I know this is an old thread but yes it works! I started with a large pond which was dug out and a liner put in. It held about 10,000l of water.
It was lined and filled up at the start of last summer. At first, the pond would need a top up every couple of weeks of an title water due to evaporation. Then some water was leaking from an irrigation pipe orn ome thing nearby and collecting in the pond under the liner. This caused the liner to bubble up and made a right mess of things as the ducks were then standing on the liner and putting holes in it.
Right after this happened, the pond would drain down really low in a day or so, due to the holes, which Id spend hrs repairing. But the problem with water coming under the liner had not been diagnosed or fixed, so the liner kept coming back up and getting more holes.
This of course as well as pond drainage resulted in pond wate full of duck poop leaking under the liner and sitting there on then sol, creating what I have recently found out is the right environment to 'gley' a pond, letting stuff degrade in an anerobic environment.
Anyway over winter the liner got more rips and tears and as well as water undr it there was air and liner bubbling up all over the show, a complete mess. However, the water levels stayed constant.
I thought it was maybe just because it was winter and damp ground etc.
However i eventually decided, after trying to drain it and remove the muck, that Id just get rid of the liner (which had so many holes and rips it was like Swiss cheese, with hardly any cheese!) and then it would drain easier and Id be able to clean it out and replace the liner and refil.
However it is now mid to late summer, one of the hottest in recorded history. The ground has been parched dry, temperatures well into the 30s(C) most days and I have already cut up and removed huge chunks of the liner, leaving around 1/3 or more of the pond totally unlined. Last summer this would have basically emptied the pond within hours, a day tops. This summer, the water levels are remaining as constant as they would if the pond had a complete, hole, rip and tear free liner. The pond muck has very effectively waterproofed the pond.
There is a lot of it on the bottom which needs removal, and I am planning to test it in two ways:
1: dig a small indent in the ground and cover it with this muck, let muck dry and test for waterproofness. If I am feeling energetic enough, I'll dig a similar sized indent right beside it and not treat it and fill both with water to see what happens
2: line hole with duck muck, then cover with some of the Old pond liner to facilitate an anerobic(no oxygen) environment for a couple of weeks. It's the anerobic breakdown of muck and poos that creates the waterproof layer I read. Test one, is because I know the pond muck has already been created in an anerobic situation (due to the nasty sulphur smell) so im testing my theory that it doesn't need to be covered and left for the anerobic bacterial process to occur, it already has.. So test 2 won't happen if test one results in a waterproof pond.
Anyway the moral of my long winded post is that yes, from personal experience I am sure that duck poo will waterproof a soil pond. But it has to be allowed to build up to a reasonably yucky state, to ensure its being broken down anerobically, not aerobically. So you probably need to intentionally get kinda slack on the cleaning lol.
I should also note that where I live the water table is a long way below them level of my pond, as in about 20-40+ metres and the pond is less than one metre at the lowest point. It's water holding ability is dramatically different from a year ago, where it simply woupd not have been possible to retain any water in it over summer without the bottom covered with a complete, and100% hole free liner. I plan to remove th rest of the liner as time allows ndc up sides and bottom with sand to minimise the muddies of it. I read that a gleyed will stay waterproof for a couple of years. however that was referring to ponds without ducks. I am hoping mine will keep the pond permanently waterproof.
i also reckin the muck on the pond bottom, could be used to make one of those primative mud dwellings, and it's great on the vegie garden, but only mixed with plenty of soil or sand, else it of course, won't drain
