Pond Boss Forums Thread Like Summary - Pipe flow calculator

Good morning, gents. After 'thinking' of rebuilding a 5 acre pond on the property that stood for 23 years, I'm finally at phase one, which is clearing the property of trees and identifying the rerouting of the creek that feeds it. On a flow calculation of that 6in deep x 6ft across creek, we get an estimated year round flow of 750 gallons/min. My local (and experienced) pipe and culvert supplier was initially recommending a tandem 10in siphon system, but I would like to educate myself on what the actual pipe sizes should hold.

The previous lake used only a gate for draining, used a large earthen emergency spillway year round, and had no riser pipe.

Thanks for any input you have- this has been a dream since 1972 of my Grandfather, Father, and now me. In 2025, we're going to get it done!

It's not as simple as that. You have to calculate the amount of watershed that is feeding the pond, and determine how much rainfall will run to the pond in 100 and 500 year rain events. That amount depends on the type of vegetation or lack of vegetation in that watershed. The easiest way to do that is go to your counties NRCS office and talk to them.