Thanks for the advice guys. We have lots of sunny days here during the winter, it doesn't snow all the time but when it does, it usually sticks around for awhile. I will make a point of removing any snow once I get fish back in the pond next year.
This year I did lose some trout at the peak of the summer heat, but I started aerating with my handy trash pump for 4-5 hours per day and they survived the rest of the summer even when the pond leaked down to only 5-6 ft of water. This is the first year I've had trout so I have not had any winter over experience yet. Last winter a few bass and bluegills made it through the winter, but only a few. It had about 6 ft of water in it last winter.
I've assumed that the muck on the bottom is silt from several of the big rains we had over the last 3 years, one big enough to almost take out the dam, and that filled in the upstream sedimentation galleries with 4-5 ft of rocks and sand. HEnce the need for digging it out again, and rebuilding the galleries before we get another one of these flash floods (happens about once every 10 years the locals tell me, except it's happened twice in 3 years!)
It is a narrow site, and I plan to try to compact the clay on the steepest sides with the track hoe bucket or the skid loader. I may have to slope them a little more to get that 2:1 slope. I will plan to try to get as deep as I can over 1/3 of the pond bottom, then build in some shelves and shallow gravel areas for the bass and bluegill spawning redds.
Hopefully all this starts tomorrow! Thanks again, it's so great to be able to get this kind and quality of info from your website! Barbara