2023 sandbar opening
Thursday 29 June 2023
On Thursday 29 June 2023 at about 10am, Nullaki (Wilson Inlet) was opened. The water level was approximately 1.27 mAHD at the time of opening. By Friday 30 June, the outgoing flow had scoured the bar to a width of about 100 m. About 27 GL of water was discharged into the ocean in the first 24 hours after opening.
The channel was cut approximately 100 m from the western cliffs’ reference point.
Imagery of the opening was captured by Department of Water and Environmental Regulation staff members, Cassie Paxman and Alex Burgoyne.
2022 Sandbar
Most years the Nullaki (Wilson Inlet) sandbar is manually opened to the ocean to prevent flooding of low-lying land. In 2021, the sandbar was opened on Monday 21 June.
The water level was just under 1.5m AHD (1.3m above sea level). Due to deep channel formation, ongoing river flow and ocean conditions, the channel between the inlet and the ocean did not close over summer.
This is the first time on record that the channel remained open for the entire year. The Department of Water and Environmental Regulation has captured the state of the sandbar over the last year using a drone.
2021 Bar opening
Monday 21 June 2021
On Monday 21 June 2021, Wilson Inlet was opened after having been closed for only three and a half months. The last time the inlet was opened this early was 16 years ago. The early opening occurred after more than 100 mm of rain fell over the Wilson Inlet catchment within 24 hours. This caused the water level to rise by 30 cm within 10 hours. The water level was just under 1.5 m AHD (1.3 m height above sea level) – the highest since records began in the 1950s – when the inlet was opened.
The channel was cut approximately 100 m from the western cliffs’ reference point.
By Tuesday 22 June, the outgoing flow had scoured the bar to a width of about 150 m.
About 30 GL of water was discharged into the ocean in the first 24 hours after opening. However, because large amounts of water were still entering the inlet from the catchment, the water level took four days to drop to about sea level.
Imagery of the opening was captured by department staff member, Alex Burgoyne. Poor weather limited aerial filming on the day of opening.
2020 Bar opening
12:30pm Thursday 13 August 2020
In 2020, the Wilson Inlet bar was opened by dredging a channel between the ocean and the inlet. The inlet water level at the time of opening was 1.17 m AHD (1.01 m height above sea level) and the channel was cut approximately 100 m from the western cliffs’ reference point. Approximately 6 GL of water was discharged to the ocean in the first 24 hours after opening.
The outgoing flow scoured the bar to a width of approximately 40 m by Friday 14 August.
Using a drone, Cliff Ford captured footage of the inundation of land along Ocean Beach Road before the bar’s opening, the opening itself and discharge of the inlet’s water into the ocean.
2018 Bar opening
12:00pm Thursday 23 August 2018
In 2018, the bar was opened by dredging a channel to the ocean with two openings into the Inlet. Storm events in July 2018 caused large amounts of sand to be dumped onto the sand bar making it unusually large compared to recent years.
The inlet water level at the time of opening was 1.07 m AHD and the channel was cut approximately 100 m from the Western cliffs reference point. Approximately 13.5 GL of water was discharged to the ocean in the first 24 hours post-opening.
The outgoing flow scoured the bar to a width of approximately 100 m by Friday 24 August.
The Inlet height, the opening, impact on the bar and ocean discharge was captured with a drone by Ash Ramsay (Department of Water and Environmental Regulation, South West region).
2017 Bar opening
12:30pm Thursday 24th August 2017
In 2017, the bar was opened by dredging a channel to the ocean at an Inlet water level of 1.27 m AHD and 100 metres from the Western cliffs reference point.
This was the highest bar opening since 1978 which had an estimated elevation of 1.25 m AHD at the time of opening.
Approximately 27 GL of water (~14 per cent of the Inlet volume) was discharged to the ocean in the first 24 hours post-opening. The volumetric flow rate was recorded as 210 m³/s on the Friday at 2 pm. The high water level and strong flow effectively scoured the bar to a width of approximately 150 metres.
The Inlet height, the opening, impact on the bar and ocean discharge was captured with a drone by Ash Ramsay (Department of Water and Environmental Regulation, South West region).