Six sevenths of all precipitation
ends up in the sea. Only 1/7 falls on land. This 14% is of
vital importance for human life and for the environment,
since all life is based on the presence of water. So it
makes sense to deal with rainwater sensibly.
The problems
Where settled areas are sealed off, a large proportion of
rainwater and the water from melting snow is diverted
straight into the sewers. This gives rise to the following
problems:
- Less groundwater can form
- Increase in high-water peaks in the main outfalls
- Extra loads on the sewer construction authorities and ARA (waterworks authority) due to clean rainwater.