Lavarock64,
On the test holes I would recomend one in each corner, in about 45 feet from water line. This would be roughly where the toe of the slope meets the bottom.
Getting the layout on paper is good. Figure out how much cut (excavation) and fill (dirt in the dam) you have. Unless you want extra dirt getting the cut and fill to balance (cut = fill) is ideal. From the test holes determine how deep and long of a core trench is needed.
# 3; Contracts are typically for cubic yardage of earth excavated and compacted into the dam, on dams that balance. If dirt has to be brought in or removed it would have it's own price.
Cheapest is not always best. The topsoil should be saved and put back on top which means it has to be moved twice, once to get it out of the way and then back. The core should be dug out and compacted back in. Watch for the cheap bid that will charge extra for these.
Rather than leave the contract loose, also negotiate a reasonable hourly rate for anything extra you might want done after the pond is built, which falls back to putting what you want on paper so if you want the banks to jut out into the water they will be dug that way. Saves you money and the contractor headaches.
Hey Dave, always happy to be called a pond builder and dozer guy.

Make it look easy,
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