Pond Boss Forums INTRO Questions & Observations One siphon or two?

I haven't the calculation for water flow. I think there is discussion about it in past threads. It seems like the area of a pipe is pie x radius (which is half the diameter) squared. The area seems to grow exponentially. For example...

Pie Diameter Radius Radius Squared Area
3.14 2 1 1 3.14
3.14 4 2 4 12.56
3.14 6 3 9 28.26
3.14 8 4 16 50.24
3.14 10 5 25 78.5
3.14 12 6 36 113.04
3.14 14 7 49 153.86
3.14 16 8 64 200.96

Even though an 8" diameter pipe sounds just twice as large as a 4", it is actual over 4 times as large. I'm getting 14" pipe and plan for much to go over emergency spillways and such, but Illinois USED TO have more rain than Texas.