Yellagonga Regional Park wetlands groundwater monitoring 2016/17 report
Document Type
Report
Publication Title
Mine Water and Environment Research/Centre for Ecosystem Management Report No. 2017-4
Publisher
Mine Water and Environment Research Centre
School
School of Science
RAS ID
46839
Funders
City of Joondalup
City of Wanneroo
Abstract
In 2012, MiWER completed a review of available groundwater data for the area surrounding the Yellagonga Regional Park. It identified the paucity of information relevant to management of the Park. In response, the City of Joondalup installed two bores on the eastern side of Lake Goollelal. In August 2012, MiWER commenced a groundwater monitoring program utilising the new bores and existing bores that were best located to gain an understanding of groundwater impacts on the Yellagonga wetlands. In 2014, two further bores were provided at Neil Hawkins Park and Ariti Avenue by the Cities. In 2016/17, monitoring of bores was reduced from monthly to bimonthly. Monitoring involved measurement of groundwater height, physico-chemical parameters, nutrient concentrations and selected metal/metalloid concentrations. Three bores were located on the eastern side of Lake Joondalup, two on the western side. Wallubuenup Swamp had one bore sampled on its eastern side and one on the western side. Two bores were sampled on the eastern side of Lake Goollelal and one on the western side. A total of ten bores throughout Yellagonga were sampled. This report covers monitoring from June 2016 to May 2017. The bores on the western side of the park show an increase in conductivity and related parameters in late summer, following evapo-concentration of solutes in the lakes. Ratios of sulphate to chloride and sulphate to alkalinity indicated the possible presence of ASS contamination at N.E. Goollelal, W. Wallubuenup, S.E. Joondalup and Mid E. Joondalup, although pH was not < 5 or aluminium concentrations > 1 mg L-1, these sites had some very high iron concentrations. Overall the likelihood of ASS contamination of these bores has increased since 2015/16. Metal concentrations such as Al, As, and Zn exceeded ANZECC & ARMCANZ (2000) guidelines for the 95 % protection of aquatic systems by up to an order of magnitude (10 times) on occasion. Concentrations of Al were however not at levels indicative of active ASS, although Fe concentrations were very high on occasion. The groundwater should continue to be monitored to keep a watch out for possible ASS problems which might necessitate management action. It appeared that groundwater was a source of Al and Zn identified in the wetlands. High concentrations of P and N were recorded in a number of the eastern bores (particularly Mid E Joondalup), suggesting groundwater is an important source of nutrients into the northern end of Lake Joondalup. Concentrations of P appear to have increased since 2015/16, although the distribution over time and between sites was very similar. Concentrations of N appear to have decreased slightly although lower organic N has been replaced with higher concentrations of the more problematic NOx. Key recommendations from the study are to continue monitoring at the current frequency as this appears to be striking a balance between detail and cost. A new bore is proposed for the eastern side of Lake Goollelal to assist in identification on nutrients entering the lake.
Access Rights
free_to_read
Comments
Gonzalez Pinto, J., Lund, M.A., & Quintero Vasquez, M. (2017). Yellagonga Regional Park wetlands groundwater monitoring 2016/17 report. Mine Water and Environment Research/Centre for Ecosystem Management Report No. 2017-4, Edith Cowan University, Perth, Australia. 36pp. Unpublished report to the Cities of Joondalup and Wanneroo.
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