This guy sounds like he doesnt know too much about dirt. You can never get compaction when dumping dirt into water, or a hole filled with water. The water will saturate the dirt and it will basically turn to jello, goo or sludge. There's a dozen differnt terms, but it all boils down to soil that loses all integrity.
If you have a hole with water in it, like your core trench, you need to get the water out before putting dirt in. This applises to stumps, building footings or just post holes for a fence.
He dumped enough dirt into the core to cover the water and drive over it, but there is no way he could get that soil to compact. It wouldn't matter if he had a sheeps foot or not, it's impossible to compact sludge.
The water coming out down streem from your dam could be from allot of differnet reasons. In fact, there are too many options to even guess. The dam was never sealed, so it's probably just leaking out the bottom.
The only other thing to consider is if this water is a seperate spring. With all the rains I've received this year, I have springs all over the place. Some are feeding water into my pond, others are turning areas of my land into a swamp.
Eddie
