Agree with esshup.
Your first period of rising water does not include the summer months.
A hot, dry day in July or August can easily evaporate 1/4" per day. If it is windy and very dry, I think you could maybe reach 1/2" under perfectly bad conditions.
A 1/4" loss for 200 days costs you 50" of water level in your pond.
I know that sucks big time. Better go read the "rain dance" thread and see what worked. (Tongue in cheek.)
