Lake Alexandrina vs Goolwa Channel
5 August 2010
By Ian Rowan
Comment on Request for Reconsideration of EPBC/4833
I consider that the request to allow additional pumping from Lake Alexandrina into the Goolwa Channel should not be granted at this stage.
The objective to establish connectivity for fish migration is admirable and warranted but it is considered that this could be accomplished by other means rather than deprive the Lake from much needed water.
Since the beginning of winter, the water level in the Goolwa Channel has risen 0.3m to +0.2m AHD as a result of approx 180mm of local rainfall. Now that the catchment is saturated there should be sufficient rainfall in the next 2 months (average 90mm) to raise water levels in the Channel above 0.3m AHD said to be by the proponent the minimum required height to allow the Barrage to be partially opened and achieve connectivity without deleterious effects. If this is the case then all the objectives specified by the proponent will be met by local runoff only.
The salinity of water in the Goolwa Channel currently ranges from 18,000 to 21,000 EC units between Clayton and the Barrage to less than 5000 10km up the Finniss River. Even if some limited mixing of sea and brackish Channel water were to occur in the vicinity of the Barrage there will still be more than sufficient diverse fresher water environments available further upstream.
Furthermore, I consider that any decision to allocate water now that the MDBA report has been deferred would be seen as callous by all other prospective users especially if there were alternative possibilities.
I regret the short period given for public comment but consider that the request to pump additional water be not allowed at this stage as it is reasonable to assume that local inflows would in the interim be sufficient to meet the connectivity objectives.
PS Even as I review this comment we have now received locally a further 7 to 10mm of rainfall which will raise the Goolwa Channel water level further.