Let rainwater seep away?
...or use it!

Rainwater can bring not only blessings. Too much of it quickly becomes a problem and can cause considerable damage through flooding. As a result, urban planning used to focus on protection against water and its rapid removal.

Sewer systems were built throughout the city to remove rainwater quickly and efficiently. However, heavier rainfall events and continued urban densification have increased the pressure on these sewer systems. In combined systems, where stormwater and wastewater are discharged together, the capacity bottleneck propagates to the wastewater treatment plants. For this reason, the decentralized management of rainwater is becoming more and more important to planners all over the world.

The best way to do this is to use the valuable resource of rainwater directly on site.

There are several ways to relieve the sewer system of excessive stormwater inputs and manage precipitation locally:

• Storage and use:

  First and foremost, of course, is the use of this resource, which is decentralized and available almost everywhere in the world. It is used to irrigate plants or sports facilities, in the home or in commerce. Rainwater systems with filters and cisterns or rain barrels are used for this purpose.

• Retention/retention:

  Short-term storage of water using retention cisterns to then slowly release it to the sewer system, reducing peak loads.

• Surface infiltration:

  Surface infiltration occurs over unsealed surfaces, optimally over the revitalized soil zone. Generally, green areas, gravel beds, or pavers with joint infiltration are considered. The water percolates through all soil layers, being cleaned naturally and fed to the groundwater.

• Infiltration below ground:

  With the help of infiltration systems such as infiltration trenches, infiltration blocks or infiltration shafts, rainwater can be channeled directly underground and infiltrated there. The requirements for this vary from region to region and often require approval to protect the groundwater. In some cases, filters must be installed upstream to replace natural purification via the living soil zone.

Only by using rainwater, in addition to saving the precipitation fee, expensive and energy-intensive drinking water can be saved. Learn more about how rainwater can be harvested and used.