Leak in Dam Wall

[Kiwi Phil]

I have a dam with max holding capacity of 3.5million litres of water.<br />We have been in drought for around 5yrs, so the dam has not reached its overflow level.<br />About 3/4's way up the wall a leak in 1st yr of drought. <br /> It has started from the clay wall drying out, and remaining dry for long periods.<br />When I get a storm come through, it does fill, then empties to this 3/4 level quickly.<br />I can not see a crack, nor can I see leakage from the outside wall, as everything is wet.<br />It is built into the side of a hill, round with a "Turkeys Nest" type construction.( like an up side down cone on the inside.<br />Has any one ever had a similar problem<br />I can not afford a plastic liner.<br />I was told to spread a type of stock feed around the water line, for the leak to take it in to the space and plug it. One pallet later, and no change.<br />The top of the wall it too narrow for machinery (maybe 6-8ft wide).<br /><br />Cheers<br />Phillip

 

[JB]

Re: Leak in Dam Wall

Have that sort of trouble in this area all the time, Phil.<br /><br />The leak may not be in the dam at all, but in the former hillside. .. crack in an underlying rock layer for example. Had that in my small pond after I dug it.<br /><br />We use a clay to seal ponds (we call them tanks in Texas). It is called Bentonite when we buy it, or caliche if we have a deposit that we can mine it from. Its wet/dry volume ratio is astounding and it is about as porous as pottery.<br /><br />You may have something similar in OZ.<br /><br />Good luck.

 

[Kenneth Brown]

Re: Leak in Dam Wall

Check out www.pondboss.com They have quite a bit of knowledge of there about this subject.

 

[Kiwi Phil]

Re: Leak in Dam Wall

Thanks for that. <br />The name Bentonite rings a bell so will check out the local Rural supplies.<br />Has any one ever laid this stuff ?<br />Will also check out KB's site.<br />Thanks very much<br />Cheers<br />Phillip

 

[Bigfun]

Re: Leak in Dam Wall

Well drillers might have bentonite

 

[Drowned Rat]

Re: Leak in Dam Wall

Hi there Phil. You may be able to use a dye to better narrow down the exact location of the leak. Dry commercial grade food dye works well and is non toxic. Sprinkle it on the inside bank near where you think the leak is and you may see it exit the other side. This will aid you with the Bentonite application. Be aware though that if your pond is not full most of the time, the bentonite will shrink and crack just like the clay you have now. Another option is to use a chemical called sodium polyphosphate. It works good on ponds with clay layers that have been damaged the way you describe by breaking down the soil aggregates and rearranging the soil structure to provide a better barrier. You will get the best results if you can re-compact the soil somehow. A "Whacker Packer" may do the job and is portable. You can rent these at home improvement stores in the states, not sure about down under. Good luck.<br /><br />