Since 2015, a large scale urban renovation of the Zonnemaat neighbourhood (Zevenaar, the Netherlands) has been underway. In addition to the renewal of paving and addition of more greenspace, works include what is in effect a giant sponge - or Rockflow water management system. This below ground system collects rainwater and allows it to slowly infiltrate back into the earth, thus helping to better manage and infiltrate rainwater.
A large portion of renovation works focus on the public space surrounding Zonnemaat’s Jumbo supermarket and a local snackbar. More parking spaces have been added surrounding these uses to accommodate demand. At the same time traffic speed and volume is managed with the narrowing of adjacent streets. New asphalt paving and brick pavers have been installed throughout, complete with new concrete edging.
This is the situation
We all know however that more paving makes it more difficult for rainwater to penetrate back into the earth, particularly in parking areas as they are subjected to more ground compaction from the weight of parked vehicles. This is particularly the case here at Jumbo and snackbar parking lot where a naturally high water table has left the surrounding land, parking and access plagued by surface water. For this reason, the Rockflow water management system was installed around these areas. The system, which is made from 100% recyclable stone wool is installed beneath the parking lot of Jumbo supermarket. The system acts to effectively store rainwater underground during extreme rainstorms. After buffering the rainwater, it will be infiltrated into the subsoil. Groundwater is thus recharged naturally, rather than placing pressure on the sewer system. Here the system buffer measures 12 m x 28.8 m, with a height of 0.5 m. The system is equipped with sensors to measure and monitor the system’s operation.
