"But, John," you protest, "how much runoff are you really eliminating with your little 110 square foot pond?"
Glad you asked. Hey, math time again!
- 110 square foot pool surface area
* 1 foot average pool depth
110 cubic foot pool volume
* 7.48 gallons / cu. ft.
822.8 gallon capacity
* 66% full
That's right, in Friday's storm my little pond held well over 500 gallons of rainwater — not counting what it percolated during the storm — and ultimately released it back to the earth rather than letting it flow out to the gutters or dumping it out at my home's foundation, whether into a French drain or not.
543 gallons and counting? I'm feeling pretty good about myself right now.