Coastal science and the Murray River mouth

Two important documents about the River Murray were released last week (23 Jan and 2 Feb.).  First, the Murray-Darling Basin Royal Commission completed its report investigating the operations and effectiveness of the Murray-Darling Basin system.  Second, on World Wetlands Day a new book about the Coorong, Lower Lakes and Murray Mouth was launched.

 These are both significant as the coastal area around the Murray Mouth is at the ‘end of the drain’ for Australia’s largest river catchment.  The Royal Commission notes, “It is now more likely that warnings are sounded, and heeded, that ‘rivers die from their mouths’ ”.

 A major finding of the Royal Commission was that the Murray-Darling Basin Authority and the Minister, “must … act on the basis of the best available scientific knowledge’ (para 21(4)(b))” …. but that this “has most regrettably not been consistently obeyed (see Chapters 3, 4, 5, 7, 9 and 10)”.

 It appears that the Murray-Darling Basin Plan has neglected the best available science in terms of coastal issues around the Murray Mouth. Unfortunately, the Royal Commission report doesn’t focus on this point even though it did receive relevant submissions and representations.  The Commission even incorrectly quotes 1980 as the year when the Mouth closed whereas it actually occurred in April 1981. The Commission’s report is available online.

 In an attempt to provide good science for the region, The Royal Society of South Australia produced a book on the Natural History of the Coorong, Lower Lakes, and Murray Mouth Region.  This is available as a free PDF download (about 160 MB) from the University of Adelaide Press.  For convenience, smaller files of sections of the book can be downloaded here: Introduction and Part 1; Part 2a Part 2b; Part 3; Part 4 and references.

 The book, launched last Saturday by the SA Environment Minister along with river advocate Gloria Jones and family, covers landscape evolution over millions of years, the retreat of the Ngarrindjeri as sea levels rose since 18,000 yrs ago, through to modern flora and fauna and management issues.

 The book had five editors, numerous contributing authors and 26 separate chapters.  Of particular relevance for coastal management are chapters 2.2 on the evolution of the River Murray Estuary and 2.3 on the Mouth of the River Murray.

What is important about these two documents is that they both emphasise the need for good science behind environmental management.  This is particularly important for the Murray Mouth where a costly and unsustainable dredging operation is attempting to keep the ‘end of the drain’ open in response to a problem largely created upstream.

Words by Prof Nick Harvey. Please respect the author’s thoughts and reference appropriately: (c) ACS, 2019, posted 6 February 2019, for correspondence about this blog post please email austcoastsoc@gmail.com