In the ‘from façade to façade’ redevelopment of Amsterdam's Nieuwezijds Voorburgwal, climate-adaptive measures were implemented as part of the Amsterdam Rainproof initiative. These included the construction of a water storage and infiltration system, which collects water from a heavy downpour and then infiltrates it in controlled doses into the ground.
"Amsterdam Rainproof is a standard we have set as a city," says Jora Slinger, geohydrologist at Waternet. "It means that the city must be able to withstand a 70 mm/hour downpour, which falls about once every 100 years. In such a downpour, the water should not rise too high or come up to against the façades. Using computer models, we looked at where in the city bottlenecks occur during extreme downpours, and the Nieuwezijds Voorburgwal turned out to be one such spot. Using the computer model, we also calculated how much buffer capacity is needed and where it should be located. The problem on the Nieuwezijds Voorburgwal was fitting it into the narrow street in the busy city centre, where the ground is full of cables, pipes and other utilities." Despite the challenges, an infiltration system with a capacity of nearly 700m3 had to be installed there, in order to meet the Rainproof standard.