Castlegate, Caerphilly

Project Title: Castlegate, Caerphilly

Client: Walters Land Limited

Relevant Disciplines

• Ground investigations
• Foundations
• Construction materials
• Contaminated land
• Soil and groundwater risk assessments
• Remediation strategy design

Project Description

The 60-acre site known as Castlegate in Caerphilly operated as a landfill between the 1940s and 1960s during which time it received a range of chemical and other industrial wastes. Much of the waste was organic in nature and had been deposited sporadically in drums. Since closure of the landfill in 1968, the site has remained un-used principally because of the potential environmental and human health risks posed by the waste.

Intégral Géotechnique was appointed by Walters Land to carry out geotechnical and geo-environmental investigations to assess the suitability of the site for a mixed development of residential, commercial and community-based land uses. These investigations were carried out in association with Sladen Associates, specialists in soil and groundwater numerical modelling, and whom had carried out extensive investigations and assessments of the site in the past.

Based on a comprehensive programme of investigations including trial pitting, cable percussion and rotary drilling, specialist laboratory chemical testing and groundwater monitoring, numerical assessments of the risks posed by the waste to controlled waters and potential residential end-users were carried out. The assessments identified areas of the site requiring remedial action and a comprehensive remedial strategy for reclamation and remediation of the site was developed.

The remediation strategy was developed in consultation with the Environment Agency and the Environmental Health Department of Caerphilly County Borough Council and formed an important part of a planning application made by Walters Land for redevelopment of the site.