Some clarification concerning last night’s info bleg post…

I got busy early this morning and have been away from the cabin from Morning Walkie until now, on dog- and laundry-related chores. Came back to a whole bunch of interesting comments concerning drainage. Alas, I didn’t make clear, for the benefit of those commenters unfamiliar with Ian’s Cave, the nature of the structure. Ordinary landscaping ameliorations aren’t going to be of any use here. Allow me to clarify…


This is Ian’s Cave. We built it in 2009. It’s a domed steel framework covered with mesh and burlap and a heartbreaking amount of rebar, and then heavily sprayed with Shotcrete and buried in sand.


That retaining wall between the Cave and the powershed is about eight feet tall. Before we backfilled it, that wall was as tall on the back as it is in front. See that discolored spot in the middle of the wall? There was a spigot on that spot until the (almost explosive) beginning of the 2021 Monsoon, when the area around it began gushing water. Please don’t ask why. Very shortly afterward the Cave developed a serious electrical short on that side of the dome, undoubtedly caused by water incursion. That’s the same side where I’m getting percolation through the floor right now.


This is the rear of the Cave, taken from the driveway that’s a little higher on the ridge we dug out to make the foundation. As you see we made a very serious mistake in leaving a dip between the ridge and the Cave.

On the right side of the structure, facing the front, water cut a fairly impressive gully…


…which in hindsight might actually be a good thing because that gully directs water away from the structure. On the other side, the side with the retaining wall where I’m having water problems, there’s just a dip filled with soft sand.

And I think that’s where my trouble is coming from. Instead of being directed away, water is trickling down onto and under the dome. Obviously, in hindsight, we made some serious mistakes. I don’t see any practical way to fix those problems without spending huge amounts of money which Ian has already said isn’t going to happen. So I need to find a way to deal with the results of those mistakes, and that’s why I’m not interested in fixing the drainage problem: I’m interested in installing a sump so I can collect the water and pump it in a safer direction.

About Joel

You shouldn't ask these questions of a paranoid recluse, you know.
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10 Responses to Some clarification concerning last night’s info bleg post…

  1. The Neon Madman says:

    In that case, I’d put a drywall in the ditch, and pump the water out from there. Just have to watch for when it freezes and shut off the pump. Would mostly take a backhoe and a yard of rock, though.

  2. Ben says:

    Drywall=Drywell?

    Now you are thinking!

    (Just thinking out loud here). Is there any chance that a WellPoint driven just below the edge of the slab would do about the same thing, only without the backhoe?

  3. The Neon Madman says:

    Yes, drywall = drywell. Damn autocucumber.

  4. Malatrope says:

    Is there any way to create a French drain down the side without the water gully? You may not have left a swale, but one might be made.

  5. Joel says:

    Is there any chance that a WellPoint driven just below the edge of the slab would do about the same thing, only without the backhoe?

    Say, that’s an interesting question. It would be incredibly easy to drive a point in that fill. Not sure whether it would do any good, though. Like, how to get a pump to know when there was water in the pipe.

  6. Joel says:

    Is there any way to create a French drain down the side without the water gully?

    Cover the whole thing with rubber fabric, maybe. Like how we waterproofed the powershed roof.

  7. Bartholomew says:

    Random thought – There is, IIRC, a Neighborhood Tractor With Backhoe; does that tractor have a PTO? If so, does anyone have a post hole auger system for it, or could one be rented for a reasonable sum (even from the Big City 50 miles away) ?

    I’m thinking a 4″ (or 6″) auger with extensions to go *really* deep to install a “pump access point” wherever the most likely pump-out point may be. Ideally, a well drilling rig could do it but that’s Big Bucks and access to the house, and the right spot close to it, may be impossible. I’ve done 12-14 foot 12″ holes with a tractor, post hole auger and extensions and while it’s a First Class Grade A PITA that requires at least 2 people, preferably 3, with experience at it, it’s achievable.

    I also wonder if there is, semi-locally, a small drilling rig; I’ve seen a couple on 24-28 ft truck chassis in midwest farm country, primarily for ~100-150 ft irrigation wells. They cannot do what a full rig can, but you’re not looking to go down 800+ feet for a well here.

    There’s also a mini-boom in the ground-coupled heat pump business; those outfits have small drilling rigs – 20-24 ft trucks – that can get in back yards and other tight spaces and can go 300-500 feet with the smaller diameter wells suitable for ground coupled heat pumps. No clue if there are any in AZ or what it might cost to get one to do a 25-40 ft 6-8″ hole for you.

  8. Bartholomew says:

    Another thought – utilities, and utility contractors, routinely place poles 8-12 ft deep and have 9-16″ truck-mounted augers to do it with. Access would be an issue, but it’s still in the 20-24 ft truck range.

  9. Biba says:

    French drain would be worth a try…

  10. Goober says:

    I agree that it’s a grading issue. That low spot between the structures is your problem. Dig out the low spot, put a sump in it, and dig a gravity french drain between the structures that daylights through the retaining wall. No sump pump needed. Some digging, sure, but it shouldn’t be terrible. Just put a manhole cover over the sump and be done with it. Probably fix it forever. Water is just looking for the fastest way down. Provide it a faster way down. Yeah, you’ll have a pipe coming out of the wall (might I suggest that discolored spot is a perfect location for it) but who cares?

To the stake with the heretic!