Just in case you didn't know Bob, the Hazelwood Pondage is heated as it is the main cooling for the Hazelwood power station. At the outlets - which are off limits to the public - the temp is very high, but by the time it reaches the public area - the main part of the lake at the top end via a channel, it's around 30, then drops to around 22 to 24 at the very end by the time it reaches the overflow. There's a cooler to make the water temp more 'victorian' by the time it reaches the outer waterways.
You can swim comfortably in it in the middle of Winter - we use to as kids all the time. :)

