tim k,
Thanks for that good Texas "data point" for the discussion.
35 GPM is 50,000 gallons/day.
In a 2-acre pond, that is 0.93" of water losses that it is balancing every day.
That "seems" a little high, since a lot of the literature estimates summer evaporative losses of 1/4-1/2" of water per day. However, in the real world, the pond almost certainly also has a leak rate greater than zero, and the emergent plants and the shore plants near the edge of the pond have a significant transpiration rate of water loss to the atmosphere when they are growing in full summer daylight.
