Jennifer Marohasy

a forum for the discussion of issues concerning the natural environment

To Dredge, or Not to Dredge

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ABC Online is running two stories on dredging.

One is about dredging at the mouth of the Murray, see http://www.abc.net.au/news/newsitems/200508/s1428180.htm

In this story, Brenton Erdmann from South Australia’s Water Department is quoted stating that dredging has made a big difference, “We’ve been dredging continuously for 24 hours, seven days a week for coming up to three years now so we’re really starting to see the benefits of that.”

I am not sure from the piece what the benefits are.

Interestingly, when Charles Sturt arrived at Lake Alexandrina (bottom of the Murray) in 1830 what we now consider the Murray’s mouth was back then a maze of impassable sandbars.

The other story is about Melbourne’s Port Phillip Bay and how a flotilla plans to blockade the entry of a dredging ship on the basis dredging will destroy marine life in the area, see http://www.abc.net.au/news/newsitems/200508/s1427699.htm.

So it’s good to dredge the mouth of the Murray, but bad to dredge Port Phillip Bay?

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Comments

  1. Bob James says

    Dear Jennifer: I have had trouble getting an email delivered to you. Address trouble? maybe this will find you.

    First thank you for your most informative address. it was good to hear some sensible, unbiassed comment.

    Secondly I was mosdt pleased to meet you and Joam – I am so pleased you brought her along.

    I note your interest in GM.. I imagine this is a debate where you can throw some sensible light. maybe youm can address us one daya on this?

    re the River Murray mouth. What was it like BEFORE the locks were built I spent a lot of time, as a kid, in school holidays, with my Dad. THis was pre-war. The lake shores of Alexandrina and Albert prior to the Goolwa barrahges, had no fresh water bullrushes growig on the shores and shallows. The ingress of salt water in drought killed then off.

    When driving along the Murray above Morgan, Dad used to show me numerous places where he could drive across the dry riverbed. Obviously in dry times, before the upstream locks were built, post WWI.

    So the River had numerous periods when there was no outflow at the mouth.

    Ther is a very interesting factual history of the Murray-Darling system from the very early days of settlement. Try to get a copy of “Riverboas” by Ian Mudie. I had a c copy in about the mid-1930s. Recently loaned it but did not get it back!

    Kind regards and again many thanks. Bob james.