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Posted: Fri Feb 21, 2014 4:24 pm
by Urvishah
Hi there.
I would really appreciate some advise and possibly a solution. Last summer we removed some trees from our garden just to discover a stream of water running in our garden making the garden water logged. It is difficult to identify the source of the water as it appears to be coming from the boundary wall with our neighbours who recently had some building work done.
The water company has investigated it and they say it is surface/ groundwater. Our garden is at a lower level than the house.
We plan to put a land drain from the boundary wall leading to a sump pump to pump the water back into the surface drain.
Our architect has created a plan to create a concrete trough to collect the water near the source and then build a French drain connected to the pump.

I have a couple of concerns and questions:
1. The builders are unable to create a concrete trough as it keeps building up with water. The plan was to place a non-perforated plastic pipe in the trough but I am fearful that water may escape under the pipe and find another path to the garden. Is there any other design that we can use?
2. The design of the French drain- should we put some gravel under the pipe? Is it better to use a non-perforated pipe? What should we refill the drain with?
3. We also have a patio between the garden and the source of the water. The water is escaping to the edge of the patio as well. Is it advisable to build a land drain parallel to the patio wall?
4. As the garden is clay I suppose there is no benefit of creating a soak away.
5. Should we create more land rains elsewhere in the garden- all connected to the sump pump?

I will really be grateful for some advise. It is giving me sleepless nights.

Thank you

Posted: Sat Feb 22, 2014 5:51 pm
by Tony McC
"Builders" are probably not the people to be constructing a catchpit. It needs an experienced grounworker who knows how to deal with holes that insist on filling with water as you're working in them.

I'm also worried by an architect who uses terms such as "concrete trough" and "French Drain". Obviously not an architect familiar with drainage design, especially as he or she seems to be incapable of telling you how this "French Drain" should be contructed. Read the releavant Land Drainage Page on the main website, and maybe suggest it to your architect so they can update their very limited understanding of the principles involved.

The best advice I can give you is to ignore the clueless architect, send the "builders" back to building walls or fixing windows or whatever it is they do, and get yourself a genuine drainage specialiost who can look at the site and develop a plan which is best suited to the problems thereon, and then implement it without getting his feet wet.