ᐅ Design of Rainwater Infiltration (Swale)

Hello everyone,
our building regulations require surface water infiltration. According to calculations from our paver, we will likely need:

1) 80 m² (860 sq ft) with a detention depth of 30 cm (12 inches)
or
2) 25 m² (270 sq ft) with a detention depth of 100 cm (39 inches)

I understand this to mean that I can either have a "wide, shallow" infiltration basin or a "narrow, deep" basin. Is that correct?

If I choose the "deep" option (to avoid losing too much lawn area), could I practically create a planting bed there (with plants that can tolerate occasional wet feet) and use it as an infiltration basin? Does anyone have experience with this?

I also read that the basin must be at least 3 m (10 ft) away from the property boundary. Does this apply on all sides (including where I don’t have neighbors, such as the street side)?

Regards,
VK

Build a soakaway, since you won’t see anything except a manhole cover. The crucial factor is the volume that needs to be filled at the same time.

In my opinion, I am not allowed to do that; it is not surface infiltration. The building regulations explicitly require a basin...

VolkerRacho schrieb:

In my opinion, that’s not allowed; this is not surface infiltration. The building regulations explicitly require a basin...

Haha! Then the basin will be made correspondingly smaller and planted.

We are also required to have soakaways. One person thought he didn’t have to follow that rule and built a French drain instead. He had to remove it and pay a fine.

We also have about 100m2 (1,076 sq ft), 30 cm (12 inches) deep. We simply integrated it into the lawn area and have regular grass growing on top. It doesn’t cause any issues, and I don’t think water has ever pooled there.

That amounts to 30m³ (35 cubic yards). Where is so much water supposed to come from during rain?