Underground Water Tank.

frankie52 · January 30, 2011

I'm contemplating having built an underground water tank, in concrete, of around 150,000 litres.

Anyone any thoughts, ideas, suggestions, recommendations etc. regaring such a project.

Thanks in advance for your info.

Artisi · January 30, 2011

Establish where the standing watertable is, during the wet session, if only a few feet below ground level then any underground tanks become a boat , ie it could float and pop-out of the ground if you pumped it to a low level.

doglover · January 30, 2011

Provide access to the cistern for inspection and cleaning

sometime · January 30, 2011

Are you sure you got your figures right 150.000 litres. that's the size for a condo water tank, nearly 3 times the size of my swimming pool.

Edited January 30, 2011 by sometime

billd766 · January 30, 2011

I have gone into this a little and for me it is a non starter.

The problem is that I live on a slope and about 1 metre down I come into rock which makes it possible but it would be long and wide.

150,000 would give you a tank of 1,500 cubic metres or at 5 metres deep it would be 10 metres wide by 30 metres long. The one I was planning was 6 x 4 x 3 metres deep or a little lass than half the size of the one you would like to build.

The reason I chose 4 metres wide was that you can buy precast slabs 4,000 x 300 mm to make a roof for the tank. All the weight will be taken by the base and walls but bear in mind you will be putting 1,500 tons of water into that hole and depending on the depth of the tank will be the thickness of the concrete walls and base.

Also remember that for 1,500 cubic metres of water tank you will have to take out more spoil that that for the concrete.

Sometimes up here there is no water for a month or so during march, April and early May and despite the heavy rain last year my fishpond is now empty and drying out. Given that it holds about 400,000 litres and it leaks through cracks in the rocks as does the neighbours on each side it was a waste of money.

If you need more information pm me and I will dig the file out.

katabeachbum · January 30, 2011

Are you sure you got your figures right 150.000 litres. that's the size for a condo water tank, nearly 3 times the size of my swimming pool.

more than 100.000 litre/100m3 you need a buildingpermit

billd766 · January 30, 2011

I have gone into this a little and for me it is a non starter.

The problem is that I live on a slope and about 1 metre down I come into rock which makes it possible but it would be long and wide.

150,000 would give you a tank of 1,500 cubic metres or at 5 metres deep it would be 10 metres wide by 30 metres long. The one I was planning was 6 x 4 x 3 metres deep or a little lass than half the size of the one you would like to build.

The reason I chose 4 metres wide was that you can buy precast slabs 4,000 x 300 mm to make a roof for the tank. All the weight will be taken by the base and walls but bear in mind you will be putting 1,500 tons of water into that hole and depending on the depth of the tank will be the thickness of the concrete walls and base.

Also remember that for 1,500 cubic metres of water tank you will have to take out more spoil that that for the concrete.

Sometimes up here there is no water for a month or so during march, April and early May and despite the heavy rain last year my fishpond is now empty and drying out. Given that it holds about 400,000 litres and it leaks through cracks in the rocks as does the neighbours on each side it was a waste of money.

Sometime said

Posted 2 minutes ago

Are you sure you got your figures right 150.000 litres. that's the size for a condo water tank, nearly 3 times the size of my swimming pool.

It depends if you are a farmer or not.

If you need more information pm me and I will dig the file out.

frankie52 · January 31, 2011

I have gone into this a little and for me it is a non starter.

The problem is that I live on a slope and about 1 metre down I come into rock which makes it possible but it would be long and wide.

150,000 would give you a tank of 1,500 cubic metres or at 5 metres deep it would be 10 metres wide by 30 metres long. The one I was planning was 6 x 4 x 3 metres deep or a little lass than half the size of the one you would like to build.

The reason I chose 4 metres wide was that you can buy precast slabs 4,000 x 300 mm to make a roof for the tank. All the weight will be taken by the base and walls but bear in mind you will be putting 1,500 tons of water into that hole and depending on the depth of the tank will be the thickness of the concrete walls and base.

Also remember that for 1,500 cubic metres of water tank you will have to take out more spoil that that for the concrete.

Sometimes up here there is no water for a month or so during march, April and early May and despite the heavy rain last year my fishpond is now empty and drying out. Given that it holds about 400,000 litres and it leaks through cracks in the rocks as does the neighbours on each side it was a waste of money.

Sometime said

Posted 2 minutes ago

Are you sure you got your figures right 150.000 litres. that's the size for a condo water tank, nearly 3 times the size of my swimming pool.

It depends if you are a farmer or not.

If you need more information pm me and I will dig the file out.

The volume was estimated from the typical water consumption per person per day of 250 to 300 litres. Given that during the rainy season I don't need to make provision for saving water I think 150,000 litres is reasonable to see two persons through the rest of the year.

Also I think you will find, if you check, (http://www.poolandspachemicals.co.uk/volcalc.htm) that 1,000 litre = 1 cubic metre therefore the tank size needs to be 150 cubic metres not 1,500 cubic metres. Usig your suggestion of 4 metre long precast slabs then the size I would go for would be 12 x 3 x 4 which gives a volume of 144 cubic metres or 144,000 litres.

CDNinKS · February 2, 2011

I am doing this as well, although not as large. Mine will be 4 x 4 x 3 meters deep or 48,000 liters. I don't plan on being able to last a year on that amount, just to tide me over any drought/water shortage problems and save some rain water. I have been quoted as low as 80,000 baht to a high of 160,000 baht to build this tank.

I should add that a cheaper method than forming and pouring concrete may be to use the large concrete rings and stack those up. I have a friend on Koh Samui that says this works.

Edited February 2, 2011 by CDNinKS

frankie52 · February 2, 2011

I am doing this as well, although not as large. Mine will be 4 x 4 x 3 meters deep or 48,000 liters. I don't plan on being able to last a year on that amount, just to tide me over any drought/water shortage problems and save some rain water. I have been quoted as low as 80,000 baht to a high of 160,000 baht to build this tank.

I should add that a cheaper method than forming and pouring concrete may be to use the large concrete rings and stack those up. I have a friend on Koh Samui that says this works.

That's an interesting suggestion. Thank you.

billd766 · February 5, 2011

I have gone into this a little and for me it is a non starter.

The problem is that I live on a slope and about 1 metre down I come into rock which makes it possible but it would be long and wide.

150,000 would give you a tank of 1,500 cubic metres or at 5 metres deep it would be 10 metres wide by 30 metres long. The one I was planning was 6 x 4 x 3 metres deep or a little lass than half the size of the one you would like to build.

The reason I chose 4 metres wide was that you can buy precast slabs 4,000 x 300 mm to make a roof for the tank. All the weight will be taken by the base and walls but bear in mind you will be putting 1,500 tons of water into that hole and depending on the depth of the tank will be the thickness of the concrete walls and base.

Also remember that for 1,500 cubic metres of water tank you will have to take out more spoil that that for the concrete.

Sometimes up here there is no water for a month or so during march, April and early May and despite the heavy rain last year my fishpond is now empty and drying out. Given that it holds about 400,000 litres and it leaks through cracks in the rocks as does the neighbours on each side it was a waste of money.

Sometime said

Posted 2 minutes ago

Are you sure you got your figures right 150.000 litres. that's the size for a condo water tank, nearly 3 times the size of my swimming pool.

It depends if you are a farmer or not.

If you need more information pm me and I will dig the file out.

The volume was estimated from the typical water consumption per person per day of 250 to 300 litres. Given that during the rainy season I don't need to make provision for saving water I think 150,000 litres is reasonable to see two persons through the rest of the year.

Also I think you will find, if you check, (http://www.poolandspachemicals.co.uk/volcalc.htm) that 1,000 litre = 1 cubic metre therefore the tank size needs to be 150 cubic metres not 1,500 cubic metres. Usig your suggestion of 4 metre long precast slabs then the size I would go for would be 12 x 3 x 4 which gives a volume of 144 cubic metres or 144,000 litres.