ACO StormBrixx geocellular attenuation and infiltration crates from ACO Water Management are regularly used as a vital part of sustainable urban drainage systems (SuDS). However, at the Rushden Lakes retail development, the landscape architects for the project identified a different use for StormBrixx in the creation of 13 tree pits throughout the site. The high void capacity crates were ideal for allowing root growth and were strong enough to protect against load stresses from trafficked areas above. The flexible, snap-lock construction of ACO StormBrixx also meant various designs could be incorporated easily in different parts of the site.
Part of a SuDS project
The SuDS system throughout Rushden Lakes is supported by channel drainage and oil interceptors, in order to effectively and safely manage surface water that needs to drain into the surrounding wetlands. Given the site’s proximity to the lakes, flood risk was higher, meaning it was critical to mitigate any pollution risk from surface water run-off from the car park and other hardstanding areas.
Boulevard and car park
A key element of the design project is the inclusion of 13 types of tree, as well as various other plants, sensitively located in the retail park. Trees are positioned throughout the car park and the central boulevard, and a pedestrian corridor runs from the retail area to the waterfront.
StormBrixx used as tree pits
Due to soil compaction, it is quite common for trees to be planted with insufficient space for full mature root growth. Over-compaction can prevent oxygen reaching the roots, as well as inhibit drainage, both of which can severely limit long-term tree growth.
ACO StormBrixx has good vertical and horizontal load strength. The vertical load strength is integral to the Rushden Lakes car park, where the supporting tree pits jut out and are subject to site traffic. In all areas, the strength of the structure prevents soil compaction and allows largely unrestricted root growth through the open geocellular structure which as a void ratio of 95%.
A geotextile wrap and the structural strength of ACO StormBrixx protected the soil from the many dangers of soil contamination during construction. By filling the StormBrixx tank void with clean and fertile soil, and then wrapping the whole installation in a geotextile material, the landscape architects were able to keep all the soil in place and free from contamination to promote healthy root growth.
Thanks to the easy snap-lock construction of ACO StormBrixx, various tree pit configurations were able to be installed at Rushden Lakes. These included a cross design in a car park node where one installment of StormBrixx protected four trees in one construction, as well as a half-lap concentric ring pattern around some trees, aided by the system’s brick-bonding for extra stability.