The impact of extreme low flows on the water quality of the Lower Murray River and Lower Lakes (Alexandrina and Albert) in South Australia was assessed by comparing water quality from five sites during an extreme low flow period (March 2007-November 2009 and a preceding reference period (March 2003-November 2005. Significant increases in salinity, total nitrogen, total phosphorus, chlorophyll a and turbidity were observed in the Lower Lakes during the low flow period. Consequently, water quality guidelines for the protection of aquatic ecosystems were greatly exceeded. Principal Component Analysis, empirical and mass balance model calculations suggested these changes could be attributed primarily to the lack of flushing resulting in concentration of dissolved and suspended material in the lakes, and increased sediment resuspension as the lakes became shallower. The river sites also showed significant but more minor salinity increases during the extreme low flow period, but nutrient and turbidity concentrations decreased. The most plausible reasons for these changes were decreased catchment inputs and increased influence of saline groundwater inputs. The results highlight the vulnerability of arid and semi-arid lake systems to reduced flow conditions as a result of climatic changes and/or water management decisions.

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Purpose -The purpose of this paper is to examine Australian exporter perceptions of export credit insurance (ECI) value and ECI value drivers to help uncover how Australian (and other) exporters can optimize their ECI use. Design/methodology/approach -This paper uses a 1,000 firm survey of how Australian ECI users and non-users perceive the value of often-cited attributes of ECI and multiple regression analysis to create a model of ECI value drivers. Findings -Most ECI value is derived from the increased trade exporters can manage with ECI protection and from improved access to trade finance. Clear differences are observable in perceived ECI value between larger and smaller exporters as well as between ECI users and non-users. Originality/value -This paper provides the first evidence of perceived ECI value to Australian exporters as well as differences between ECI users and non-users. Export credit insurers and export support agencies need to focus on these differences to ensure that ECI is being optimally marketed and used by Australian exporters.

Large-scale exposure of acid sulfate soils during a hydrological drought in the Lower Lakes of South Australia resulted in acidification of surface water in several locations. Our aim was to describe the techniques used to monitor, assess and manage these acidification events using a field and laboratory dataset (n = 1,208) of acidic to circum-neutral pH water samples. The median pH of the acidified (pH < 6.5) samples was 3.8. Significant (p < 0.05) increases in soluble metals (Al, Co, Mn, Ni and Zn above guidelines for ecosystem protection), SO4 (from pyrite oxidation), Si (from aluminosilicate dissolution) and Ca (from carbonate dissolution and limestone addition), were observed under the acidic conditions. The log of the soluble metal concentrations, acidity and SO4/Cl ratio increased linearly with pH. The pH, alkalinity and acidity measurements were used to inform aerial limestone dosing events to neutralise acidic water. Field measurements correlated strongly with laboratory measurements for pH, alkalinity and conductivity (r (2) ≥ 0.97) but only moderately with acidity (r (2) = 0.54), which could be due to difficulties in determining the indicator-based field titration endpoint. Laboratory measured acidity correlated well with calculated acidity (r (2) = 0.87, acidity present as Al(III) >> H(+) ≈ Mn(II) > Fe(II/III)) but was about 20 % higher on average. Geochemical speciation calculations and XRD measurements indicated that solid phase minerals (schwertmannite and jarosite for Fe and jurbanite for Al) were likely controlling dissolved metal concentrations and influencing measured acidity between pH 2 and 5.