Aardvark project
Contaminated Land Remediation Strategy
| Location: Bristol, UK |
Client: Urban Splash Limited
|
| Date: 2006 to 2009 |
Sector: Waste |
Project Objectives
- To undertake a site investigation of the lake sediments to determine volumes and contamination;
- To design a desilting programme with contractors Kingcombe Aquacare to recover and treat the silts to enable the lake to be restored;
- To reduce the costs and minimise off site disposal;
- To negotiate with the Environment Agency and provide 24 hour cover during the main works period.
Delivery
- Urban Splash’s Lakeshore site is a prestigious project in the Hengrove area of Bristol. The former office and factory site of Imperial Tobacco will be redeveloped to become a major retail park. The Lakeshore element is to provide residential and office space in this innovative development.
- The site spans a small 10,500m2 lake situated in a steep-sided valley. Silt has build up over time from the on stream flow, which over 25 years had formed islands and reedbeds.
- Aardvark estimated that there was 15,000m3 of silt to be removed to enable the lake to be restored. The team used our own boat based sampling rig to extract core samples and undertake a bathymetry survey of the lake bed to determine silt volume and operating depths.
- The sediments contained elevated hydrocarbon and metals. Aardvark was then instructed to design a remediation system to treat the extracted silt and have this approved by the Environment Agency.
- Kingcombe Aquacare, the water specialist contractors were brought in to undertake the desilting works
- In addition, due to site constraints, Aardvark had to design a system to allow the silt to be recovered and water from the pumping works to drain back to the lake. The solution was large geotextile closed tubes, which also allowed treatment to take place on the drying silt. Aardvark designed these GTubes and now uses these for other desilting and water based engineering and remediation projects
- During the process and due to the short lag time of the catchment, the Aardvark team have provided 24 hour cover to be ready on site in the event of an emergency.
