Backyard Aquaponics
A place to discuss aquaponics

Sorry Simon, no. This was just what I was told by the hatchery. He was most adamant about the fish not being able to escape to any waterways.
Check the DPI&F here they should be able to help you out.

Hi Simon, like Jaymie says do your research...

the DPI legislation used to (haven't checked for a while) prevent you from having any fish farm/pond/tank/aquaculture pond etc within 100mtr of the 1 in 100 flood level....

Things have loosened up a little over the last few years but they can still be very strict depending on State/area location and species of fish...

try pirahnas

Very common problem Simmon. I have 4 dams/ponds at my place and pretty much all of them leak to some degree. I tried bentonite on one of them and found that it didnt improve it at all. One of my dams has the same problem as yours in that it will maintain water at a certain level but when full drops back to that level after a few days.
You can use sheep or cattle instead of pigs and feed them out hay in the dry pond bed but this method is usually used in new dams to aid in compaction of the soil.
I wouldnt go the liner option myself as they are pretty expensive and once you get a hole in it you are back to square one again.
I think your best bet would be to get the excavator back in and and get him to remove some of the soil from the dam wall and replace it with clay from the bottom of your pond and then put the top soil back over the top of the clay. I think you will find that the leak will be near the bottom of the dam (often its where water used to flow underground before the dam was there) and its just the added presure on it (when its full) that causes the water level to drop.
I know that Marron will actually try and seal a leaky dam so putting Redclaw (do they burrow?) in may do the same thing. Avoid Yabbies though as they burrow and could actually make it worse.

Hi Troutman,

What do you think the likelyhood would be of worsening the problem by digging down into the dam? Could I possibly cause the water to leak out through the bottom by excavating downwards?

S

I had it done to two of my ponds and both are now much better than they were and they seem to keep improving with age. I know that with my soil once you get past the top soil there seems to be a never ending supply of clay no matter how deep you dig. I dont know what the soils are like where you are but generally the deeper soils hold water better than the surface soils so you should be ok.

Thanks for the input.

I think I will give Troutman's suggestion a try.

S

but don't they grow / breed silver perch in earth dams in QLD? Ath the hatcheries?

and then i complain when i fall asleep in the driveway after turning off the ignition

Just had a look at your pic of the dam again. I notice that you have a few reasonably large trees near the dam. The problem with trees near dams is that their roots often work their way through the ground to the water and in doing so makes an underground channel where water can flow. This problem becomes even worse if the tree dies and as the roots rot away they can leave quite a large tunnel for the water to flow out of.

Is the dam wall over on that side near the house?? If there is no evidence of wet patches around there I recon the water would be escaping near the bottom of the dam and not thru the wall.

If you go the bentonite option there are 3 ways of doing it. The most common way (and the least likely to be successful) is where you sprinkle bentonite across the surface of the dam (when its full) and hope that it gets taken into the hole where it will expand and block it off. The other methods will still involve an excavator and you basically move the soil off the internal side of the wall and then layer the bentonite over it and then replace with the soil. You should only need to use this method if you dont have enough clay on site.

Good luck

Whats that concrete along the closest edge?? Does it go down into the dam?