When the South East Rivers Trust was tasked with delivering a water attenuation solution for two SuDS planters at a school in Sutton, it took the opportunity to explore innovative solutions and compare different technological approaches to the challenge. Here, we look at how an ACO RoofBloxx geocellular storage crate has helped to provide a flexible sustainable option for the smaller-scale project.
As part of an initiative set up to reduce flood risk in the area, the London Borough of Sutton and the South East Rivers Trust are collaborating on a SuDS raised planter project at a school in Sutton. With funding from the Environment Agency, it will ensure that water entering the nearby River Wandle is cleaner and improves the environment for local wildlife.
The project involved two plant boxes being installed outside one of the priority schools, Carshalton High School for Girls. The plant boxes required water attenuation solutions to store and subsequently release rainfall into the sewer network. Engineers at the South East Rivers Trust approached ACO Building Drainage to ensure the most appropriate solution was selected.
Thinking outside the box
A common approach to delivering sub-base storage is to use a simple gravel layer, but as Ed Byers at the South East Rivers Trust explains, this particular project offered a unique opportunity to trial an alternative approach:
“We decided to compare two technologies: opting for gravel in one planter, and geocellular storage crates as the sub-base layer in the other. We knew that this would increase the void space when compared with gravel – offering approximately 90% volume versus 30%. This ultimately ensured we could meet the required storage capacity for the planters, as specified in the designs.
“We selected ACO RoofBloxx, because of its ability to stack, which was important due to the height of the planters. It was one of the few products available that met the requirements. They’re stackable, sufficiently flexible to be used at different heights, and easy to cut, all of which helped maximise the space within the planter.
“RoofBloxx is a great value product, and provides more storage than a simple gravel layer. It is also available in relatively small quantities, which makes it ideal for smaller-scale projects where large volumes of stock are not required.
Measuring performance
As part of the project, the South East Rivers Trust will compare the performance of RoofBloxx with a more traditional gravel layer. Four pressure transducers have been installed to measure water levels across the plant boxes, which are combined with v-notch plates to measure flow in and out of the planters. This is set to provide data on the relative ability of attenuation solutions to store and slow down the flow of water into the sewer network.
Adam Cane, Knowledge Manager at ACO, comments: “This is a unique approach to what is a fairly common application. This will enable the trust to make informed decisions, and ultimately provide informative guidance to industry in the future.”
“Monitoring of the boxes will continue for a year. South East Rivers Trust’s innovative approach is a fantastic example how different organisations can work together. Support from expert product manufacturers such as, ACO Water Management, can help deliver the technological advancements required to meet varied challenges.”
More information on ACO RoofBloxx can be found here: https://www.aco.co.uk/products/roofbloxx
