This may not be what you mean, but my allotment slopes away from our dip tank, so I have a handy length of hosepipe to set up a syphon with. I pour water from watering can into the hose until I think it's enough, then plunge the end into the tank with my thumb over it, and weigh it down with a brick (tied on with string).
If all goes well, it pours slowly out of the distant end, and I can water the beds with it.