Due to the changing climate, it is not necessarily raining more, but heavier in short periods. Showers with an intensity of 40mm of precipitation per hour are no longer exceptional and are increasingly common. The graph below shows that this picture has changed, with a peak of 76mm per hour in 2011. Terms such as repetition time will be discussed later. When we consider that the average sewer in the Netherlands has a capacity to process 20mm of water per hour, the problem is clear. The sewers are overloaded by the heavy rain, where a logical solution would be to relieve the sewer by infiltrating the soil or rainwater infiltration. Rainwater infiltration means that the rainwater (rainwater) that falls is absorbed by the soil. A fairly logical principle, but due to buildings and pavements, the rainwater can in many cases not enter the ground because it is paved by, for example, roads, roofs or terraces. Rainwater that falls on roofs is traditionally offered to the sewer via the rainwater drainage. Water that falls on the public road flows into the sewer via wells (street gullies). Water that falls on a terrace can also drain into the sewer through a gutter or one chooses, for example, to let the terrace run down to an alley where the water still reaches the sewer. In any case, in many cases it does not end up on land where it can infiltrate locally and the soil collapses, which is actually the natural way.

Bufferen en drainage


Opstelling afkoppelen dak en parkeerplaats