As the temperatures supposedly reach above 30 degrees the coming days, cyclists should be prepared for sudden big puddles and wet legs. The reason for this is ‘bridge cooling’ whereby the bridge authorities have set up a hose system and are actively watering any drawbridges.
This may seem a little strange to foreigners but it is important for the smooth running of both boat and road traffic across the city. The bridges need to stay cool in order for them to continue to be able to open and close. The metal parts of the bridges (like tram lines) expand in the heat and no longer fit together properly if they are not cooled. Cold water is pumped on them in order to keep temperatures down. Last year the heat was so intense that certain bridges stayed too hot and could no longer fit back together. They were kept closed causing disruptions to shippng traffic. Many of the bridges contain tram lines or are public roads so they do need to kept closed in order for the trams and ordinary traffic to cross over even if that causes problems for boats.
The system of cooling the bridges is actually very clever. Water is pumped up via a fire hose from the canal below, then drains away either back down into the canal or onto the roads nearby. There have been investigations into automatic cooling systems but these would be expensive to install and then require regular maintenance. Since the cooling is normally only needed a few weeks or days each year, it is generally agreed that this would not be good use of public money. Cyclists do get wet feet or legs but because of the high temperatures this can be very welcome. Dogs don’t seem to complain about the chance to cool down either.