Digging a well

[TheDreamer]

Hello,

Has anyone ever dug a well? I've been looking at digging a well in the back garden, the water table is only about 10 ft down so not too far and I was wondering if digging a well is a feasible idea. Never done it, and once started and the back goes I might regret it, but I would like to know if anyone has any experience of digging one?

Are there any legal issues that have to be looked at first? What are the things to look out in the construction of? Any good books on the subject that are worth reading first.

Any advice appreciated.

Thanks

Mark

[Meekle]

why are yo udigging a well? is it for crop watering and livestock, or is it for you to drink? the reason i ask is that if you extract water (once you have permission from the local water authority) for drinking, it must pass through several filters and sterilising agents before it is certified safe to drink.

when digging a well, remember that the pressure from the ground heave (i.e the ground trying to close up the hole again) at that depth will be immense. you would need to line the well walls with a circular ring of heavy stone or better still, get some caison rings from the local builders merchant and line the shaft with that.

personally, if you wish to extract the water (after jumping through hoops to get permission to do so), i would sink a bore hole rather than a well. its a small diameter pipe sunk into the ground which is ideal for extracting the water as it can be connected to a pumping system.

Digging a shaft, you would need to have several people on site at all times incase of wall collapse and you would also need a confined spaces awareness certificate to satisfy the HSE before you under took such work. Not to mention that Building Control will want in on the act too to charge a fee to look down your well.

if you are really serious aout doing it, i would part with cold hard cash to a contractor and let them deal with everyone and have the hassle!

[Meekle]

Dont wish to put a downer on the idea, but just thinking out loud of any obstacles in your way before you commit too much time and money into the project. if you can work around the obstacles then fantastic, as then you will be able to draw whatever water you need without paying money to a wasteful organisation such as Severn Trent.

These guys are trying to tell us not to waste water, and yet they lose billions of litres a week through antique pipework. If they were to sort out their netwrok there would be a good chance that all that water wouldnt be lost and out bills come down???

[Editor Paul]

There's a lot of literature on sinking a bore hole and in HF some time ago we did a piece on making a concrete reservoir for a borehole.

[TheDreamer]

Thanks for all your advice. I did think there would be building control involved but wasn't sure. The water would be for watering the garden only, so filtering would not be so important.

I have considered a borehole and in fact I did put down one on my old allotment near the Norfolk Broads, the water table was only at about 8 or 9 feet and I had a corer built with what looked like a little boat propellor on the end, it took a while but I was able to get down to about 12 ft, hit water OK, I lined the hole with a 4 inch drain pipe with holes drilled in. The major snag was the pump I was using couldn't lift the water up, and I had to create a two stage pump system that produced a trickle !! Though because the bottom of the hole was not that deep it eventually turned to mud and then the pump simply clogged up very quickly.

The other reason for the well would be one of increasing the value of the house, our long term 5 to 6 year plan is to move to a larger plot of land, so this is an interim move until kids grow up and move on, I just thought that a genuine useable well in the back garden would be seen as a positive benefit to the property.

I like the idea of the concrete rings, but did not realise they were readily available. I'll have to check etc, but by using them it would stop the risk of cave in - placing one on top of the other, then dig from under the bottom one they would slowly sink down, at least in theory.

Anyway appreciate the ideas and advice will keep you posted if I do make an attempt. Thanks

Mark

[Meekle]

hiya mark,

what you are suggesting there is sinking a caison unit. You are also suggesting a technique known as pipe jacking, although traditional pipe jacking is done horizontally, not vertically.

In sinking the shaft in the way you suggest, you need to be very careful to extract the spoil equally around the ring otherwise it will sink unevenly and you could end up with a curved well!

to sink a shaft this way, your bottom ring would be a sacrificial "blade ring" with a tapered edge to aid cutting through the soil. you may need to lubricate the rings to assist their path through the soil. The best way to do this is by injecting bentonite clay through grouting holes in the rings. This clay will flow through the grout holes to form a skin between the shaft and the soil.

Bentonite is a non-newtonian fluid, meaning that it is a solid until aggitated (by driving the shaft) where it will turn to liquid. Once aggrivation stops, it will return to a solid again. the bottom ring would need to be driven deeper than the base of the well, and used as a stop end former for a mass poured concrete base for the well.

before you go too mad sinking boreholes etc, get a professional team of hydro-engineers in to assess your ground with a percolation test. the reason i suggest this is that i worked on a scheme once where the farmer wanted to sink a borehole. The water table was literally only a few metres below the surface. he duly spent a shed load of money installing all the kit, only to find that he could not draw any water. the reason being that the soil was practically pure clay at the depth he wanted, meaning it effectivly acted as a natural impervious barrier to water movement.

Had he had a percolation test done at the depth, he would know how much water you could expect to seep through the soil - so many litres per hour, and then he could have weighed up whether it was worth all the effort.

Good luck and let us know how you get on. it is a fascinating thing to do and i for one would like to see it progress!

[TheDreamer]

Hello Folks,

I've been doing some research into the digging of wells and I've been in touch with the environment agency who have provided the following information about licensing etc. It does appear from the email that you in fact do not need one if you are only taking out small quantities of water...

Mark


Thank you for your enquiry regarding abstraction licensing.

If you abstract 20 cubic metres or less of water per day you do not need an abstraction licence.

20m3 is equivalent to:
• Just under 4400 imperial gallons.
• 2000 buckets full of water
• 20,000 litres
Therefore, if you are only abstracting roughly 50 gallons a week, you will not require a licence. The Catchment Abstraction Management Strategies (CAMS) do not effect abstractions below the 20 cubic metre limit.

However you may wish to notify the British Geological Survey that you are creating this borehole for their records. Although this is not a legal requirement for a domestic borehole they would interested in adding this information to their records. You can view their website from the link below.

http://www.bgs.ac.uk/

I trust this information is of use.
Should you have any further queries please contact us and we will be happy to help.
Kind Regards
James Pearson
Customer Service Advisor
National Customer Contact Centre
08708 506 506
enquiries@environment-agency.gov.uk

[Floyd]

My solution to geting water to the croft was rather different. Have no supply, we located a spring up the hill around 500meters from the croft. Dug down 8 feet until it bubbled throught the sand substrate. From here we buit a small square dam which was then piped to a sediment tank and then into an 1100 litre tank which was previously used for shiping Orange concentrate from the states (you will learn that where I live we make use of pretty much everything!)

At the moment I have the horrible prospect of locating a leak in the 500 meter buried MDPE pipe. I plan to plant watercress around the outflow of the main tank, and fence against the peszky deer, rabbits, goats. Maybe claymores would be better suited!