❓ Question addresses water quality concerns in the Vasse River, Busselton, focusing on phytoplankton levels, dredging, and Phoslock use. The answer provides details on existing plans, budgets, monitoring locations, and results, as well as future plans.
AnsweredQoN 1856Legislative Council
QuestionView source ↗
I refer to the Vasse River as it flows though Busselton, and I ask: (a) what plan does the Government have in place to improve the water quality in the Vasse River; (b) what budget does the Government have in place to improve the water quality in the Vasse River; (c) is the Government measuring the level of phytoplankton in the Vasse River; (d) if yes to (c), in what locations is the testing occurring and at what frequencies; (e) please table the results of the testing in part (c) for 2021, 2022 and 2023; (f) to which Government department(s) is any testing from part (c) being reported; (g) are these reports made publicly available; (h) what dredging has been done in the Vasse River to improve water quality and what dredging is planned in the future; (i) how is the success of the dredging being measured; (j) how much phoslock has been used in the river and how much is planned to be used; (k) how is the success of the use of Phoslock being measured and please table those measurements; (l) has any used Phoslock been removed from the river; and (m) how many toxic algal or phytoplankton blooms have been recorded in the Vasse River in 2021, 2022 and 2023?
AnswerView source ↗
Answered
12 March 2024
Responded by
Parliamentary Secretary to the Minister for Water
Response time
4 days
(a) The Vasse Wonnerup Wetlands and Geographe Bay Water Quality Improvement Plan (2010). In addition, the multiple agency Vasse Taskforce coordinates water quality improvement actions in the Vasse Geographe catchment including the Lower Vasse River.
(b) The Revitalising Geographe Wetlands project budget has been around $1.6 million annually since 2015. The specific budget on the Lower Vasse River varies annually depending on remediation works undertaken.
(c) Yes.
(d) Fortnightly at three locations (upstream of Bussell Highway, downstream of Strelly Street Bridge and downstream of the Causeway Bridge).
(e) Data below are summarised by both biovolume which relates to the guideline and cell counts which relate to the actual number of phytoplankton cells counted in each sample.
Please note VASR1 is Vasse river 1 measuring site, which is located downstream of Strellly St and upstream of the Causeway bridge. VASR2 is Vasse River 2 measuring site at the footbridge between the Causeway bridge and Camilleri St. Data from the third measuring site was not included due to no algal or phytoplankton bloom activity.
Year
Site
Total Cyanobacteria Biovolume (mm 3 /L)
Winter Minimum
Summer Maximum
2021
VASR1
0
93
2022
VASR1
0
47
2023
VASR1
0.01
171
2021
VASR2
0
134
2022
VASR2
0
34
2023
VASR2
0
183
Year
Site
Total Cyanobacteria Counts (cells/mL)
Winter Minimum
Summer Maximum
2021
VASR1
94
810,000
2022
VASR1
25
5,000,000
2023
VASR1
148
1,800,000
2021
VASR2
32
690,000
2022
VASR2
34
6,200,000
2023
VASR2
47
1,700,000
(f) Department of Health and the City of Busselton
(g) No.
(h) Stage 1 and 2 dredging undertaken by the City of Busselton in 2022 and 2023 with Stage 3 proposed for 2024.
(i) Water quality monitoring in the river.
(j) Forty tonnes of phoslock has been applied to the Lower Vasse River over two periods in November and December 2023.
(k) Water quality and phytoplankton monitoring.
(l) Phoslock is not removed from the river once it has been applied. The phoslock remains in the sediment where it can continue to bind phosphate.
(m) In each of those years there has been an ongoing blue-green algae bloom lasting several months over summer. It is not practical to divide this continuous presence into separate blooms although the species composition changes over time in response to changes in supply of nutrients, light, temperature and salinity change.
(b) The Revitalising Geographe Wetlands project budget has been around $1.6 million annually since 2015. The specific budget on the Lower Vasse River varies annually depending on remediation works undertaken.
(c) Yes.
(d) Fortnightly at three locations (upstream of Bussell Highway, downstream of Strelly Street Bridge and downstream of the Causeway Bridge).
(e) Data below are summarised by both biovolume which relates to the guideline and cell counts which relate to the actual number of phytoplankton cells counted in each sample.
Please note VASR1 is Vasse river 1 measuring site, which is located downstream of Strellly St and upstream of the Causeway bridge. VASR2 is Vasse River 2 measuring site at the footbridge between the Causeway bridge and Camilleri St. Data from the third measuring site was not included due to no algal or phytoplankton bloom activity.
Year
Site
Total Cyanobacteria Biovolume (mm 3 /L)
Winter Minimum
Summer Maximum
2021
VASR1
0
93
2022
VASR1
0
47
2023
VASR1
0.01
171
2021
VASR2
0
134
2022
VASR2
0
34
2023
VASR2
0
183
Year
Site
Total Cyanobacteria Counts (cells/mL)
Winter Minimum
Summer Maximum
2021
VASR1
94
810,000
2022
VASR1
25
5,000,000
2023
VASR1
148
1,800,000
2021
VASR2
32
690,000
2022
VASR2
34
6,200,000
2023
VASR2
47
1,700,000
(f) Department of Health and the City of Busselton
(g) No.
(h) Stage 1 and 2 dredging undertaken by the City of Busselton in 2022 and 2023 with Stage 3 proposed for 2024.
(i) Water quality monitoring in the river.
(j) Forty tonnes of phoslock has been applied to the Lower Vasse River over two periods in November and December 2023.
(k) Water quality and phytoplankton monitoring.
(l) Phoslock is not removed from the river once it has been applied. The phoslock remains in the sediment where it can continue to bind phosphate.
(m) In each of those years there has been an ongoing blue-green algae bloom lasting several months over summer. It is not practical to divide this continuous presence into separate blooms although the species composition changes over time in response to changes in supply of nutrients, light, temperature and salinity change.
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