ᐅ Evaporation Ponds on Property – How to Construct? What to Consider?

Hello,

we are considering buying a plot of land where the development plan requires the installation of an evaporation basin (with overflow into the parcel ditch next to the property). For every 100 m2 (1,076 sq ft) of impervious surface, at least 19 m2 (204 sq ft) of evaporation basin must be provided.

Searching online has not really helped us understand how to construct an evaporation basin on a private property and what needs to be considered.

We have sent an inquiry to the building authority to clarify questions about the depth, permitted materials, and exact size (for example, whether no basin is required under 100 m2 (1,076 sq ft) of impervious surface, or if at 101 m2 (1,089 sq ft) it must be 38 m2 (409 sq ft), or if it is calculated proportionally). However, maybe someone here can help us get a better idea of how to build an evaporation basin.

Thank you very much for any responses and assistance!

Best regards,
Kerstin

There will be no levelling. One pool with 19m² (205 sq ft) per started 100m² (1,076 sq ft).
How large is your plot?
A 6.3x6.3m (21x21 ft) pond is something you really have to want...

Evaporation is a term I'm hearing for the first time in this context. Are you sure it’s not about infiltration?

If it really is evaporation, I would set it up like a constructed wetland. Ideally, you already have clay soil and just need to compact it well. Then add a layer of gravel substrate and wetland plants on top.

Thank you very much for your responses!
Yes, we are actually talking about evaporation basins, not infiltration. The planned house will not be huge, but there will definitely be 100 m2 (1,076 sq ft) of sealed surface area. Under no circumstances do we want a large pond! The plot is 900 m2 (9,688 sq ft), so there is space available, but also ideas on how to use it...

Our idea was to place the basin on one side of the front yard (5 meters (16 feet) distance between the street and the house) and hide it with attractive planting. However, this only works if the size is proportionally regulated...

Almost forgot, the soil survey has not been completed yet, but we expect sandy soil. Is it possible to create a swamp bed using pond liner? Wouldn’t that then be an ideal breeding ground for mosquitoes?

The house is about 10x10m (33x33 ft), plus a garden shed, garage/carport, and possibly a covered terrace. Even without the paved areas, you're looking at closer to 200sqm (2,150 sq ft) rather than 100sqm (1,075 sq ft).
At this point, I really don’t see how evaporation would help, except maybe attracting lots of mosquitoes. Does the justification for the building permit/planning permission mention anything about that?

Basically, you can also work with pond liner on sandy soil. For a marsh bed, the waterproofing can even be perforated; the plants should stand in the mud for a while but are also allowed to dry out occasionally.