pump for suction from stream

We have a half horse "regenerative" style pump runing from a stream, that lifts 4m and runs at 15liter/min for quite long periods doing garden irrigation. When you need to lift, you have to do things right.

- decent size feed pipe, im using 32mm poly, best is without elbows or any rises and dips.
- regenerative pumps suck well, and tolerate non ideal water sources, but ehy are build with tight tolerances, hence, remember the intake filter.
- need a good foot valve/ strainer. To avoid the pressure loss from an in line strainer, what i use is called a sand filter (that screws onto the foot valve). Its a section of pvc pipe with these micro sized holes in it, its maybe 8 inches in length to get the flow rate. The foot /check valve, whatever you can find that works, the plastic ones seem ok.
- becasue of the volume of water in teh feed pipe, you need a way to prime it without disassembling everything. The pump has a rpime port, but its tiny, and hard to get at. Therefore place a T with a end cap plug near the highest point, but ideally not within 30cm of the pump.
- keep the first 30cm into the pump straight without fittings or bends, to reduce cavitation.
- tighten all the feed fittings with thread seal, and it needs to be as water tight as everything else, otherwise youll suck air into the pump causing it to cavitate.

After that im using one of the cheap chinese pump controllers (no pressure switch), and thats worked out ok so far. Draws about 375W, and is reasonbly quiet if a little whiney at low flows.

My theory is that the lightest foot valve assembly combined with the poly pipe, allows the intake to bend with the flow, this reduces the flood pressure on the assembly. You dont really want to lose it considering teh cost. However when it really rains, the foot valve assembly, sometimes get washed up onto the bank, so you do have to keep an eye on it. The other approach of going totally rigid using galv pipe and brass foot fittings should also work i guess. When ours floods it really floods, comes up about 2m.

You said you need 500 gal per hour. If im running at 900L/hr, then sounds like your going to need at more like 1.5 horse. But Im sure theres folk here who know more about pumps than me.

Sounds like a common jet pump would work for you.