There was a wildlife cameraman on Countryfile this Sunday who has a pond at the bottom of his garden. He lowered his camera into the water and showed us frogs, newts, water spiders, dragonfly larvae- even fish. If you make a pond, water-loving creatures will sniff it out and move in.
The cameraman's pond is an artificial construct, specially excavated with a plastic bottom inserted, but we already have a stream going through our land- a tiny trickle of a streamlet- and I reckon that all I need to do is dam it and a pond will form. It's what beavers do- and they're the experts. The area I've selected is almost a pond already. It's very marshy and there are water flags growing in the sludge. In fact I think it must have been a pond once. You can tell from the way the channel widens into a roughly circular depression. And the quantity of brick and building stone that is scattered around suggest it was either a dump (which is one of the things ponds are good for as one knows from detective fiction) or there was some sort of structure there- a sluice gate perhaps. So I won't so much be making a pond as restoring one.