Pond - Drainage of water below liner

[Ambrose]

I am currently working on a landscape project for a client of mine, the problem is, as weve recently dug out the pond area it is all clay and is already holding water due to the rain weve just had. The question is, once ive installed the liner and filled the pond up and the waterfall and everythings up and running will further rainfall cause problems once it manages to get under the liner? I am also constructing a waterfall which is going to go on the banking about 3 foot higher than the pond level, again all the rainfall that gathers at the top of the banking will also run down into the area where the pond is. Can anyone tell me if drainage is going to be required below the pond liner and if so what type and how do i do it?
the pond is 8ft x 8ft x 2.5 ft
Thanks

[Tony McC]

What would happen if the pond/pool overflowed? Is there an escape route for the water?

If your pool is situated in a 'low spot' and any overflow or surcharge would cause problems, then a sub-liner drain might be necessary, but to where could it drain? Is there any chance of getting it linked into the SW system or is there a soakaway on site?

[Ambrose]

Thanks Tony
There is a liner drain about 2-3 metres away which could handle the amount of water if the pond overflowed. Its just that with the pond being dug around 2.5 ft deep into clay, its basically a clay bowl - which is holding water, what im thinking is that when i eventually install the liner and stock the pond, all the water from around this area (after rainfall) is still going to follow the easiest route, which i think will continue building up in the (clay bowl) below the pond liner. Eventually wont his cause problems for the pond with alll the water developing below the liner? I cannot think of any way to get the water out of here, the nearest man hole is around 20 foot or so away and right on the other side of a new patio the client had installed previously!

[Tony McC]

Any chance of running an overflow pipe from the pond to the linear channel?

[Ambrose]

Thanks for the reply Tony,
Yep i dont see a problem with running an overflow pipe from the pond to the linear channel. But what about the water that gathers between the liner and the clay - do you think this will cause problems? Basically with it being at the bottom of the banking i suspect all the rain water will gather underneath the liner and have no-where else to go with it being clay, ill get on with installing the overflow for the time being, but any suggestions on how to get rid of the water thatll gather below the liner as well?

[flowjoe]

I’m not big on ponds but presumably intercepting any storm water run off is preferred to having water drained from beneath the pond, is it not possible to trench around the excavated pit installing a ring of land drainage into virgin clay, if you overlap the pond liner and fill with a granular fill will this not act as an overflow as well to some degree ?.



Edited By flowjoe on 1117998220