Infiltration of rainwater, which method?

Evolith, where are you building? Sounds like our construction area

Evolith, where are you building? Sounds like our development area

In Marl. [emoji4]

There are some differences between the municipalities. Rainwater that cannot infiltrate into the soil due to sealed (or partially sealed) surfaces must:

a.) be infiltrated on the property via infiltration systems (trenches, basins, or shafts)
b.) be discharged into the municipal rainwater drainage network (if available)
or
c.) be discharged into the regular sewer network

With us, it is also the case that rainwater from all (partially) sealed surfaces (roof, terrace, yard/driveway/parking space) should preferably infiltrate on the property. Discharge would also have been possible here, but probably would not have saved money and would also mean additional drainage fees.

We had the infiltration system calculated through our construction supervisor and the result was 13 boxes from Intewa with the dimensions 80*80*36 with a total volume of 2.78 m³.

According to our soil report, we have a kf-value of 5*10^-5. The water level on the day of the investigation was 1.9 m - 1.7 m. However, the report also stated a design water level of 0.4 m below the reference point. That is probably our worst-case scenario, right?

Wow...I only have one question: according to the installation instructions, the infiltration trenches must have a distance of 1 meter from the highest expected groundwater level. At 1.7 meters, the coverage is already tight, at 0.4 meters impossible. How is that supposed to be achieved?

We also have to infiltrate on the property and exchange soil for it. And of course, all sealed surfaces count, not just the roof.

Well, I have to disappoint you. We do not have to include paved surfaces (as long as they are not sealed with asphalt). As long as classic paving is laid with a slope towards the street, it is assumed that it’s okay. Only the roofs are the subject of consideration.

You don’t disappoint me with that.. That’s great.. Your municipality is probably happy that the sewers are properly flushed sometime, because the pipes are so big that otherwise hardly any proper flow velocity is achieved...

In the end, it’s a matter of personal judgment... Everyone has to calculate and decide for themselves whether they want/are allowed to discharge or prefer to let it infiltrate...

The next person comes along and wants to wash their laundry with the rainwater or water mom’s tulips...