The EPA has conducted water quality monitoring in the Port Arthur area since December 2019. The monitoring aims to increase the understanding of water quality within the Port Arthur area.
Water Quality Monitoring Program
The purpose of the program is to provide water quality information to
increase the understanding of water quality in the Port Arthur area and in particular Long Bay
collect data on key indicators for comparison against Default Guideline Values (DGVs) for aquatic ecosystems developed for the Port Arthur area
investigate if any departures from background conditions (DGVs) are attributable to anthropogenic or natural sources and if possible show attribution
provide a summer snapshot for the extent of epiphytic growth on seagrass habitat
provide water quality information to assist nutrient dispersion modelling and biogeochemical model development and validation
independently validate the water quality information collected on a monthly basis by Tassal as required under the environmental licence conditions for lease MF55 (Long Bay Port Arthur).
Default Guideline Values (DGVs) for aquatic ecosystems
Default Guideline Values (DGVs) for aquatic ecosystems have been derived for the Port Arthur Area. The available data from August 2013 to July 2017 has allowed for the derivation of annual and seasonal DGVs of surface, 5 metre depth, integrated depth, and bottom waters for key indicators. For dissolved oxygen, temperature, and pH the 20th percentile represents the lower DGV and the 80th percentile the upper DGV, whilst for all other indicators the 80th percentile represents the DGV. The DGVs are based on the Oil Spill Response Atlas (OSRA) segments and provide a level of refinement over the interim
Default guideline values for Coastal and Marine waters based on the
IMCRA bioregion.
Default Guideline Values for Aquatic Ecosystems Port Arthur - OSRA Segment 79 (PDF 640Kb)
December 2019
The monitoring undertaken in December 2019 aimed to determine point in time water quality across the Port Arthur area, appraise the condition of seagrass habitat and assess opportunistic algal growth levels.
Port Arthur Water Quality Observations December 2019 (PDF 2Mb)
Port Arthur Dec 2019 AST Lab Report (PDF 174Kb)
October 2020 to March 2021
The monitoring undertaken from October 2020 to March 2021 aimed to compare data for key water quality indicators / parameters against Default Guideline Values (DGVs) for aquatic ecosystems developed specifically for the Port Arthur Area. Any departures from the DGVs were investigated to determine if attributable to anthropogenic or natural sources and if possible show attribution.
A snapshot of the extent of epiphytic growth on seagrass habitat was also undertaken with the findings compared to other seagrass habitats across the South East of Tasmania.
Port Arthur Monitoring Results October 2020 to March 2021 (PDF 3Mb)
October 2021 to May 2022
The monitoring undertaken from October 2021 to May 2022 aimed to compare data for key water quality indicators / parameters against Default Guideline Values (DGVs) for aquatic ecosystems developed specifically for the Port Arthur Area. Any departures from the DGVs were investigated to determine if attributable to anthropogenic or natural sources and if possible show attribution.
Three snapshots of the extent of epiphytic growth on seagrass and reef habitat were also undertaken with the findings compared to determine if there was a discernible seasonal pattern.
Port Arthur Water Quality Monitoring Results - October 2021 to May 2022 (PDF 3Mb)
Nutrient Investigation February 2022 to April 2022
An assessment of nitrogen and phosphorus compounds and chlorophyll a levels in Long Bay and the Port Arthur area was undertaken from February 2022 to April 2022. The assessment aimed to investigate nitrogen, phosphorus and chlorophyll a levels whilst the Long Bay finfish lease was stocked and destocked (fallow) across the survey area and in particular within Long Bay.
Port Arthur Nutrient Survey 2022 (PDF 2Mb)
August 2022 to May 2023
The monitoring undertaken from August 2022 to May 2023 aimed to compare data for key water quality indicators / parameters against seasonal Default Guideline Values (DGVs) for aquatic ecosystems developed specifically for the Port Arthur Area. Any departures from the DGVs were investigated to determine if attributable to anthropogenic or natural sources and if possible show attribution. Monitoring of Long Bay Creek allowed for the comparison of freshwater inputs to Long Bay against Site Specific Guideline Values (SSGVs) for aquatic ecosystems of a neighbouring freshwater waterway.
Four snapshots of the extent of epiphytic growth on seagrass and reef habitat were also undertaken with the findings compared to determine if there was a discernible seasonal pattern.
The images selected for analysis for sites SG_PA16 and SG_PA17 are provided below.
Port Arthur Monitoring Results - August 2022 to May 2023 (PDF 4Mb)
Document referred to in the report: SSGVs for aquatic ecosystems of Allans Rivulet (PDF 525Kb)
Epiphyte images for SG_PA16 and SG_PA17 August 2022 to May 2023 (PDF 1Mb)
Fluorometry as a Tool for Assessing Impacts of Finfish Aquaculture – Long Bay and Boomer Bay Study
The EPA is conducting an ongoing assessment of Dissolved Oxygen (D.O.) and Chlorophyll a (CHLa by fluorescence) levels in Long Bay in Port Arthur and Boomer Bay at Dunalley:
To assess the effectiveness of in situ loggers (D.O. and CHLa) as tools for investigating the environmental impact of the finfish lease in Long Bay
To investigate systemic changes in Chlorophyll a levels as reflected by another embayment in South Eastern Tasmania
To assess the feasibility of in situ loggers as a tool for regulating finfish aquaculture.