Tetra Tech delivered a broad range of services during the decommissioning of Aberthaw power station, including topographical, watercourse and utility clearance surveys, hydrology services, unexploded ordnance surveys and land contamination ground investigation services.
RWE Generation UK plc (RWE) commissioned Tetra Tech to carry out a full 3D topographical survey of Aberthaw power station and the adjacent ash mound as well as a hydrographical survey of the river thaw. The power station is currently being decommissioned and this survey will support the potential sale of the site.
The team also undertook PAS128 underground utility clearance surveys of over 60 locations around the site to enable the safe completion of borehole and trial pits for the ground investigation survey.
Challenge
During the delivery of these surveys, 150 hectares of land and watercourse was surveyed.
A comprehensive watercourse survey was required over c.2kms to support the Tetra Tech hydrology team prepare models for a flood risk assessment. The power station and ash mound site is bisected by the river thaw and as such, posed a challenge to the delivery of the project. A section of the river is canalised which meant that there was a significant health and safety risk regarding both access and data collection. In addition, the watercourse is tidal bringing further issues for manoeuvring along the area by boat.
Solution
Working together with external contractors to address the hydrographical surveying elements of this project, the survey team were assisted on site by a specialist watercourse safety team who provided safe access and egress as well as putting a comprehensive rescue plan in place. The structures were surveyed using laser scanning technology at low tide to limit site time and a remote-control catamaran mounted sonar system was deployed to capture bed level data where suitable.
Benefits
All topographical, watercourse and utility clearance surveys were completed on time and within budget, and most importantly without incident on a site that posed a number of health and safety challenges. All underground utilities were avoided during the ground investigation works within an area containing multiple services.
Further services provided by Tetra Tech
Working together across several specialist disciplines has allowed Tetra Tech to achieve value and seamless delivery of this decommissioning project to RWE. The services provided on this project include:
- Ground investigation and land contamination risk assessment services to determine the potential for contamination to be present within the soil and groundwater
- Bespoke fluvial and tidal modelling services to assess the flood risk posed to the prospective development site
- Cultural heritage desktop surveys to examine the archaeology and history of the Aberthaw site
- Transport planning services to provide advice to RWE on the potential impacts of demolition traffic on the local roads and routes to motorway network
- Data services to collate all utilities records for the site
At a glance
Client
Aberthaw Power Station
Location
South Wales
Services
3D Topographical surveys, hydrographical survey, PAS128 underground utility surveys, unexploded ordnance surveys, watercourse clearance surveys
The project featured in this article was undertaken by RPS, A Tetra Tech Company and originally published on RPSgroup.com. In March 2026 RPS rebranded to Tetra Tech.