Sustainable Drainage and Risk Mitigation Design at Former Landfill, UK

The Project

Project: Integrated Sustainable Drainage, Risk Assessment and Mitigation, UK

Location: Walton-on-Thames

Year Completed: 2017 (EPG UK)


Sustainable Drainage Design, Landfill Gas Risk Assessment, Integrated Design, Landfill Settlement Assessment, Verification

Main SuDS Components:

  • Hydraulic Modelling
  • Permeable Paving
  • Sub-base Attenuation
  • End of Line Attenuation
  • Surface Water Run Off Treatment

The BREEAM rating for the project was Excellent.


Project Description

EPG provided contaminated land remediation and drainage advice to assist the redevelopment of a 40-year old uncapped landfill.


EPG’s final design utilised a high-strength geocomposite, which was laid below a cement-lime stabilised cap to alleviate landfill gas pressure. In addition, a similar system was utilised above the stabilised cap as a drainage and attenuation system.


The scheme also involved the design of a landfill gas mitigation system beneath all buildings, the design of a lateral landfill gas migration barrier and bio-filter system. EPG provided installation supervision and Construction Quality Assurance (CQA) during construction of the mitigation elements to ensure each component met the specification.


The integrated design provided overall cost-savings for the client while addressing concerns of the local council and regulator. More information about our integrated services, including further case studies, is provided here.