A bit of old business to get out of the way.
Bongo found a calculator.
He displayed it for us at Knoll Lake campground up on the Mogollon Rim.
This is just after the General Crook trail hike, at the campground, with the "adults".
Later we found the calculator's owner. Turns out he works with us...
And...
Looking north over the dam down the itty-bitty stream below.
The campground is a good quarter mile from the lake - you can't reasonably carry watercraft that distance. Keep it strapped to the truck til you're ready hit the water.
The lake has an island, but the shores are precariously steep all the way around (as is common in a flooded canyon). You'd have to be really determined to camp on it.