For the technically minded
Designing a garden ponds is never particularly easy so this is my solution which seems to work as required. Essentially, I have two ponds that feed each other via stream. One pond is about two meters above the other and about 14 metres apart.
It was clear from the start that I would have to use at least a pipe of 1.5" diameter and after looking at many manufacturers I decided I need a substantial pump if I was going to achieve a reasonable flow rate in the stream. In the end I picked a pump capable of providing a flow of 150 litres/minute at the height needed to be pumped in my garden.
I eventually selected the Oase Nautilus 12000 together with their remote controller which enables me to reduce the flow (I normally do not run the pump at full flow). The Oase site contains some interesting pages that will help you decide which pump you will require for your particular circumstances.
I bought the pump, pipe, controller, liners and other bits and pieces from Water Garden: http://www.water-garden.co.uk who I can highly recommend as being very, very helpful.
This is something you will never see unless you
go to look at a pool! Pump running at 25%
Pump running at 100%