Nathen,
The logs will become waterlogged and should stay right in place. If it takes longer than I expect it to, then they might float a little for a short period of time, but the stumps on the ends should keep them from drifting. The stumps don't have a chance of floating, or at least I don't think they will.
Rob,
The sand layer had clay under it. I dug down to the clay and then went another foot to be sure. I moved all that material, wich is more like a sand/clay mix to where my shoreline road is going. This stuff hardens up like cement, but of course, it won't hold water.
I then pushed clay to that area to build up a wall on the sides of the lake where the sand kept on going out into the woods. This clay is 3 to 4 feet thick with a crown that's wider than the dozer blade. The blade is 12 feet wide. I did this in layers and drove over it a bunch each time with my tracks. It took a very long time, but I'm confident that I got a good seal.
This is also where the spillway is located and my point of reference for the water level, or height of the dam.
We've been known to get storms that dump two to five inches of rain in a single day. After the first inch, it's pretty much all run off. I'm putting in two big culverts and have a drainage canal dug that will catch the water from about a 60 or so acres and direct most of it to the lake. My roads are being built to act as funnels to direct water to the lake also. Then there is the water table that's seeping water into the area from the shoreline.
When I first started this project, there was so much water in this area I was unsure how I was going to clear the trees. Then we had a terrible drought last year and it dried up enough to get in there. It was still pretty wet in spots, but that just loosened the soil so I could get the trees out. It was too wet to dig in. This year the drought is even worse and it's dried out enough to dig. I never imagined that I'd be able to dig out this area and had come to live with the idea of it being only 2 feet deep. Now I'm around 6 feet deep and have a really nice shoreline.
My last source of water for the lake is the creek behind the dam. I own half of it, so I can't dam it up, but I can pull water from it. I'm still debating the different methods to do this, so nothing has been decided. Right now I like the idea of a pond waterfall pump running 24/7. It wont fill the lake, but it will fight evaporation.
Thanks,
Eddie