Lowering of groundwater according to soil report - Your experiences?

I just checked regarding water ingress into the drain pipes. The manufacturer states: 80 square centimeters of water ingress area per meter. That means for 50m length = 0.4 square meters of ingress area. After deductions for water surface tension and resistance due to the filter mantle, etc., there remains enough "free" water ingress area to achieve the required 13.3l/s. The slope is rather decisive here. Because if water accumulates in the pipe, the ingress area is "blocked." It will probably be fine :-)

It will go wrong anyway :)

little boys dam streams, and big boys have their fun with lowering the water, drainage, pumps and hoses. An interesting construction phase for you. Watching when the company does it is not so much fun.

Watching when the company does it isn't much fun.

and I wouldn't have learned nearly as much in the past few weeks. Valuable insights have been gained about soil composition, their interrelations, and everything around it. It’s also kind of fun to grow exactly through such challenges. And by the way, one can finally move heavy machinery again :-D

and I wouldn’t have learned nearly as much in the past weeks. Valuable insights about soil composition, their connections, and all the surrounding aspects have been gained. It’s also somehow fun to grow through exactly such challenges. And by the way, one can finally move heavy equipment again :-D

Finally arrived at house construction! Exactly right. I want to give you one more tip. However, I don’t know your soil composition nor the water conditions. Think carefully about how you want to lay your drain pipes, so that your milling channel doesn’t constantly collapse. But I have no experience in this area either. I only ever see the option with lances.

I want to give you one more hint. But I don’t know your soil conditions or the water situation. Think carefully about how you want to lay your drain pipes, so that your milling trench doesn’t constantly collapse. I have no experience in this area either. I only ever see the option with lances

The collapsing issue is indeed still giving me some headaches. Since we’re doing this as a team of two, laying the pipe simultaneously with the milling progress should be able to prevent a collapse. It will only get difficult if the water washes out the soil too much during milling. But since we have some time before construction starts, in the worst case I would drill 4-6 more shafts and install vertical soakaway shafts. That will cost 2-3k more for machine rental, pumps, and electricity, but it should work then. Something can always happen, a bit of tension is part of it :) *Edit: The lances are a vacuum method (closed water management) used for rather impermeable soils like sand, silt, and clay. Since we have well-permeable soil (lots of gravel), gravity drainage is possible.

Update from 09.05.2022:

This morning the first and so far only offer came in by email. The good thing upfront: the professionals plan the system pretty much exactly as I did without having talked about it beforehand. So that basically confirms my technical design :)

But now the downside: nearly 40k for a really manageable water management system I simply find extortionate. I have to say that clearly. Since I have dealt with the subject more than enough by now and the items in the offer are unambiguous to me, I can only shake my head. They are really trying to line their pockets heavily. I really have to be careful not to comment too emotionally now, but one thing really bothers me: "The wells become the property of the client after construction" means nothing other than: "If the neighboring houses sink into a hole or the street floods, that’s not our business and oh yeah, you also have to take care of the removal yourself or pay us handsomely for it." That’s not exactly inspiring trust in their work. Sure, no one can fully see underground, but if I hire professionals with self-promoted years of experience, in my opinion that’s just weak.

I don’t want to go into individual items further, but if I didn’t trust myself to do this, I would now consider skipping the basement. Because if I also include services that according to the offer must be done “on the client’s side,” I will probably be well above 60k including the wastewater fees. That is completely disproportionate, simply absolutely out of the question. I also think the industry is now seeing its customers flee and is trying to squeeze the lemon as hard as possible out of those who still want to build at this high price level.

Sorry if I got a bit emotional, but that had to be said urgently.