Thanks for the advice Rainman. I think you are right and I suspect my tiny springs have begun to suck.
They are still flowing and even kept an area free of ice for a while when it got cold a month ago, but now I drained the pond and took a look, I see the springs are just as tiny as they were last summer. I really doubt they have enough pressure to continue after they have more than a foot of water on top of them.
What I saw when I drained the pond was interesting.
Most of the the water running in from the back seems to be coming through the topsoil over top of the clay subsoil. I was surprised to see that except for the three small springs or seeps, no water seems to be coming in through the clay subsoil at all.
I expected water to be pouring in from a hundred places in the clay basin which is several feet below the present water table but the 2 tiny springs and seep are the only place this is happening. From what I have read here, this is probably good thing, as it seems maybe the main leaks are the aforementioned springs and not the whole clay basin.
With the amount of water coming in off the back it's impossible to get anything dry enough to really pack any of the seeps with clay. I could only manage to cover two of the seeps / springs with a foot of squishy clay, and I put some big rocks around this and on top of it. If they are going to suck between now and when it gets dry enough to get in there, they will have to suck through a lot of goop.
In the most substantial "spring" I managed to install 2 pieces of hollow metal pipe. Both with a piece of 10'long flexible plastic tubing attached. This spring is very small, but it had enough water pressure to make a new hole every time I tried to block off the old one. ( why I installed 2 tubes instead of just one. ) The pipe allowed me remove the water pressure by siphoning water from underground to a lower area and hand packing about 8 inches of clay into the basin where it emerged. Then I put a large heavy flat rock on top of that. Having two tubes has an advantage in that I can blow through one and get the other one flowing, so if they ever get plugged this might be useful. I tied the tubes to a rock near where they emerge from the spring and tied the far ends of the tubes to a string.
I didn't want to try lifting the tubes to see how high the water would climb as I didn't want to tempt the springs to find an easier route and bust through the 8 inches of goopy clay on top.
For now I will leave them to run downhill into the pond but once the pond is full I will pull the ends of the tubing above the surface and hopefully the combination if water pressure, 6 inches of goopy clay to have to suck through, and the heavy flat rock on top of the whole mess will at least slow down the leak till things get dry enough to do a better job.
Even with a tiny temporary dam to try and divert the water flowing in off the back, it was a constantly trickling mucky yucky mess....
My idea of trying to compact things better, at this time of year was one of the dumbest ideas I ever had .... Like trying to compact 3 to 6 inches of chocolate pudding onto a barn door. The sides of my pond are quite steep and every wack of the baseball bat sents the surface 3 inches of ice cold muck flying into my face and everywhere else. The dam under the 3 inches of slimly jelly clay seems to be nice and firm though.
I won't be able to really fix anything till the run off dries out at the end of next summer, but I'm glad I drained it and got to see what is going on down there at this time of year, as now I have a better idea of the most likely trouble spots.
I've seen enough mud to keep me from wondering what is going on down there for at least a few months.
Now I'm filling it back up with water.
