Is it possible to calculate the max flow rate (gals/m) achievable through a given piping system with only the following variables? - 4" SDR 11 HDPE pipe (3.633" ID) - 28,000 feet of pipe from source to destination - 90' of elevation change from source to destination - destination is another pond, pipe is open ended and 90' higher than source. - 150 roughness value I'm trying to figure out what size of centrifugal pump to place at the source pond and what flow rate is possible. I'm not very smart about this type of thing. I Googled it, but every calculator I found wanted either velocity or flow rate, which I don't know because there is no pump there yet..? Thank you.