I've been looking for a while at scenery kits to create ponds from and I think GW latest releases does the trick The old craters they used to produce were pretty good but not available anymore. Last week Skaven Gnawhole kit provides a good base. They really quick to put together if you don't use all the woody bits. I might try to do them without the spiral effect in the water next time. I've also painted regular Skaven Gnawholes. All available in the shop.