Water
A conversation with Bettina Neff from the Protestant Cemetery Association Berlin City. The audio is only accessible in German.
As Sandra Mänty has told us, water plays an important role not only for plants, but also for birds and insects. In fact, water is a vital source for all life on earth and faces more and more scarcity even in and around Berlin. While the groundwater level drops, our consumption and that of companies is rising for the last few years. But how does the New St. Jacobi Cemetery deal with water? Bettina Neff from the Protestant Cemetery Association told us more.
Bettina:
For us, of course, the question is largely: How do we keep rainwater in the cemeteries? That's a fundamental question for the survival of the greenery in the cemetery. There's still far too little rainwater management in cemeteries in general; most cemeteries still run their irrigation on drinking water. This is bad in many ways. There is no targeted infiltration and the collection of rainwater is not yet really regulated in many cemeteries.
There are always selective individual projects. Here at the chapel there is also a cistern with an infiltration ditch and a water connection that Prinzessinnengarten uses to use the rainwater—but that is often very selective. We did the first big project at a cemetery at Friedrichshain with the district office of Friedrichshain-Kreuzberg. There is a huge rainwater cistern and also a weather control system. This cistern is supposed to work intelligently via a weather control, which means it is supposed to know when heavy rainfall events are about to occur. When it is almost full, it drains water to be able to absorb water and saves water for dry periods. To make it work even more intelligently, tree sensors have also been installed to see how much water the roots actually need. Because trees should also be trained. It doesn't make sense to water trees too much.
If you want to harvest rainwater, the inner-city cemeteries are actually perfect because they are surrounded by roofs and you harvest the rainwater from the roofs. So you can also process what just comes down, but of course it's much better if you can additionally discharge the roof surface water.
That's still a long way to go. Most of the time, there are different property owners. As with the cemetery, there are probably many different private owners of each individual house, with whom you then have to conclude contracts and so on—so that's a thick board that has to be drilled. Berlin is working on this. In Landsberger Allee we have now signed a contract—which has probably never happened before—that is attracting a lot of interest. It's exciting and probably different every time, because it also depends on the interests of the respective owners and how you then regulate that one party gives up the water forever and the other party promises to take the water forever.
It starts to cost a lot of money. It's about this sponge city principle and the disconnection from the combined sewer system that we still have in Berlin; which sometimes leads to flooding on heavy rain days when too much rainwater goes into the system. It's also a total waste, because all the wastewater goes into the combined sewer system, while the rainwater could actually be used much better for the street trees and green spaces. But for that, you would have to collect it and distribute it in a targeted manner.