Contractor W Longs is this week putting the finishing touches to a comprehensive Sustainable Urban Drainage System at RAF Northolt in Cambridgeshire as part of a £600M modernisation of living accommodation on the site.
The project at RAF Northolt is part of the £600 million MoD Single Living Accommodation Modernisation (SLAM) scheme designed to deliver living accommodation for MoD personnel. Polypipe Civils has supplied a bespoke hybrid drainage system for the site.
The original project specification was changed from a concrete box culvert due to issues with rising material costs and concerns over the performance of the product in times of high-flow water run-off. However, a solution was needed that was capable of storing the required water capacity whilst accommodating difficult site constraints. The modular construction of Polystorm and Polystorm Lite allowed the cells to be connected together to form almost any shape and storage capacity.
Working with contractor W Longs, Polypipe Civils offered the MoD a value engineered, hybrid system to cope with uneven burial depths on-site. Following consultation with both the MoD and W Longs, Polypipe Civils also designed a manifold system to improve hydraulic performance.
Approximately 3000 Polystorm and Polystorm Lite cells have been installed on-site to provide an attenuation solution to cope with surface water run-off from both hard standing and roof areas.
Polystorm consists of individual cells that can be interlinked in any configuration required giving greater flexibility in design. The cells have a minimum compression strength of 40 tonnes per square metre and although each unit only weighs 9 kilograms it has a storage capacity of around 190 litres.
Polystorm Lite retains the same storage capacity and health and safety benefits as Polystorm but is specifically designed for non-trafficked applications. The cells have a minimum compression strength of 20 tonnes per square metre, allowing the structure to withstand general maintenance vehicles such as grass cutters, yet each crate weighs just seven kilograms.