Augering a sand point well - Brilliant or Dumb?

Hello friends, I'm going to install a sand point well when I build my greenhouse this summer.  I will put a pitcher pump on the well and probably also a shallow well pump.  I believe the water table is about 10-12 feet down and it is primarily sand or sandy clay between the surface and the water.  There might be a hidden boulder though.

Option 1:  Just drive a point and hope for the best.
Option 2:  Auger a 6" hole with my post hole auger until I hit water.  This would probably take about 20 minutes based on prior holes I've augered.  Hopefully the sand will hold together enough that I can auger 4'+ down into the water table.  Then drop a 4" PVC pipe down into the well to act as a casing.  Then assemble a sand point well and drop it down the hole.  If it ever plugs up I can just drop a new one down the hole.
Option 3:  Auger until I hit water.  Assuming the hole collapses or I can't pull out the muddy material and I can't auger deeper, install the 4" PVC well casing.  Assemble the sand point and drive it 4+ feet down into the water table.  Then if the point ever plugs I might be able to pull it out.  If not I can drop a new one next to it and drive it.
Option 4: Same as option 2 but I just put a filter of some sort and a foot valve on the end of a water line and set it down in the water (no fancy point).

Am I over thinking this?  Are there other options?  I think this is a simple well driving situation, I'm just trying to leave myself as many options as I can.  And I own the auger already.

There are some rather interesting videos on YouTube you might take a look at.
One in particular where some people in Africa use a bucket of water and a one way valve on a piece of plastic pipe.and a slightly larger pipe to stop the sides of the hole caving in while they make the well.

I believe they first dig a hole and then put the casing in. A one way valve is built into the plunger tip of the long piece of plastic. The casing the has water poured into it, with a blunging motion, they are then able to use the downward pressure and the water motion up the tube to remove the sand from inside the casing. After a while they remove the plunger pipe and bash the casing down with a hammer and a large piece of wood to protect the casing. Then they start again by adding more water and re plunging. This continues until they reach the required depth.

I hope you can find the video on YouTube. It's much clearer than my explanation...

If I get chance to look for it tomorrow I'll try and add a link here.



found it.  :)

Regards Phil.

Another possible idea.

Go to a plumbing supply store (Not HD/Lowes) and buy a 20ft long piece of 4" PVC.  Cut 4-5 notches in one end so it looks like the tower on a castle.

Augur the hole as deep as you can, then drop the PVC in notched end down. Rotate the PVC back and forth while pushing down so the notches cut into the earth until it stops going down. This won't cut through rock, but should work just dandy through sand and clay.
If you're lucky it might end up drilling down as far as you want it, I think you want it at least 5-10 feet below the water line.   Drop a hose all the way down the PVC and turn on the water, this should force some of the sand and dirt out the top. Go back to rotating the PVC to see if you can force it down any further.
Another option you can try, if you have a high volume air compressor, drop a weighted airline down to the bottom and turn on the air.  This should form a crude "bubble lift" pump which should cary a bunch of the water and some sand/dirt up and out.

Ideally you'll get the PVC all the way down until only a little bit is sticking out.  Now you can drop a well pipe down the hole with your sand point attached and won't have to drive it in, this way if it plugs up you should be able to just pull it all back out and clean of the sand point and then use it again.

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Thanks for the link Phil, that makes more sense.  I think I might do a combination of all of this.  

I can auger the hole much faster than what they were doing, at least down to the water table.  Once down there, if I can keep augering, I'm set.  If not I can drop down a well casing with slots in it and then do their system for the next 4 feet.  Maybe I could even get their initial method of the pipe to collect a cylinder of sand to work.  If not, the check valve system.

Thanks for the ideas Peter!  My air compressor isn't that beefy and I suspect that a hose wouldn't push enough sand up out of the hole.  Maybe it would but I'm not seeing it in my brain.  I wonder how much lift my shop vac would have.....  

I think I have it from here.  Thanks gentlemen!

Your welcome, let us know how it works out.

Phil

Hi Mike.

Is there something about the sand point method that isn't good enough? What are the benefits as you see them to the other methods?

-CK

The sand point method is pretty good, and in my case would very likely work out just fine.  The issues as I see them are:

If I hit a rock about 8 feet down, I believe I'd have to abandon the point and piping, buy another point and try in another spot.  
If the point plugs up after 10 years I have to buy another one and drive a new well

With my proposal I can avoid the rock issue by just auguring another free hole.  And if I can auger down into the water table, I don't even need a point, just a filtered intake and a foot valve at the end of a pipe.  

Ok, I have an update.  I augered down about 12 feet.  It was topsoil for the first 18", then sand until 7 feet, then clayey sand that started to get moist for a few more feet, then wet clay.  Once I got to 12' I was pulling up wet clay that would refill the hole.  So I couldn't go any deeper.  So much for using the auger to get down into the water table.

I forgot about all the wonderful suggestions above and just changed over to assembling a sandpoint.  I figured all I had to do was drive it down 5 feet and I was done.  It pushed down into the clay about two feet.  Then I started pounding on the drive cap.  I had tightened the other fittings with pipe tape and two pipe wrenches.  For those familiar with the building trades, I "spot torqued" them.  For those unfamiliar, I tightened them until I saw spots.  For the drive cap I skipped the pipe tape and only hand tightened it.

After driving a bit I found the pipe was shaking around too much so I backfilled the augered hole most of the ways back up to the surface.  I was using a sledge hammer to drive.  After a dozen hits I'd snug the pipe cap back tight again (by hand).  I drove about 18" before the drive cap flew off along with three threads of the pipe it had been attached to.

Question #1:  Did I mess up by not tightening the drive cap on really tight?  Is that why the pipe broke?

Luckily I was able to unscrew the last pipe (coupling was 18" below grade) and replace it with a good pipe.  I measured 6' of water at the bottom of the pipe (Yay!).  So I hooked up a brand spanking new pitcher pump.  I poured some water in the top of the pitcher pump like the directions say but it only accepted about a quart or two of water (seems like it should have taken much more).  Then I pumped and after the first encouraging slush of water, it started pulling hard and didn't move any more water.  I heard a small air leak and traced it down to the new leather seal.  I let is soak up water for an hour and tried again.  This time no air leak but no water.

Question #2:  If I failed to fill the pipe with water, is that why the pitcher pump is just sucking a vacuum?  

Question #3:  What else am I missing?  Maybe the 6' of water is just slowly filtering in through the clay and that's why it isn't able to suck any up.  So I should drive it deeper?

You'll need to get past the clay and into a sand / gravel vain. The clay will just build up around your point and block it.

Thanks Phil, I think I'm through the clay based on my findings this morning.  I realized that a couple of quarts is not nearly enough water to fill the pipe (yesterday's findings).  So I ran 300' of hose out there from the house and took the pitcher pump off of its base.  There was still 6' of water in the bottom of the pipe so the water level is about 9' underground.  My pipe is sticking out of the ground about 4' so a total of 13' of empty pipe.   I ran hose water down the pipe for over a minute.  Weird, should have filled by then...  So I quickly put the flapper on and heard the suction of the water trying to get back down to level.  After "burping" it a couple times, it stopped sucking.

My takeaway from that is that I'm in the water table and the water is freely available.  So much so that it drains down into the water table faster than my tap water (through 4 hoses and a spray nozzle) can supply it.  Yay, I think that's a good sign.

Now, how do I prime the pump to get the water out?  The directions on the pump say to lift the handle and pour water in the top and then pump.  That merely pumps out the quart of water and then it's just sucking against the dead head.

I then sprayed the hose in the top of the pump while pumping (slow, fast, some of both) for 5 minutes.  It gurgled as the pump handle went up and pumped out the water I was adding as the handle went down.  I'm guessing the theory is that the new water I'm adding is supposed to sneak past the leather flapper when it is lifted, replacing some of the air in the casing with the new water.

What am I doing wrong now?  Would a tiny air leak in a fitting cause this?  Am I giving up too soon and I just need to keep pumping and spraying water in there?  I can't see how to add water to the pipe faster than it is being drained down.

Maybe I could put a "tee" under the pump and plumb the garden hose right into the well casing with a valve.  Turn on the house water and force it into the well casing with the pitcher pump removed.  Get the flow right so that water is slowly coming out of the casing and then reassemble the pump.  Then if I need to drain the well for frost I can just open that valve.

I dunno, any more thoughts out there?  

I am augering a 3 inch hole and am about 17 ft down still into clay .i got about 9 ft of muddy water .i had about 7 ft of sand and reast of it caly .should i keep going or give up thanks

barry Hefford wrote:I am augering a 3 inch hole and am about 17 ft down still into clay .i got about 9 ft of muddy water .i had about 7 ft of sand and reast of it caly .should i keep going or give up thanks

Was the sand wet/in water? By the way, I've read of 3 inch diameter Grundfos electric well pumps. I don't know about whether to keep at it or not, but hope to learn, as I am considering doing something similar.

To answer your question, I would continue for at least 4 or 5 feet.  But that depends somewhat on how much work this represents. That said, have you pumped the hole dry to see how fast it will refill and the quality of water it refills with? Another piece of the answer lies in the question of what you are planning on using the water for?  Is it for household use, livestock, garden, or some combination?

I found a neat resource; a Massachusetts guidebook for private wells. It mentions driving a wellscreen into place shielded by an oversized casing: page 27 at: https://www.mass.gov/files/documents/2018/07/27/prwellgd.pdf

After driving into place, the wellscreen is exposed to the groundwater by drawing back up the oversized casing. This protects the screen during driving. I haven't done it or talked with anyone who has, though.

Here's a 4 inch auger attached to the shortest one of three extensions made locally, with handle attached. You can see water in the hole - it's been wet lately. That slows getting the dirt from the hole - it slumps off the auger before surfacing. I hope to hit a sand or gravel layer soon, to ease accessing significant water in dry periods. Then I intend to put in a four inch well screen and casing.
The location is a little plateau part-way up a rocky ridge.

To all who have been halted in a collapsing clay layer- look at bentonite as a stabilizer. I’m messing around with it now and it really helps.

Has anyone tried casing a 4" hole for sand point in Central minnesota if so what were the results of the whole project? Jeremy.westcoastrodents1@gmail.com

Mixed results with a sand point 30 miles south of Walker off of 371.  None with 4”.   Hit water at 5’ in one case with 2” sand point.   Weird, but the flow stayed good and the water tested good.   Drove another well some 5 miles to the west of there.  Put 20 ft of pipe in with no results.  I suspect we hit rock.

I'm looking to install a sand point well. The instructions I found are clear on the mechanics of driving it, but the part about what pipe to use and when to stop driving seem to assume the property is on an actual ant farm and you have access to the extremal view as in 'stop when your tip has penetrated the water level as shown in this side view'. Will I be able to test for the water level by removing the drive cap and dropping rope or something down the pipe, then resume driving if needed?

I have encountered several approaches in my limited experience.  In one case, the pipe suddenly went down easier than it had been.  It was also possible to tap the pipe with a hammer and it hear the water. I have no idea if this usual.

Every time you add a new chunk of pipe (5'), drop a weighted string down and see if it gets wet.  If you're really interested in finding water, take the drive cap off halfway between pipe additions to check at every 2.5'.

When I was looking, pipe came in 10' or 3' sections (galvanized steel). They say you can use smaller pipe (1.25") if the table is less than 25' down, but need 2" if lower. In my mostly sandy soil gently sloping to an open running creek, should I expect the water table to climb a bit going away from the creek? IE if i drive the well where I am less than 25' above the creek level, should I strike water less than 25' down? It's been way too long since I had my physical geography class...

I think I used 1.25" and they had 5' lengths for that.  Maybe that's where all my problems came from.....

Mike, did you ever try a casing in any of your fruitless well ventures? Is it supposed to help with making the well work or is it just to make it easier to reclaim the sand point in case of a failed attempt?

I believe the idea is that if you auger down to wet enough dirt, you can drop a 4-6" pipe down there to hold back the dirt and let water accumulate.  Then you can just put a well pipe down to the bottom with a foot valve (check valve) on it to suck in the water.  I don't think you even need a sand point at that point...

I didn't case my attempts because I never got into wet enough dirt that I thought the casing would hold enough water to matter.

How do you prevent the check valve getting sand in it and staying open?

Good question...  There's usually a screen on the foot valve to protect it.  Plus, I'd think that moving water would keep sucking the sand in so it can't stay in the way of the flapper.  Maybe.

Here's more info: https://inspectapedia.com/water/Well_Pipe_Foot_Valve.php