Chippo to become waterfront land this century

The multi million dollar works underway now in Buckland street and continuing through to July right up to the top of the catchment at Darlington are to separate the sewage and stormwater into two pipe systems so they stop mixing and putting over 30 million litres of raw sewage into Blackwattle Bay beside the Fish Markets; the recent rains here produces several million litres of sewage there.

So far so good. In theory.

But this interesting map from New Scientist shows how things might look in 90 years or less - we can expect Chippo to become waterfront land;

http://www.newscientist.com/articleimages/mg20126971.700/1-how-to-surviv...

What happens to sewerage infrastructure like this with a small (say, 150mm) rise in sea level in the next 20 years?

My guess is with a small sea rise the stormwater and sewerage pipes will back up a fair way back into land due to the way the system has a small fall over a large inland hinterland eg Double Bay, Woolloomooloo, Chippendale, etc . . .

If you think this is fanciful then it may help to know that folks used to row by boat from Blackwattle Bay up to Peace Park and watercress used to be harvested from the creek that ran there until Buckland street was put on top of it.

We live in interesting times.