My Well Needs Double-Lining Because Of Sand Infiltration

[simon43]

I subcontracted an experienced company (Thai family business) to dig 2 water wells for me on 2 separate plots of land near to the airport.

The first plot was on an area of higher ground, and the well-diggers dug it to about 12 metres in depth, using 1.5 metre diameter concrete rings for the lining. That well all seems toi be working OK, (using a 2-pipe pump to draw water up from this depth).

The second well was dug on the second plot, with the water table being only about 3 metres below ground level. The company dug down to 8 metres, and again lined the well with 1.5 metre diameter concrete rings.

However, after they finished that task, they explained to me that due to the sandy nature of the soil, fine sand was infiltrating the well water through the small gaps between each ring. To counteract this, they said they will install an inner well, using 1.2 metre diameter rings, but of course at extra cost to me.

Now this sounds rather strange to me. My old hotel had a well installed in sandy soil, and we used a sand filter to remove the sand prior to piping the water to our shower units.

For these new projects, one possible salient fact is that the first well is for a project owned by a Thai (my ex-wife), and the second project is owned by a farang...

I have never heard about double-lining wells. Right now, the well that has been dug on my land looks fine and is full of water. I'd much prefer to use a sand filter if that will solve the apparant problem that I'll have with the sand, rather than pay about 25,000 baht extra to these lazy well-diggers for a double-lined well, (and I'm not convinced that a problem exists or that double-lining is the way to fix it!).

Any comments from experienced well-diggers??

Thanks

Simon