Irrigation system fed from a river

[Mike Leary]

Originally Posted by mitchgo

At the same time mike dogs like regular rotors too

My dog will run to every single rotor that is on and bite it

When you go into business for yourself, fire the zones and let the pup go, as long as the client is not home.

[ple_1969]

Wet Boots - thanks on the suggestion on the jet pump. Did some research yesterday and found this pump. Looks like I will still be able to maintain good pressure at 20 GPM. Your thoughts on this?

[Wet_Boots]

Again, what are you doing with this "good pressure" that cannot be done with less? There is no law that requires 50+ psi at the base of a rotor head. Also, going up in flow increases your pipe costs, and a multi-stage pump like the HSJ series can blow a poly mainline if a zone valve closes unexpectedly.

[ple_1969]

I would like to have 35-40 PSI at the heads if possible. If I can get a PSI at the pump at 60 PSI I will be able to achieve this. I have calculated the following:

150' schd 40 2" mainline- 1 PSI loss
Filter 2" - 3 PSI loss
Valve 1.5"- 3 PSI loss
Elevation change (20' aftger pump) - 9 PSI
Laterals poly 1.5" - 4 PSI
Fittings - 5 PSI
Heads - 35 PSI

This totals 60 PSI

If I cannot get 60 at the pump, sure I could run a lower pressure.

[Wet_Boots]

9 psi loss in your laterals and fittings does not compute. Almost all the pipe friction losses can be cut to minimal, except for valves and funny pipe and their elbows, which take away a psi or two, because of turbulence.

I don't see you getting your money back by spending the extra hundreds on a multistage pump. That said, extra pressure is always nice as screwup insurance.

If you were on level ground next to a lake, you could do good work with the 1 HP jet pump.

Aside from Goulds, you can get a 1-1/2 HP jet pump from Flint & Walling, and theirs seems to offer more performance. 18 gpm would get you where you need to be, and the lower flows let you use 1-inch zone valves.

[ple_1969]

Thanks Wet Boots, let me look into the F&W pump.

[Wet_Boots]

the F&W pump might be pricey, though ~ if you were doing an all-rotor system with Maxipaws and scrubber valves, you might get away without a filter/strainer, provided you had a trustworthy inlet screen in the river.

[ple_1969]

I'm going with Maxi-paws and looking into the Rainbird PESB (or similar). If I can get away with not using the filter that's a few bucks I can save (as well as PSI loss). Would that be risky?

[Wet_Boots]

It depends on the inlet screen. If the river is shallow, you might have to try to float a screen. I don't know of any ruggedly-constructed ones like I would want in flowing water.