Heike wrote: Tell us a bit more, Treegod!
I think originally it was just for water storage, and it has a stream flowing into it. That's where the silt comes from and the creatures too. Later some people put ladders onto it and it's more a swimming pool now. We clean it by emptying it in the winter or spring. We can't empty it in summer because there are risks of forest fires.
We've got water boatmen, they bite though I've managed to avoid it. There are tadpoles, which yesterday I saw being hunted by a snake whilst I was hunting the snake with nets. Then there are lots of dragonfly and damselfly larvae. There are clouds of little creatures that I don't know that hang around the bottom of the swimming pool, but I don't know what they are.
As for vegetation there is a little growing from the bottom but not much. And the water is a bit greenish because of the algae, but it's pretty clear.
It's also quite cold, there's no heater connected to it, except for the sun, and even then it's never warm. But I've been getting acclimatised to it