Sponge City

The other day I read the German word Schwammstadt. Then I remembered Sponge Bob lives in Bikini Bottom, not Sponge City. Confused, I looked on the Internet:

The term "sponge cities" is used to describe urban areas with abundant natural areas such as trees, lakes, and parks or other good designs intended to absorb rain and prevent flooding.

©frontiers

The building blocks of a sponge city for water management are retention in rain gardens and bioswales, infiltration into the soil, storage in reservoirs, purification in treatment plants, and final discharge into rivers.

Water harvesting (©Love Your Landscape)

The earliest "sponge" Red Baron remembers is the good old rain barrel.

Climate change means, on the one hand, severe droughts like in Germany's northeast and, on the other hand, floods due to intense (local) rainfall.

So water management becomes essential. When it rains, this rain must seep away, not run off. In cities, more open, green spaces are needed - facades and roofs must be greened so that water can be kept on site.

Greened living environments provide less hostile conditions for humans and animals in the impending hot and droughty summers. Sponge cities help us meet the challenges posed by extreme weather.

In a sponge city, spaces are created capable of absorbing large amounts of water and releasing it in a time-delayed manner.

Measures to be implemented are roads that are changed in the angle of inclination so that they can drain water in a targeted manner (stormwater roads). Other roads may be lowered to serve as detention roads. Finally, there are green roads, i.e., landscaped streets where water can percolate into plant beds, tree trenches, and swales next to the road.

Squares and parks are modified or redesigned as retention basins to hold as much water as possible. All these measures will provide better protection against extreme weather events.

Red Baron sees a problem in water losses due to evaporation. They increase exponentially with higher temperatures. So if a city "sponges" too much of the incoming rain, the final water discharge into rivers will be diminished.

In addition, cities not so efficient with sponging rain will use water from rivers. Counting in the reduced meltdown of shrinking glaciers will lower the water levels of rivers.

Last summer, we experienced such a situation with the Rhine River hampering navigation considerably. Due to the low water levels, ships transporting fossil fuels or building materials could only be loaded half, increasing transport costs significantly.

Creating sponges for water retention is good but will not compensate for climate change, along with its little rain and high temperatures.

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