

The site was rural and located within ample green space allowing us to adopt a truly traditional open SuDS design approach. We utilised dry swales and filter drains to drain the main access roads providing treatment to runoff over and above what conventional gullys can provide. Surface water flows were controlled to the 1 in 1 year greenfield runoff rate before being discharged to a nearby watercourse. In order to provide the attenuation volume necessary, we provided a large attenuation basin which further to functioning as an important drainage feature, was also an integral part of the attraction of the development providing important ecological and recreational benefit.

Existing High and Medium pressure gas mains crossed the site and our drainage design had to therefore be coordinated with them. This meant reducing as far as possible the amount of crossings required and where crossings were unavoidable, dropping the drainage system to ensure gas provider requirements could be met.