I want to construct a small stream in my sloping garden. The garden length is about 25 metres, with a drop over that distance of about 50cm. My plan is to build a small stream that is several inches deep and about 2 feet width, lined with small pebbles. The water flow would start from the top of the slope, flow gently down and empty into a natural-looking pond at the bottom of the slope, where the pump would then pump the water back up to the top for recirculating again.

So... what rating of pump will I need to achieve the flow rate sufficient to create a small stream effect?

Advice on this DIY project is much appreciated.

Simon

You would only need the kind of small pump and related equipment like that are used in fountains and other water show pieces. Depending on where you live, you should have no problem finding places that sell that stuff. BUT - in a garden?? Like over dirt? You might want to re-think this one.

The pump must be huge to keep that canal filled with water

I don't see why. We are talking about a flow of water over a distance of 25 metres. If the flow is quite slow then I can imagine the water flow to be in the order of maybe several gallons per minute. So the pump would need to have a capacity of perhaps 500-1000 gallons per hour, not insurmountable when I look at the flow rate from my well pump which fills up my holding tanks - that pumps many gallons per minut up a 50-metre slope.

I think I'll test my 'project' with a similar well pump (non-auto type), and report back.

This might be of some help

ftp://ftp.fao.org/fi/CDrom/FAO_training/FAO_training/general/x6705e/x6705e03.htm

Simon... How about putting in several dams to cause pools? The 20 mm drop per meter is quite a bit as others noted, but the dams with a nice waterfall over the top could limit the water rushing downward and allow you to use a much smaller pump. Just a thought.