Geoscience Reference
In-Depth Information
supplies taken from the river for urban and rural
communities. A proposal for such a weir was
formally abandoned in September 2010, but if
one were to be constructed at this location the
salinity of the lakes would increase, as there
would be reduced inflows and limited exchange
with the ocean, and less scope for flushing of
sediments, nutrients and salt (cf. Brookes
et al
.
,
2009; Kingsford
et al
., 2011).
Until river flows resumed after September
2010, management policies in the Lower Lakes
region were focused on a series of isolated,
short-term actions. Under the 'no-flow' scenario,
managers considered that the lakes should be
partitioned into separate hydrological units, to
be managed as different wetland habitats. For
example, Lake Albert might become a temporary,
brackish wetland, and Lake Alexandrina also
could become more saline, with more variable
levels and a surface area perhaps half that of
the present lake. Integration of these and other
proposals into the Long-Term Plan has evoked
community debate over the need for holistic rather
than piecemeal perspectives. From an ecological
viewpoint, the emphasis on rapid deployment of
short-term engineering interventions disrupted
connectivity and could have prejudiced the
capacity of the ecological community for a
sustained recovery. From the government's
viewpoint, the threat of acidification was seen
as unacceptably high (Stauber
et al
., 2008),
subordinating other concerns. The argument
about short-term management responses has lost
much of its intensity following the resumption of
river flows, but drought conditions inevitably will
return, and the basic issues still need to be resolved.
policies. A long-term crisis remains, as flows
are not sufficient for complete recovery (for
example, increased flows are only starting to spill
onto the Lower Murray floodplain in December
2010, later than the seasonal optimum). Climate-
change forecasts suggest a 24-30% decline in
flows at the Murray Mouth in coming decades,
relative to 1895-2004 (CSIRO, 2008). In these
circumstances, a massive reduction in extractions
will be needed, perhaps 42-53% below the present
Cap on diversions (WGOCS, 2010). The irrigation
industry, typically extracting more than 5000
GL yr
−
1
, faces proposed reductions of 27-37%
(MDBA, 2010). Additional funding would be
needed, of course, for social adjustments in rural
communities reliant on irrigation (WGOCS, 2010).
The Guide to the Basin Plan did not consider
the possible benefits of environmental flows above
3000-4000 GL yr
−
1
(MDBA, 2010) and, given
public concern over social and economic issues, it
needs to be emphasized that the proposed flows are
a minimum.
Conclusions
Governments and their agencies were unprepared
for the unprecedented conditions of the water
crisis, especially as it intensified in 2006-2010.
Rapid changes in the environment required rapid
responses, and the partnership between policy
makers, resource managers and scientists was
soundly tested (Kingsford
et al
., 2011). A challenge
for scientists will be to come to a shared
understanding that will allow objective, rigorous
assessments to take their proper place within
the context of community interests (cf. Sarewitz,
2004; Likens
et al
., 2009; Ryder
et al
., 2010). A
challenge for policy-makers and managers will be
to create a more transparent, more accountable
process for science-based policy and decision-
making. The research-management partnership
needs to be exercised as never before. The Murray-
Darling Basin Plan offers a historic opportunity
to
Future prospects
Even with the proposed return of environmental
water to the system, under the Basin Plan, future
management of the Lower Murray may need
to consider 'downsizing' the system, maintaining
some wetlands but sacrificing others, reducing the
floodplain and assisting ecological communities
to adapt to a changing climate. Renewed flows
may have provided some respite, but they come
from good fortune and not better management
include
all
parties
and
implement
a
true,
sustainable
balance
between
resource
use
and
ecological imperatives.
