SUSTAINABLE URBAN DRAINAGE
Hewitech design, manufacture and install Sustainable Urban Drainage systems.
Our systems incorporate “engineered” SUDS consisting of modular storage systems along with “open” SUDS such as swales, ponds and lagoons which offer the environmental benefits of amenity, water quality and bio-diversity whilst combining the commercial development needs to store stormwater water below ground.
Variobox SUDS systems for stormwater retention and infiltration are the strongest available, proven by rigorously testing for long term performance. Variobox Plus with a vertical test loading of 700kN/m² and a lateral test loading of 200kN/m² enable the Hewitech system to be designed and installed at greater depths than other crates available within the industry.
All modular storage systems should have a site specific assessment of the long term loads, vertically and laterally imposed on the structure by live loads (traffic) and dead loads (construction above the tank).
The industry standard for this is the CIRIA C680 calculation that incorporates a 2.75 material safety factor applied to the crate compressive test strength. Hewitech’s bespoke software to C680 will provide engineers and contractors with the requisite structural assessments.
Access and maintenance to the engineer’s design is achieved by incorporating the Controlbox with a 500mm open channel.
The maintenance channel is used to clear debris from the system using traditional drainage jetting techniques.
Variobox is available in a wide range of depth configurations, 50,65,80, 100, 150, 200, 300, 400 and 600mm.
This allows the engineer great flexibility in designing tanks that best fit the site’s drainage constraints and available space for construction.