Plot of land new development area - identify height differences in advance?

Hello. We are getting a plot of land in a new housing development. Now we don’t quite understand the whole topic of land filling etc. What is allowed, what should be done?

Our plot is 24m wide and 30m long. The planned road on the north side (along the 24m) will have roughly the same height level as the plot, at least that is what I can deduce from the topographic maps and the planning measurements of the road.
According to calculations, the plot has a slope of one meter over 30m in length to the back, which is about a 3.3% slope. On the 24m width, the ground on the left is about 0.5m lower than on the right, which is about a 2.1% slope across the entire width.

The house will probably have the finished floor edge about 30cm above street level.
Now my questions:
Assuming I do not change the terrain level, the rainwater can flow off to the back, which is not a problem, but it also flows off to the left towards the neighbor, do I need to do anything about that?
Assuming I raise the terrain on the left so that it is as high as on the right, only the slope to the back remains, and I raise the ground from the house to the street so that the rainwater flows away from the house to the front and back - what do I have to consider? Will the increase be so high that I have to catch something? I am currently thinking that the lateral 50cm is quite a lot, if the neighbor doesn’t also happen to raise their ground. What is generally allowed?

Oh, we don’t really know how to design something like this, where can we get help? I have sent an excerpt from the topographic map. Maybe it’s not that complicated after all. How would you do it? Can you give me tips based on the map? Looking at it, the terrain level compared to the neighbors seems relatively even, right?

On the left, the elevation lines are marked. The plot where the lines are drawn is ours. Can you help? If this is the wrong area please say so, then I will create the post differently. Many thanks

Would be very interesting to me as well. Hopefully someone can provide experience [Erfahrungswerte].

Just asking in advance: Why do you even want to raise the entire property? Couldn't it just stay as it is? I don't find 3.3% that bad.

What are the neighbors planning, are they also raising, or is someone lowering?

If you raise: Is a slope enough for you or do you want to catch it with L-shaped stones to lose as little area as possible?

What does the development plan say about embankment? For many, it, for example, ends at 0.5 m. Is the street already finalized? If not, it can be significantly (!) higher with sidewalks, etc. The road construction office provides information about this.

However, it also flows to the left towards the neighbor, do I need to do something about that?

No.

What do I have to keep in mind?

That the neighbor is not disadvantaged (§37 Water Resources Act - WHG).

Will the elevation increase so much that I have to catch something?

Yes.

The lateral 50cm are quite intense after all

Only someone from Lower Saxony (and further north) can say that . It’s not “intense” because two slope border stones are enough, but for 50cm some solution must be found.

What is generally allowed?

Generally, the state building code allows 2m. However, a development plan can set further restrictions.

Oh, we don’t really know exactly how to design something like this, where can we get help?

With such small height differences, the architect should be able to manage it. For landscape gardeners, it’s daily business, even though I would find it a bit exaggerated here.

How would you do it?

I would change the terrain as little as possible.

Mine would be: a little lower at the front, but not so much that wastewater can no longer drain away (Architect GU knows that), tapering off at the back and side with L stone or, if money is available, with fieldstones, which is much nicer.