The artificial opening of the Belongil Creek, an Intermittently Closed and Open Lake and Lagoon (ICOLL), on Monday, 12 October led to yet another significant fish kill with locals and vistors advised to avoid the area and not swim nearby.
Community members are calling on Byron Shire Council (BSC) and other associated bodies to ‘explain why the opening was considered necessary, what operational maintenance it facilitated, which works were completed, what alternatives were assessed and how the ecological risks were evaluated,’ said concerned local Kelly Minahan.
In a press release by BSC at the time they said, ‘For several weeks a buildup of sand at the mouth of the creek was causing inundation in low-lying parts of Byron Bay and Belongil, with water filling stormwater culverts and drains and covering some pathways.’
This prompted them to manually open the creek in line with BSC’s adopted Entrance Opening Strategy and Environmental Management Plan, which led to the fish kill.
Development vs ecosystems
‘Under natural conditions the estuary mouth is frequently blocked by sand deposited from longshore transport and onshore winds, sometimes for long periods. Naturally allowing water to build up behind the barrier to somewhere between 1.8 and 2.4 metres above mean sea level before being breached in a storm event,’ ecologist Dailan Pugh explained in a December 2021 report on fish kills.
‘A conflict now exists with residents in upstream areas that are subject to nuisance flooding of their land when the estuary is full. The problem is that people are opening the Tallow Creek estuary, or forcing Council to, during dry weather conditions, without rainfall events sufficient to bring fresh oxygenated water into the estuary, and are causing major fish kills.’
In 2014, 2017, and 2019, Tallow Creek experienced serious fish kills as a result of artificially opening the ICOLL.
Pugh said in his report that the result of the 2019 opening of the ICOLL ‘was that 12.4 tonnes of dead fish were taken to the tip, many tonnes were washed out to sea, and innumerable small fish and fingerlings were killed’.
Was opening needed?
In the report Pugh assessed results from the five BSC testing sites across the Belongil estuary looking at the oxygenation levels of the water and stated that, ‘These results support the theory that it is decanting of oxygenated surface waters in the estuary when it is opened without sufficient rainfall inflows, combined with drainage of toxic waters from upstream into the estuary, that are the principal cause of the observed fish kills.’
Minahan and other locals are asking the question if the intervention was necessary.
‘Approximately one week after Belongil was artificially opened, the Northern Rivers experienced the very conditions that nature needs to mobilise these coastal systems: actual heavy rainfall and a significant easterly swell,’ he told The Echo.
‘These conditions could have raised lagoon levels and enabled a natural opening, potentially avoiding the intervention and its associated ecological consequences.
Investigation
‘This is not about ignoring legitimate flood risks or community safety. It is about demanding compelling evidence before intervening, properly assessing alternatives, understanding catchment conditions and ocean swell, and allowing natural processes to operate wherever safe and practicable.
‘Did we intervene unnecessarily, just days before nature could have done the work for us? That is the question Council must answer.’
‘It’s not the result we had planned for; no one likes to see a fish kill and Council and government departments are investigating and reviewing the incident to inform opening protocols,’ a BSC spokesperson said.
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