The Preserve Gnarabup group has called on the State government and the Shire of Augusta Margaret River to close the Gnarabup wastewater treatment plant after a report found the plant is leaking contaminates.
Preserve Gnarabup spokesperson Sasha Pol said the May 2021 Department of Water and Environmental Regulation report shows the Government doesn't know the full impact of the pollution from the plant due to poor monitoring.
"What does a sewerage plant leaking contaminants and not complying with its environmental license, just metres from Margaret River's famous beaches say about our clean, green reputation?" Ms Pol said.
She said the report showed the Gnarabup plant is contaminating the surrounding Leeuwin-Naturaliste National Park, Ngari Capes Marine Park and popular Margaret River surf breaks and swimming beaches just metres from the plant.
"The report states nutrients and heavy metals are not being adequately monitored, noting multiple examples of where levels for Nitrate, E.Coli and heavy metals such as Arsenic, Cadmium, Copper, Lead, Mercury, Manganese and Zinc in the ground and close to shore ocean samples exceed expected and acceptable levels set by the Australian and International Standards," Ms Pol said.
"The report sees the department validate many of the concerns Preserve Gnarabup have raised over the past year and the community has been raising since the Plant was built in in the mid-1990s. We call on the State Government and the Shire Council to commit to closing the Plant."
Ms Pol said the department's licensing conditions for the plant required an annual environmental report but the latest document found the last one was done in 2015/16.
"The reporting also does not include historical records or trends prior to 2015/16 and therefore the Plant may have been non-compliant for much longer," she said.
Preserve Gnarabup consulted with scientists which pointed out there was no control bore up stream or to the east of the plant and the downstream bores were limited and not sufficiently widespread.
"These experts are of the view it will take at least 18 months and likely several years before reliable monitoring data is available from the new bores," Ms Pol said.
Ms Pol said the view was backed up by the findings of the new DWER report.
"There is currently a proposal for a development on Gnarabup Headland to increase the volume of waste sent to the Plant," she said.
"Given the problems with the Plant and that fact it has been long non-compliant with its environmental licensing conditions, increasing the waste sent to the Plant would not be environmentally responsible."
Preserve Gnarabup stated the following from the department's report:
"Metals are a contaminant of potential concern associated with treated wastewater. Metals concentrations in groundwater remains a data gap as metals are not included in the monitoring program on the existing licence. Interpretation of metals concentrations in shore water samples was partially limited by the LORs used for the analysis. Chlorophyll a is a condition indicator used to assess the presence of nuisance aquatic organisms such as phytoplankton, cyanobacteria and algae. Chlorophyll concentrations fluctuated between the December and February monitoring events but generally recorded an overall increasing trend during the review period. Point 1 recorded the highest concentrations of the four shore sample points and the monitoring results from this location recorded in February 2019 and 2020 exceeded the default trigger value for inshore marine environments of 0.7 mg/L."
The report includes information showing DWER has considered the Plant as a possible source of contamination since 2017: "Classification: possibly contaminated - investigation required (PC-IR) Date of classification: 20/09/2017"
Further, the report questions whether Plant's operator Water Corporation has provided appropriately located monitoring bores to assess baseline water quality upstream of the Plant.
It repeatedly refers to 'data gaps' and the need to alter monitoring and reporting for the Plant.
"The Delegated Officer considers that additional parameters need to be included in the analytical suite for discharge quality, groundwater quality and shore water quality to address data gaps in the existing monitoring dataset. Updated annual reporting requirements for discharge groundwater and shore water monitoring are also required to provide DWER with adequate information to assess future monitoring results."
AMR Shire Director Sustainable Development and Infrastructure Nick Logan said as the Shire was not the regulator for the Plant, it had no control over ensuring environmental and license obligations.
"The Shire does not have a position on the Gnarabup Resort proposal as a formal application has not been made and considered," Mr Logan said.
"Once an application has been referred to the Shire from the State Government, the Shire will review the application in detail and make a submission to the State Development Assessment Unit accordingly."
