water table info for a shallow sandpoint driven well

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iwantawell

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No local well drillers around can give any info on what to expect on depths for these types of wells.

ARCGIS has some interesting online maps, and their maps for "Water Table Depth - Annual - Minimum" suggest that my water table is approx 100cm below earth's surface. I dont see how this is possible. In fact I think their maps are completely flawed - lots of central alabama is listed as water table from 0 - 25cm deep.

Are there any other sources I can go to in order to see if a sandpoint is appropriate for my area? I have nice prairie soil, shouldnt be too hard to dig at all. Should I just go down to 25ft and if it produces nothing just write it off?

Im in central Alabama, in a town particularly proud of its wells, (but not sure if they are aquifiers or shallows) at that.
 

Reach4

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I would ask the neighbors. I suggest asking in feet rather than cm.
 

iwantawell

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Its all aquafier 100ft+ wells around here. Local drillers dontvknow or wont say. I guess if word spread of alternatives they could lose out
 

TJanak

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The parts of Alabama I've traveled have large areas of Alfisols and/or similar, which are comprised of a lighter, sandier soil over heavier, clay subsoils. This is in large part due to your high rainfall environment over thousands of years leaching clay minerals from the surface horizons to the subsoils. When this is the case and you receive a large amount of rain, water cannot percolate through the clay subsoils fast enough, creating a perched water table for periods of the year. This is what the soil maps you are reading are describing. The estimated average minimum depth to this perched water table may be 25 cm or whatever number the maps are giving. And although water technically could be pumped from this perched table, it's not something feasible nor something a person would want to do.

So no, the maps aren't as flawed as you were thinking.
 

iwantawell

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very interesting, thanks for this explanation! so do i just auger and then pile drive to 25 ft and hope for the best? or would I just not be able to expect any water bearing gravel/sand layer down there?
 

LLigetfa

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I don't buy into your conspiracy theory WRT the drillers. If there was viable water without going 100 feet, I doubt your neighbors would all have 100 foot deep wells.

See if you can get a report on some of those wells. The report should include the formation.
 

iwantawell

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Augering now. First 7 ft was super easy, 30 min. Easy topsoil. Then hit clay and this is very tough work. Really hard clay. Pulling up what looks like really big pencil shavings 10 ft of this clay so far and taking a break. Getting a little worried that ill suffer through just clay till 25 ft deep. That will suck. This is very hard. Even have a good helper and its still long and hard. One layer of the clay was all white for nearly a foot now its back to red and white again

clear.gif
 

DonL

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If you get down to 20 feet and see no sand or water, it may be a lost cause.

Don't give up yet. Our land here is just like what you are dealing with.

You can always install a well casing if you hit water, to keep the clay from hosing you.

You may need a jet or sub pump.


A am no pro tho, Just been there done that.
 

iwantawell

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Augering now. First 7 ft was super easy, 30 min. Easy topsoil. Then hit clay and this is very tough work. Really hard clay. Pulling up what looks like really big pencil shavings 10 ft of this clay so far and taking a break. Getting a little worried that ill suffer through just clay till 25 ft deep. That will suck. This is very hard. Even have a good helper and its still long and hard. One layer of the clay was all white for nearly a foot now its back to red and white again. Time for a break.

(45 min break)


So! After the short break, the first auger payload had a bit of very wet, muddy clay on the top! So must have had some seepage during the break. We continued to 17 ft and had much less compacted clay. Still dry but more sandy i guess. At this point we are out of auger extensios and had to go to lowes to get more auger extensions.

(1.5 hrs break)

Water at bottom!! Guess had some nice seepage. Continued auger, get to 21 ft and the payload we pull up is very very heavy wet wet mud. i believe we could still auger deeper, but the auger plus payload to pull up is very heavy and were kind of getting tired. Its game time anyways (WAR EAGLE) so we put the sandpoint and 20ft of water pipe in to measure level. There was 2 ft of water at bottom. Will check later to see if more seepage gets deeper at halftime.

(~ 1 hr break)

The water level was about 15 ft down from surface of ground. I have 2 10ft extensions + 3ft sandpoint. there is almost 2ft pipe sticking up out of ground so it looks like the sandpoint has about 2 ft of water over it.

But its all wet mud at the very bottom, thats all the auger was pulling up when we stopped. This is all 1.25" galv steel. Should I put on the extra 6ft extension and see if I can drive it till i have about 3 ft of pipe sticking up out of ground?
 

Reach4

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I have never used a sand point, but unless you happened drive it into sand or gravel, I think you would do better leaving the point at the bottom of the hole, and pouring sand or gravel in the hole up to where the water started. Even then, I am thinking you will suck it dry pretty quickly. I figure that driving it into more clay would just seal it up.
 

LLigetfa

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A small augered hole in clay that only seeps in slowly will never work.

You must be a glutton for punishment. The washdown method is a lot less work unless you intended to put down a larger casing than 2 inch. I helped my father put down 120 feet of 2 inch casing using the washdown method.

If and when you do get through all that clay with your oversized augered hole, how do you intend to seal the casing to keep surface contaminants from seeping down the annular space?
 

iwantawell

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A small augered hole in clay that only seeps in slowly will never work.

You must be a glutton for punishment. The washdown method is a lot less work unless you intended to put down a larger casing than 2 inch. I helped my father put down 120 feet of 2 inch casing using the washdown method.

If and when you do get through all that clay with your oversized augered hole, how do you intend to seal the casing to keep surface contaminants from seeping down the annular space?

well i wanted practice on doing it w/o a source of water for washdown. was planning on using a 6" PVC sewer pipe to encapsulate the 1.25" pipe.

really not sure what to do now... will call the state geologist again, hes expecting to hear my results. hes actually done a few sandpoint wells himself, in FL.
 

DonL

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really not sure what to do now... will call the state geologist again, hes expecting to hear my results. hes actually done a few sandpoint wells himself, in FL.


Move to Florida where they have sand ?

Good Luck on your project.
 

LLigetfa

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My father had a shallow well that did not produce enough water for domestic use and the livestock. I had to haul water from a creek a half mile away. We captured and reused most of the water for drilling. Most of the 120 feet was all clay until we hit hardpan which was tough to get through. The water was after the hardpan.

Tripping out that much drill steel by hand will grow old fast. Look into cable tool drilling instead.
 

iwantawell

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well my parents are 1 county over and they have a culvert well down to 70ft. their water is really irony though. I guess worst case, I could salvage something out of this project if i wanted to pull all my 1.25" stuff up and sink some 2" pipe with one of these cable drilling tools and use a 2" inpipe pump?
 

DonL

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well my parents are 1 county over and they have a culvert well down to 70ft. their water is really irony though. I guess worst case, I could salvage something out of this project if i wanted to pull all my 1.25" stuff up and sink some 2" pipe with one of these cable drilling tools and use a 2" inpipe pump?


If it is 2 inch you can use a Packer and a Jet pump.
 

iwantawell

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oh and my uncle who was helping me swears the last 2 auger payloads we had looked less and less clay and more sandy. but I dont think so. it just looked like wet wet mud to me. i think possibly he thought it was becoming less clay'ey because it was just so wet. but who really knows we really dont know wtf we are doing here, or what to look for.
 

DonL

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oh and my uncle who was helping me swears the last 2 auger payloads we had looked less and less clay and more sandy. but I dont think so. it just looked like wet wet mud to me. i think possibly he thought it was becoming less clay'ey because it was just so wet. but who really knows we really dont know wtf we are doing here, or what to look for.

Normally if a Hole will not take water, You will not get any.

Drink another Beer and chill awhile.
 

LLigetfa

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If you switch to cable tool drilling, then stay with at least a 5 or 6 inch bore so that it can take a standard sub.
 
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