Yellagonga Regional Park wetlands water quality monitoring 2016/17 report

Abstract

Kinnear, Garnett et al. (1997) undertook a fifteen month study of the Yellagonga Park wetlands and concluded that they were eutrophic (enriched with nutrients) as a result of natural processes within the system and anthropogenic inputs. Lund, McCullough et al. (2011) and more recently Newport and Lund (2013) have confirmed acid sulphate soils present in the southern section of the park and metal contamination of wetlands in the Park. In the second, third and fourth years of monitoring Newport, Lund et al. (2011), Newport and Lund (2012), Newport and Lund (2013) reported that ANZECC/ARMCANZ (2000) water quality guidelines for the protection of aquatic systems were being exceeded for some physical parameters, nutrients and metals throughout the park’s surface waters.This report covers monitoring of the Yellagonga Park wetlands as per Newport and Lund (2013) for June 2016 to May 2017.All parameters recorded were compared to the ANZECC & ARMCANZ (2000) national water quality trigger values for the 95 % protection of aquatic ecosystems. In 2016/2017 water quality was improved compared to previous years with only limited exceedances of guideline concentrations over slightly fewer elements (Al, Cd, Hg, and Zn).Sulphate to chloride and sulphate to alkalinity ratios suggest that there are acid sulphate soils within the catchment, but that natural buffering within the system is preventing low pH and high metal concentrations. The low rainfall in 2015/16 did not result in metal release and obvious acidity in 2016/17. Despite this, there does appear to be an ongoing trend of lower pH across the entire system as recently reported in DOW monitoring.Recommendations from this report include supporting ongoing monitoring of the wetland system and further studies to improve management of water quality