My water well has filled with sediment

[1Mech]

My well is ~120 feet deep. When drilled, about 4 years ago, the driller said it ran 60 GPM with the static water level at 30 feet. The pump was placed at 80 feet and the water tasted wonderful. But now, 4 years later, the water coming out of the faucet looked like root beer a few times and always cloudy. Eventually the flow went way down and took a long time to fill the pressure tank. I called out the people who drilled it, they pulled the pump, only to find the pump stuck in sediment, sand and small rocks. The well itself is only about 40 feet from a spring fed creek, I am not sure why they drilled it so close to the creek, as the driller himself said they often have trouble when close to a creek, this is in the north central Arkansas Ozarks. We have discussed redrilling to clean the sediment out and extending a new casing further down the well bore with a plug hopefully below the point the sediment is entering. Another option is to drill a new well. Have any of you had experience with this sort of thing? Currently I have the pump lying in the creek and using creek water for washing and toilet flushing. The creek is very clear running, so the water actually looks better than what was coming out of the well, but we do bring in city water for drinking.

 

[ponytug]

Gosh, sorry to hear of your issues.

Around here, it is common to run compressed air down the well in a long pipe to clean out a well. I can't comment for your location, but 40' to a stream in a sand aquifer seems close.

To what depth was the well casing run?

To me, the bigger question is where the soil/rocks/sediment came from; did the well driller inspect the bore, looking for collapse(s)? Where does the sediment match the drill record?

Finally, how competent do you believe this driller is? Four years to well failure seems...rather short.

All the best,

Peter

 

[scootr]

I'm in a different area of the country but a 40' well sounds quite shallow. We are closer to 500 ft.
Anyway your water table is high but there is active sediment movement at that depth. I would guess a deeper hole with the pump suspended well above the bottom would solve the problem for x years to come depending on how fast the hole fills with sentiment and how much off the bottom the pump and water line is.

 

[MotorSeven]

60gpm? Sweet Baby Heysoos, that is a lot of pressure. My well is 15gpm and that is considered very good. Anyway, how many feet of casing did they use? It sounds like the un-cased walls have collapsed due to that high pressure.

 

[dodge man]

Normally you are pulling water from an aquifer and the creek shouldn’t affect it. I wonder if a little pressure from the creek is forcing the crap in your well. What to do to fix it? I haven’t a clue. Go with what the well guy suggests along with your own judgement.

 

[steve tym]

Talk to a REPUTABLE (not the cheapest) well driller in your area. Wells are local. Don't take the advice of a guy from NH that knows about wells in his area, but probably not in your area.

 

[steve tym]

Sorry, I was reffering to myself as the guy from NH

 

[Sportsman762]

I am sorry to hear about your problems.

My well is ~120 feet deep. When drilled, about 4 years ago, the driller said it ran 60 GPM with the static water level at 30 feet. The pump was placed at 80 feet

Thanks for the data it gives a better idea of what you have. Most folks are like "I have hole in ground water comes out".

I called out the people who drilled it, they pulled the pump, only to find the pump stuck in sediment, sand and small rocks.

You should not be getting large sediment on a well that is 120' deep with a pump 40' off the bottom and is only 4 years old. What did your well driller state was the reason for the failed well? It would be interesting to hear their thoughts. I can say that one of two things happened, something very weird happened causing the well to fail suddenly or your well driller is incompetent.

We have discussed redrilling to clean the sediment out and extending a new casing further down the well bore with a plug hopefully below the point the sediment is entering. Another option is to drill a new well. Have any of you had experience with this sort of thing?

My comments are going to be general as Steve (who is very experienced in wells) stated it well. Don't take the advice from a guy who did water wells in MN either (me).

Talk to a REPUTABLE (not the cheapest) well driller in your area. Wells are local. Don't take the advice of a guy from NH that knows about wells in his area, but probably not in your area.

Starting with well basics you have one of two types of well:

1. Open Bore Well: the well was drilled and cased down to rock, then the bore (hole) was extended into the rock. Fissures in the rock let the water enter the well to be pumped out.
2. Screened Well: The well was drilled and a screen was inserted out of the bottom of the casing, or slotted casing was put in. The screen size is sized to what the formation is made of. Formations made of course material have course screens, fine formation have fine screens. Below is a screen

You have a few different options, however they depend on how the well was constructed. If it has a slotted casing your pretty much out of luck and a new well is in order as there is no "fix" that I know of.

If the well is screened and the screen was too course then you need to remove the screen and replace it with a finer one. To do this you will need to bail the well.

Around here, it is common to run compressed air down the well in a long pipe to clean out a well. I can't comment for your location, but 40' to a stream in a sand aquifer seems close.

I would not air lift the well as air lifting in a formation that is not rock can result in a giant cavity that will collapse. This well will need to be cleaned with a bailer. A bailer will lift the sediment out leaving a straight hole.

discussed redrilling to clean the sediment out and extending

If it is a plastic casing you should not drill through a plastic casing. The drill rod will rub holes in the plastic casing almost all of the time, normally were the drill stem stabilizer is. If it is a steel casing you can drill through it with out much worry.

If the well is open bore then you could bail it and set a screen. The screen would prevent the well collapse and mostly eliminate the sediment.

I would check with the original driller to see if they would fix this for you. It could be an honest mistake of going with an open bore, not realizing that the well went through a large fissure that had sediment, then the sediment flowed into the well blocking it, or some other issue like that. If they will not fix it for low low cost then "fool me once shame on you fool me twice shame on me".

If you go with another company, call around and talk to lots of folks. You can do a well cheap, but you get what you pay for.

Talk to a REPUTABLE (not the cheapest) well driller in your area.

Keep us posted on this. Good Luck!

 

[1Mech]

Gosh, sorry to hear of your issues.

Around here, it is common to run compressed air down the well in a long pipe to clean out a well. I can't comment for your location, but 40' to a stream in a sand aquifer seems close.

To what depth was the well casing run?

To me, the bigger question is where the soil/rocks/sediment came from; did the well driller inspect the bore, looking for collapse(s)? Where does the sediment match the drill record?

Finally, how competent do you believe this driller is? Four years to well failure seems...rather short.

All the best,

Peter

The casing is to 82 feet as I recall. The driller has been in business a long time and had good reviews, but in this instance, I wonder??

I'm in a different area of the country but a 40' well sounds quite shallow. We are closer to 500 ft.
Anyway your water table is high but there is active sediment movement at that depth. I would guess a deeper hole with the pump suspended well above the bottom would solve the problem for x years to come depending on how fast the hole fills with sentiment and how much off the bottom the pump and water line is.

I am sorry to hear about your problems.

Thanks for the data it gives a better idea of what you have. Most folks are like "I have hole in ground water comes out".

You should not be getting large sediment on a well that is 120' deep with a pump 40' off the bottom and is only 4 years old. What did your well driller state was the reason for the failed well? It would be interesting to hear their thoughts. I can say that one of two things happened, something very weird happened causing the well to fail suddenly or your well driller is incompetent.

My comments are going to be general as Steve (who is very experienced in wells) stated it well. Don't take the advice from a guy who did water wells in MN either (me).


Starting with well basics you have one of two types of well:

1. Open Bore Well: the well was drilled and cased down to rock, then the bore (hole) was extended into the rock. Fissures in the rock let the water enter the well to be pumped out.
2. Screened Well: The well was drilled and a screen was inserted out of the bottom of the casing, or slotted casing was put in. The screen size is sized to what the formation is made of. Formations made of course material have course screens, fine formation have fine screens. Below is a screen

View attachment 4666291

You have a few different options, however they depend on how the well was constructed. If it has a slotted casing your pretty much out of luck and a new well is in order as there is no "fix" that I know of.

If the well is screened and the screen was too course then you need to remove the screen and replace it with a finer one. To do this you will need to bail the well.

I would not air lift the well as air lifting in a formation that is not rock can result in a giant cavity that will collapse. This well will need to be cleaned with a bailer. A bailer will lift the sediment out leaving a straight hole.

If it is a plastic casing you should not drill through a plastic casing. The drill rod will rub holes in the plastic casing almost all of the time, normally were the drill stem stabilizer is. If it is a steel casing you can drill through it with out much worry.

If the well is open bore then you could bail it and set a screen. The screen would prevent the well collapse and mostly eliminate the sediment.

I would check with the original driller to see if they would fix this for you. It could be an honest mistake of going with an open bore, not realizing that the well went through a large fissure that had sediment, then the sediment flowed into the well blocking it, or some other issue like that. If they will not fix it for low low cost then "fool me once shame on you fool me twice shame on me".

If you go with another company, call around and talk to lots of folks. You can do a well cheap, but you get what you pay for.

Keep us posted on this. Good Luck!

When the driller was drilling, he said at the outset, they had a lot of trouble with sand/gravel and originally put down a 8" casing to hold the loose stuff back until they got into rock, then they put in a 6" steel casing. He said they were fighting it from the start. Maybe that was a sign that it wasn't the best location to drill.
I don't know why they picked that particular location. I was in Oklahoma at the time and left the decisions to the "experts".
As of now, they have not really come up with a cause. Once they get the debris out, and water clears up, we have discussed lowering a camera to see at what point the debris is entering and going from there.
I guess this would be considered an open bore well.
In November they tried using a bailer to get the mess out, but it would not go very deep into the gravel, so they gave up on that idea. We are not yet living in the house, still finishing up the inside, but it was providing water to the rv I live in while there.
As far as failing suddenly, it came to a head suddenly, but the water seemed to lose it's clarity soon after I started using it. If I filled a white bucket, the water had a light brownish color maybe within a year after the wells completion. I guess I should have said something sooner.
Thanks for all the info. They are coming to take another look at it later next month, I will see what develops.

 

[Doofy]

Look up "Brumby Pump". Specifically designed to clean out silted bores. Or...you can make your own.

 

[Sportsman762]

they had a lot of trouble with sand/gravel and originally put down a 8" casing to hold the loose stuff back until they got into rock, then they put in a 6" steel casing

That makes sense. I have only been in the Harrison area a few times during my 2 year stint in AR and I was not drilling at the time. I am guessing you have granite or some other hard igneous rock if I remember right. Very pretty area, reminded me of where I grew up in OH, except we had sandstone instead of the hard rock you have. You have a loose formation of gravel above the rock. To drill rock you have to use down hole hammers which run off of air. They drilled down with a tricone through the loose formation to the rock formation, set 8" working casing then switched the rig over to air and drilled down through the 8". Once they had an open bore they drove 6" into the hole sealing it to the rock and pulled the 8". It sounds like good construction to me. However they might not have sealed up the 6" into the rock, or there is a fissure in the rock letting the sediment in. Without being a local and knowing the geography I am just guessing. (don't take anything I say to heart as I have no clue about hard rock drilling).

In November they tried using a bailer to get the mess out, but it would not go very deep into the gravel, so they gave up on that idea.

That sounds like a good try. Most modern drillers do not have the heavy cable tool bailers that could penetrate a gravel mess and pump hoists are not as good as a cable rig for baling.

They are coming to take another look at it later next month, I will see what develops.

Glad to hear that they are working with you. Its hard to say if the issue is their fault or not. Without using gamma loggers, calipers and other very expensive equipment its hard to tell whats going on in a well so errors can happen. The oilfield folks have all the cool toys, water well drillers are not charging the hundreds of thousands it takes to pay for a wire line van to show up to check the well construction. We made it a point to be very friendly with the state geological survey and the state health department as they both had some cool toys and if you sweet talked them they would come out and log a well when we had concerns.

Sounds like you should keep working with the crew if they are going to try to make it right. I suspect the solution will cost you and the driller some money. Keep us posted, this is an interesting issue.

 

[1Mech]

According to USGS, this is what lies beneath my property, mostly a form of limestone.

Source Geology
"Unit/Name: Ocjc Cotter and Jeferson City Dolomites
Description: Cotter Dolomite---Dolostone of predominantly two types: a fine-grained, argillaceous, earthy textured, relatively soft, white to buff or gray dolostone called "cotton rock," and a more massive, medium-grained, gray dolostone that weathers to a somewhat hackly surface texture and becomes dark on exposure. Contains chert, some minor beds of greenish shale, and occasional thin interbedded sandstone. Thickness is about 340 feet in the vicinity of Cotter but may range up to 500 feet thick in places. Jefferson City Dolomite---Light- to dark-tan, fine-grained, crystalline dolostone and considerable chert with some rare thin beds of sandstone, shale, and oolite"

 

[ponytug]

According to USGS, this is what lies beneath my property, mostly a form of limestone.

Source Geology
"Unit/Name: Ocjc Cotter and Jeferson City Dolomites
Description: Cotter Dolomite---Dolostone of predominantly two types: a fine-grained, argillaceous, earthy textured, relatively soft, white to buff or gray dolostone called "cotton rock," and a more massive, medium-grained, gray dolostone that weathers to a somewhat hackly surface texture and becomes dark on exposure. Contains chert, some minor beds of greenish shale, and occasional thin interbedded sandstone. Thickness is about 340 feet in the vicinity of Cotter but may range up to 500 feet thick in places. Jefferson City Dolomite---Light- to dark-tan, fine-grained, crystalline dolostone and considerable chert with some rare thin beds of sandstone, shale, and oolite"

That sounds great, but it doesn't sound as if it matches what is coming up your well by color alone.

Good luck on getting it fixed. I thought that @Sportsman762 has a nice summary of the possible things going on.

All the best, Peter

 

[steve tym]

Dirty water calls can be the hardest to troubleshoot.

 

[RobertEH]

I had a similar issue with our well at the last place we lived. The well was about 75 yards from a salmon stream as the crow flies (but the area the well was dug at was a good 100 feet higher than the elevation of the creek-fi that makes sense...). I want to say the well was about 350 feet deep with the pump sitting about 100 feet off the bottom. We were getting really really bad silt/fine black sand. There was a sock filter set up and it would pack the filter with silt in about 1 day when things were bad. The silt got into the washing machine and gummed up the works there too. It would show up in our drinking water. It was terrible.

Had a well guy come out and look at it. He tried to pull the pump, but it was mired down in sand so bad he almost could not get it out. He said he had to run the pump to loosen the sand around it so he could extract it.

They did a refurbish on the well and pulled out 100 feet of sludge from the bore hole. He then looked at the filed info on the well when it was originally built, and he found that the screens had been installed to 200 feet (or something like that). So the pump had been sitting below the screens!! Anyway, he raised it until it was no longer below the screens. We sold the house about 2 years after this work was done, but our pressure increased and the silt/sand was 100% gone. Not sure how long it will take to fill back in, but getting it fixed was a game changer.