Location Marga Klompébrug - bridge

Here you are on or near the Marga Klompé Bridge, which has almost the same design as the Paardenveld Bridge, located a bit up north, past the shopping mall and the big knot of bridges at Vredenburg. The same white fencing, the same semi-circular underpass along the water for pedestrians, the same holes in one of the bridgeheads that birds and bats can crawl into. Fifteen years ago, the Willemsviaduct, or overpass for cars, was located on this spot, where six of the car lanes of the Catharijnebaan went under. Now you see water flowing again through restored canal under the bridge. But that's not the only water here.

When the canal was filled in, in the seventies, an enormous underground concrete sluice shaft was constructed between locations Paardenveld and Willemsplantsoen. This big concrete tube allowed the water from the canal to flow underground to canal the Oudegracht near the Weerdsluis. That tube has largely been demolished to make way for the open water of the canal again. But under the high green bank in front of the Willemsplantsoen, opposite the Moreelsepark, part of that sluice shaft has been given a second life as a huge Water-Storage-and-Sedimentation-Basin, in Dutch it’s called a Berg-Bezink-Basin, a BBB, with a volume of one point six million litres. Under the Rijnkade, hidden behind the brick quay in front of the SHV building, is a second, newly built BBB of the same size. Those two basins are there to collect large amounts of water when it rains harder than the city's sewer system can handle. If the water in the sewer rises above a certain level, it used to overflow into the open water of the canals. Now the water is running into these BBBs first. As soon as the heavy rain is over and the water level in the sewer drops again, the water is slowly pumped back into the sewer system. In this way, the drainage of rainwater is spread over a longer period, and dirty sewage water is prevented from ending up in the canal. Together, the basins can collect about 3.2 million litres of excess rainwater. That is about a hundred small family swimming pools together.