I've owned my property for 1.5 years now. Realized last year the 1 acre pond is losing water. I never really measured it till now. In the past, I just flagged the shore hoping to eventually find the point where it stopped dropping so I could then hunt down the leak. Unfortunately it never stopped before rain would push the level back up. So I'm preparing to apply a sealant and figure I need to measure it more precisely. I found that at 3/4 full, it lost a 1/2 inch on a cloudy day with temps in the 60s. I'm assuming none of that is evaporation.

My question is, if no evaporation takes place, should I expect to see the same drop in water level regardless of how full the pond is? That seems to be the explaination I hear frequently on this board but doesn't make sense to me. If x amount is leaking out and that amount doesn't change then I'd think the drop would accelerate as the surface area and volume shrinks... assuming the pond is bowl shaped. Then there's the hydraulic pressure issue complicating the matter. My problem is that I can't establish a control to measure my pond against. Once I treat it, I will expect no water loss on cool days but we are approaching summer with heavy evaporation exaggering the problem. I was kicking around the idea of measuring water loss in a bucket to that in my pond. Does this approach make sense or is it too oversimplified?