Advice on an underground water leak

[Atanasio]

I need some advice on how to detect an underground water leak / illegal branch.

As background I am the President of a Spanish water community serving about 30 rural properties distributed over several square kilometres. We pump water from a lower deposit to a higher deposit that then feeds the properties, with the height / gravity of the higher deposit providing the water pressure. The upward pipe is PVC 90mm and is buried underground, often under concrete and running through private land. The pipe is about 2 km long. The pumping operation is not continuous and only runs when the higher deposit reaches a minimum level. There are not meant to be any branches off this main upward pipe with all supplies to individual properties run off of a separate downward pipe network.

Every time water is pumped up 20% does not arrive at the higher deposit. During the summer this will run to hundreds of cubic metres of water over a three month period. I have used a local company to try and locate the problem and they have been unable to do so. They have tried pressure testing and seem to have dug a number of holes.

We suspect one particular local farmer has illegally branched in but where the upward pipe crosses his land he has concreted over and will not give access. Using the police to gain access is not an option. As an added complication most properties have their own water deposits for security of supply and so any theft is difficult to spot as it flows into private deposits.

The leak / illegal branch could of course be elsewhere and there may be more than one. The local company seems to have run out of ideas and more importantly a desire to solve the problem.

I have looked into simply laying a new pipe but it will cost several thousand Euros due to the length and terrain.

Can anyone offer any suggestions?

 

[dcawkwell]

Cap off the pipe that is filling the higher reservoir.

Cap off the pipe before it enters the land of the farmer you think has
tapped into the pipe and cap off. Pressure test between the low point
and the farmers land.

Cap off between farmers land and high point and pressure test the line.
If both lines are good. Re-route the pipe around the farmers land as
this is where the leak or branch is.


Hope this suggestion helps.

 

[Atanasio]

Cap off the pipe that is filling the higher reservoir.

Cap off the pipe before it enters the land of the farmer you think has
tapped into the pipe and cap off. Pressure test between the low point
and the farmers land.

Cap off between farmers land and high point and pressure test the line.
If both lines are good. Re-route the pipe around the farmers land as
this is where the leak or branch is.


Hope this suggestion helps.

That sounds like a sound approach. I'll let you know how it goes.

Thanks

 

[Onetap]

If he has made an unauthorised connection, he may have an isolating valve that he will close as soon as he sees any pressure testing work underway. Then there will be no apparent leak. If so, you could pressure test all the pipe on either side of his property,as suggested above; it would confirm that the 'leak' is on his property and that he controls it.

You may be able to find a drain inspection contractor with a submersible inspection camera which could locate a tee connection in the pipe from an access point outside his property. I know these can extend 100m, but I don't know how far they can reach. If the suspected tee is a long way from his boundary, you may not be able to reach it with a bore scope.

You might be able to put a smaller pipe through the section on his land and connect it to the existing pipe on either side. The await digging work through the concreted over section.

If you found a tee, presumably you'd then be able to bill him for all the water he has taken and the work involved in identifying his connection.

 

[Norcon]

Could something like this not be used?
http://www.accepta.com/details.asp?cat=500&scat=20&id=3554

Cap off the upper resovoir supply and start pumping.
Then go unto his farm covertly and see if it can be detected.

Or connect the pump suction to a sewerage line.

 

[Atanasio]

If he has made an unauthorised connection, he may have an isolating valve that he will close as soon as he sees any pressure testing work underway. Then there will be no apparent leak. If so, you could pressure test all the pipe on either side of his property,as suggested above; it would confirm that the 'leak' is on his property and that he controls it.

You may be able to find a drain inspection contractor with a submersible inspection camera which could locate a tee connection in the pipe from an access point outside his property. I know these can extend 100m, but I don't know how far they can reach. If the suspected tee is a long way from his boundary, you may not be able to reach it with a bore scope.

You might be able to put a smaller pipe through the section on his land and connect it to the existing pipe on either side. The await digging work through the concreted over section.

If you found a tee, presumably you'd then be able to bill him for all the water he has taken and the work involved in identifying his connection.

You make a good point on the isolating valve as the local contractor has pressure tested the pipe and was not able to locate any problems. Where they were working was visible to this farmer. Further he built the original network when it served just a few properties and he has full knowledge of where the pipes are laid and has a good knowledge of the subject.

Unfortunately no chance of getting anything back from him. Life in Spain is never that simple and if you get me started I'll fill this form and bore you to death!

Thanks for your help and other suggestions. All will be tried next week.

 

[Agile]

This problem highlights the difficulties when a pipe crosses land not in your ownership.

In the UK anyone doing that would have a proper legal wayleave agreement setting out all the rights and conditions and anyone flouting them would be liable to court action. There would also be annual payments for the wayleave.

Tony

 

[Atanasio]

Could something like this not be used?
http://www.accepta.com/details.asp?cat=500&scat=20&id=3554

Cap off the upper resovoir supply and start pumping.
Then go unto his farm covertly and see if it can be detected.

Or connect the pump suction to a sewerage line.

Thanks for your idea on the capping and this will go on the list. I looked at the link and I would be concerned with the safety as it is going into his drinking water supply.

I like your style on the sewerage!

 

[Norcon]

What kind of operation is the farm running?
And what volume is in the 20% at each pumping operation?

 

[Agile]

Further he built the original network when it served just a few properties and he has full knowledge of where the pipes are laid and has a good knowledge of the subject.

In that case it would be reasonable to expect him to have added some outlets to supply his farm water needs.

Since a cow drinks about 110-220 litres per day with a large herd that could be quite a lot of water!

You could count his cows and multiply by say 160 and see if that equates to the missing water.

Tony

 

[Atanasio]

What kind of operation is the farm running?
And what volume is in the 20% at each pumping operation?

At the moment we pump about 150 cubic metres per week, so 30 cubic metres gets lost. During the summer this will increase to 500 cubic metres per week being pumped and 100 cubic metres being lost per week. Many of the community members have smallholdings and all will require irrigation for gardens plus water for pools etc.

The farmer has several acres of land which is turned over to a variety of trees, plants etc, all of which is very green. He has a large underground deposit and so would not have an issue with absorbing and using the missing volume of water. He claims that he has his own well and augments his water needs with this but it has rained only a handful of times in the last eight months and most wells around are pretty much dried up. Hence our suspicion. I should also add that he is a rather unpleasant and aggressive character who refuses to let anyone on his land.

 

[TicklyT]

http://www.primayer.co.uk/wlc_combined_enigma.htm supply useful equipment for water leak detection / unauthorised use.

If you know the distance between accessible fittings, and the pipe material, a set of 8 'Enigma' correlators will cover 2km of cast iron / ductile iron, or about 400 Metres plastic main at a time of, and locate the 'leak' to within a few metres.

The closer the spacing of the correlators, the better the resolution of the result.

We regularly use them to detect potential leaks if overnight water consumption increases unaccountably in an area.

 

[Norcon]

Atanasio wrote

I looked at the link and I would be concerned with the safety as it is going into his drinking water supply.

I think some of them are safe.
http://www.prestodye.com/water-trace.html
They say.. "The dyes are safe, non-toxic, and biodegadable. Sunlight also breaks down the color."
Does the land have a net work of irrigation piping? Should be easy enough to take a sample.
At the end of the day you could just add a safe concentration of salt or some other safe substance to the water and do before and after tests on his supply.
Getting the farmer out of the equation should be your first priority before embarking on expensive leak detection operations imho.
If the tests turn out positive then maybe diverting the pipe line around his property is an option?
You can ask him if he wants a meter fitted.

Directional drilling might be an option and leaves the ground works looking less like a scene from the somme.
They can go 100m at a time when laying gas mains.

 

[Atanasio]

Thanks everybody, I have a lot to do next week and so will be back to say job done or to seek further counsel. Your comments are much appreciated.

 

[s123mith]

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