I need to do more digging but my primary agenda at this point is getting the water out. My original plan was to observe the loss until it stops so I'd have an idea what level the leak began. Fortunately and unfortunately it isn't leaking fast enough before spring rain will hit and fill back up. Last year it was much lower by this time so I know that sand must extend out a ways. You can see in one of the pics a large dirt pile across the pond. One 4 times that size is back behind where I was standing. It was used to basically extend the dam on around I think. There is basically zero organic matter in the pond anymore. Maybe half on inch of dead leaves was over the sand.