You might not have lost yet.

I would think that best case scenario is that the leak is in a less that 5' square area. Maybe it's just wishful thinking.

I would also think that your best time to be at the pond would be within an hour or so of it leveling off. Get out on the boat and visually inspect the new shoreline.

Excerpt from Robert Crais' "The Monkey's Raincoat:"
"She took another microscopic bite of her sandwich, then pushed it away. Maybe she absorbed nutrients from her surroundings."