So, the pond was dug, the concrete rendering was done, the underlay and the butyl rubber liner had gone down, and it was time to start putting the stone into place.
I have to stress that this is an expensive way to build a pond. It's perfectly possible to dig a hole, line it with butyl rubber (use sand and underlay beneath it), put a bit of stone round the edge to make it look pretty, fill it up with water and away you go.
However, I wanted a natural pond, and the problem with putting stone only around the edge is that in order to hide every bit of liner, the stone has to overhang. (Otherwise, in summer when the water tends to evaporate slightly, you can see black liner.) This means it's more difficult for creatures such as frogs to get in and out.
To get around this problem, you can have a gently sloping "beach" area, but because my garden gently slopes both north to south and east to west, it would have been difficult to make this look level while at the same time keeping it stable. It was easier, and looks better, to have shelf areas within the pond, and to cover the liner completely with stone and gravel.
In the picture above, you can see the black pipe that will take the water from the pump to the top of the waterfall.
Here's another view: you can see the black pipe disappearing under the jetty, where the pump is housed. Notice the border of liner around the pond? Read on and you will see how that disappears.
This area to the right of the jetty, with all the gravel, is the reed bed, which will keep the pond water healthy. This works on the same principle as a domestic reed bed sewage system, and although I'm not a freshwater biologist, I'll have a go at explaining how that works.
Reeds are able to transfer oxygen from their leaves down to their roots, which is how they survive in a waterlogged habitat. This creates both aerobic and anaerobic conditions in the soil, which encourages a huge range of micro-organisms to flourish. These micro-organisms break down the waste, and the reeds themselves take up a certain amount in the form of nutrition.
In the past, in smaller ponds, I've used a UV clarifier, but there are lots of reasons NOT to use these. First, if the bulb goes (which it does once a year in my experience), the clarifier stops working - and very often, if you have a modern trip system, the dead bulb trips the fusebox. Not amusing in the middle of winter.
Second, the flow rate has to be just right. If it is too fast, the water passes through the clarifier without being treated. If it is too slow, the algae can reproduce quicker than the clarifier can treat the water.
Third, the clarifier only treats algae - not blanket weed (or string algae). Fourth, a UV clarifier uses electricity, and while it doesn't cost that much in the great scheme of things, I feel a bit guilty about using power when I don't need to.
It seemed to me much more sensible to have a eco-system that would look after itself and create a healthy habitat for pond life naturally.
Now that the top of the waterfall area has been lined in stone, it's beginning to look as if it has always been there. The idea was to replicate a natural stone "outcrop" on the slope. Here's Rufus making one of his regular tours of inspection here. I had no idea he was such an expert on landscape architecture.
The jetty is finished! I suspect this will be everyone's favourite place to sit come next summer. You can see how the stone has been laid to hide the edge of the liner, and also hide the pump under the jetty.
This gives a better view of how the waterfall comes down into the pond. The guys have laid the stone following the lines of the rock strata, which also helps it look natural.
It had taken eight days of work to get to this stage, and the build schedule was 10 days in total. It was time to start thinking about plants - and I'll tell you about that in my next post.