The Koningsvijvers and the IJse Valley will be receive clean stormwater from the road by 2025

The Koningsvijvers form a connected chain of 12 ponds. The source region of the river IJse runs through it and feeds this system. The ponds are therefore not only scenic, but also possess cultural and natural value (Natura 2000). To date, rainwater running off the surface of the Brussels ring road is routed directly to the ponds, though that is about to change.