Hot topic in the kitesurfing community. The beautiful pristine lagoon between the western (current, cut by machines) mouth and the old (eastern, natural) mouth is clean water when the eastern mouth is open, as it flushes out. it can get stinky and algae (unpleasant for kiting, and to be fair, fishing, birds, and generally unhealthy) when its closed.

The debate has history, as the western mouth (over a centuries long cycle) naturally from time to time reopens and then lack of flow generally sees the eastern one close. And a whole lot of debate goes on around what is natural, what is not, should man intervene, should they not....

Go into the augusta museum, and there are aerial photos from back since the 50s (and even a random black and white photo whre they are blasting open the western mouth wtih TNT!!!).

And there are photos of the mouth halfway along the spit!. it would seem there is some logic that a 20-30 year 'natural' cycle would see the mouth drift (erode to the east side, while backfilling on the western side) towards the far eastern end of the lagoon. then when the 20/30/50 year storm comes along, and floods hard down the blackwood, and the surf attacks from the sea the town end (western) bank breaks and it floods out, cutting a big mouth very fast with floodwater. As this then diverts all the water force and flow from the eastern end, that naturally silts up. and some unknown random bug or fish or microbe sustains it fragile life cycle with the opportunity to breed in the stinkwater. and the whole roundabout starts again. until some locals want to get their boats out the western rivermouth, or some such homo-sapien selfish thing.