Sand Point Wells

[KDM]

Thinking of driving in a sand point well to provide water to the gardens/trees/critters/etc instead of running 2.34 miles of hoses all over Fathers creation like I have been, but have absolutely no experience with them. Anyone have any insights, advice, horror stories, anecdotes, or have put one in themselves and would like to share some thoughts on how it went, did it work, do you still use it, and a would you do it again sort of thing, I'd appreciate it. My water table is about 15 ft down so pounding one down to depth should work assuming I can avoid rocks. Thanks in advance.

 

[Davy Crockett]

I'm looking at doing this too. I've watched videos and it looks like it can play out a good man. If I had flat ground I'd probably try to hire a utility company pole truck to dig as deep as they can but that's not an option where I want the well. Good luck and keep us posted.

 

[Allen]

So long as you don't have a clay layer that can smear the screen they work pretty decently if you have reasonable expectations for production. You can get pretty much anything you need for this project at Menards, I think. Not sure if I've ever seen the drive head there.

I've never actually installed a production well with them, but have used them for research a number of times to collect water samples.

I'd probably avoid using the plastic ones to get to 15 ft. If your water table is at 15 ft, you will want to get several feet deeper, like around 20-22 ft. Dissolved oxygen falls very quickly once you are below the water table, but you really don't want to be pulling dissolved oxygen rich water into a well screen. That leads to bio fouling of the well screen, which isn't the end of the world but can be really annoying to have to keep cleaning. Also, any buildings or trees this water contacts will very likely develop an iron coloration to it. Dissolved iron and manganese quickly oxidize when exposed to the atmosphere, take a drive around Fox Island here in Bismarck and you will see what I am talking about.

One thing to keep in mind is that installing a well of any kind does not equate to "free" water. Lifting water is expensive, if you use this for gardening, trees, etc there will be a noticeable bump up in your electric bill.

If you do get the screen below the water table and you can't readily get water from the thing, it likely developed a clay smear over the screen. I've run across this a number of times. You can pull a sand point well using a couple of handyman jacks. Just wrap a chain around the steel pipe a couple of times and then over the jaw of the jack. Not exactly a finesse way of doing it, but it does work pretty well.


Amazon product

Don't use a hammer as shown in the above Amazon post, use a heavy fence post driver. You'll be there a month of Sundays using a stupid hammer, not to mention the risk of messing up your pipe and drive head by a poorly aimed swing at a moving target.

Good luck!

 

[Allen]

One last thing. There is a limit to how deep one can go and pull water with a suction pump. In theory, you can pull water from a standing water surface to a depth of about 33.9 ft. In reality, that wouldn't produce much water because eventually you would cause the water to boil when attempting to pull it up from much more than about 25 ft. If your pump is capable of producing that much vacuum, it can be very hard on the screen, pump, etc. Remember, it doesn't matter how deep the well is screened, this part is all about transmissivity of the geologic medium and the depth to the standing water level in the sand point.

Basically, if I were in your shoes I would aim for a total depth of 23 ft, this would put the standard 3 ft screen at a depth of 20-23 ft. If your water table is indeed at 15 feet, that should suffice to operate a sand point if you have good sand and gravel. Once you install the screen, wait a few hours and figure out how to measure the water surface in the well casing. One trick I have used is a weighted, narrow bobber and a fishing rod. You drop the bobber down inside the pipe and you should be able to feel when the bobber hits the water.

Using the above style, you would want to also tie the string to the top of the bobber. Or tape the string to the bobber. I have faith that you will figure it out. You just wouldn't want to be pulling on the bottom of the bobber, or there's a chance it will get stuck as it turns sideways when you try to pull it back out.

If you can't get production at that screened interval, try driving it deeper to see if you can get into a cleaner sand/gravel layer. The only limitation here is how deep you can physically drive the sand point. There are some nuances to this, but the point here is that even if the water table is at 15 feet, that doesn't mean the geologic medium is permeable enough to produce the pumping rates you desire. That clay smear on the screen is real in some areas, and obviously it's very difficult to install a production well in a clay rich layer.

Fun project!