Thanks Theo. I need to finish the book and it probably tells me this, but it gets you thinking of these questions. Now that I've done the calculations I have a rough idea of how many gallons of runoff water I'll have, and I have an idea of how many gallons my pond will hold, then what? Does a feasible pond require one year's runoff to roughly equal the pond's water retention volume? That's about how my calculations worked out for my pond site. Once it's full that seems like a lot of water coming in if you figure the pond gets an equal amount of water to it's total volume each and every year.
Here's my stats for anyone who wants to confirm the calculations: pond will be .75-1 acre, 18'=20' at dam so 9'-10' average depth, 6 acres drainage area using contour edges from topo map (10 acres if use midpoint of top countour area - see question 1), 36" annual precipitation.
