Having filled the pond up, we had a few minor(!) crises when we realised that:
1. we hadn't dug the stream out properly
2. we hadn't put the waterfall stone in
3. Himself was convinced the side walls of the pond were about to collapse at any minute
4. we had got a large amount of water lapping up against where we needed to work
NOT one of our better moments!
Himself had an "it's all doomed" moment and I had a major hissy fit, resulting in a brief but loud rant at poor old Himself along the totally non-PC lines of "thick people build ponds, it's can't be SO difficult, what IS your problem?!!!". I did apologise very profusely later on.
I then set about emptying the pond with a trug and chucking all the water on the veg patch. Himself, being the more sensible less volatile one, built a temporary holding tank on the lawn and drained the water into that instead until the water level was down to shelf level.
We bought some plastic coated corrugated panels (meant for roofs, I think), cut them to size, used a plank to fold the liners over and clear where we needed to work then put the pond sized panels in place and back-filled with soil.
Himself then built a wall to rest the waterfall stone securely on. The poor love tried so hard to put straight lines into the pond, all of which I refused to have and promptly removed on the grounds that natural ponds don't have straight lines. His wall was the only straight bit in the whole pond - and it got covered up once the mortar was dry - but he was happy because he knows it's there!
I got busy digging out the route for the stream. The group of rocks in front of me with my red sweatshirt on are the island. The stream route meanders between the island and all the other rocks behind me. No straight lines for me!
The Nutty Gnome mid-action.
Himself putting the waterfall stone in place. We had aquired the stone from a friend's garden. It looked great because it had been shaped by something/someone to have a gentle sloping curve in the middle - ideal for water to trickle over and look like it had worn the stone away over the millenia. It was taken in and out several times to get the height and levels perfect. Unfortunately, on one move, it was accidentally dropped and cracked in half down the middle. Himself was mortified.
I went to the local stone yard and scrambled about on their rejects pile until I found the perfect new waterfall stone - for a quid! (A quid is £1 or approximately $1.60). Bargain!