Possum Valley Water Supply


There are rainwater tanks at both cottages with a single tap near the sink. I suggest that you use this water for drinking and cookingAlthough the tanks are small, they have not yet ever run out.

The water in the rest of the cottage comes from the creek. Being at the top of the Great Dividing Range, we are at the top of the catchment and have first use of the water. Possum Creek starts on the next block and from springs on this block. It is good fresh rainwater filtered through rainforest collecting whatever organic material there may be and is untreated.

The water is pumped from Possum Creek using a No.6 Billabong ram pump. Billabong stopped making them

Ram Pump

20 years ago and the pump is probably 30 years older than that. But with a working life of more than a century, I calculate that it will still be serviceable for 30 years longer than I have to worry about. It is situated 80m downstream of Black Bean Cottage. As it makes some noise, like hammering at heartbeat rate, I try to avoid using it when Black Bean is occupied. I need to pump about 1 day a week if it doesn’t rain. Both tanks also collect rainwater. You can start it if that would amuse you. Go down to the pump and push down the only thing that will move (the clapper valve). To stop, hold it up. How easy was that.

The first ram pump was invented by the Montgolfier brothers in 1792 (of hot-air balloon fame). They used a cannonball for the clapper valve. Not so easy to obtain nowadays. This high-tech device requires no power, using the fall of the creek to drive a water hammer effect. Suddenly stopping the flow of water in the drive pipe causes a pressure spike from the momentum of the water. Whilst the pressure spike is higher than the delivery pressure in the dome, water is forced through a one-way valve, which is a disc of rubber over a plug hole. A recoil effect restarts the cycle.

Using a fall of 3m, it can pump first to the tank by the games room at 22m head. When that tank is full, a ball cock shuts off and the water goes to a tank above Maple Cottage at 45m head. It can pump about 5000 litres a day to the top tank and more to the lower tank.

Next best thing to perpetual motion.

I feel compelled to point out to the scientifically illiterate that perpetual motion does not exist.