Primary School Kirkeveldsje - Water Management Case

Rockflow in the practice of urban planning


Stone wool can absorb up to 95% of its weight in water


550.000 l water absorption in 30 minutes


Water released within 24 hours

Rockflow in the practice of urban planning

Rockflow from Lapinus is used for: 

  • the prevention or reduction of local flooding
  • the reduction of peak discharge to the sewer system
  • the reduction of operational (maintenance) costs

Ronald Pluijmakers. Projectmamanger at Royal HaskoningDHV about his experience with Rockflow:

“My colleagues of the department ‘Water’ were collaborating with Lapinus in the development of Rockflow for application in the public space. I heard about their involvement at around the same time they were looking for a suitable pilot project. After learning about Rockflow I was quickly convinced of the benefits and felt it would be a perfect fit with the project at the elementary school in Schimmert which I was working on at the time. I pitched the idea to the municipality and manged to convince them rather quickly. Together we made it into a very successful first pilot."

Jos Last, Manager Project design and preparation at the Municipality of Nuth:

Looking purely at the hard surface of the school it may not seem like a huge amount, however it turned out to be around 5000 m2. Together with the surface area of the playground it amounts to 12000 m2. The space underneath the playground alone was too small to create enough buffer capacity. This meant we also had to include the available volume below the driveway towards the school as well. In this thigh space we needed a solution that offers enough flexibility. Stone wool can easily be adapted to the space available and is very easy to handle; This is one of the biggest benefits of Rockflow if you ask me."


“It collects the water into it. Once the rain has calmed, the water flows through the buffer back into the sewer. Perfect System!”

“It was very disruptive. Especially with heavy downpours, it used to be really awful here. All the rainwater flowed into the street and houses”

Project details

Location   Schimmert, Municipality Nuth, The Netherlands
Installation date July 2017
Application  Low density > Pedestrian area 
Design   45 mm in 30 min.
Catchment area 12.000 m2
System size  550.000 liter + 50% extra
Project volume  820 m3
Rockflow elements  8000 pieces
Engineers Royal HaskoningDHV