Byron Shire has two Intermittently Closed and Open Lakes and Lagoons (ICOLLs): Tallow Creek and Belongil Creek.
As the Byron Shire has developed and the population has grown, housing has built-up along the coast and within the Belongil Creek and Tallow Creek catchments. The change in weather patterns in recent times and natural processes of these intermittently closed and open lakes or lagoons (ICOLLs) can be at odds with these nearby built environments.
When the mouths of creeks build up with sand (creating a sand berm), water cannot escape and can cause flooding of yards, properties and public infrastructure. The water build up can also create poorer water quality in the creek and lead to odours.
At times, the entrances to Belongil Creek and Tallow Creek need to be artificially managed. What this means and what it may involve include:
- Tallow Creek - scraping the sand bar (beach berm) to promote natural opening of the creek mouth to the ocean with rainfall;
- Belongil Creek - artificially (also referred to as mechanically) opening the creek mouth to the ocean by digging a small channel to allow the water to escape, or flow, to the ocean.
Council manages the entrances to Belongil Creek and Tallow Creek ICOLLs in accordance with licences from:
- National Parks and Wildlife Service (NPWS)
- Department of Primary Industries and Regional Development (DPIRD) - Fisheries (which manages Cape Byron Marine Park)
- Crown Lands
In general, creek entrance management may be necessary when water levels are high to decrease risk of flooding in the catchments.
Collaboration with public authorities and other key stakeholders including Arakwal and environmental groups is important to ensure the values of these creek systems are protected.
Having a flexible and adaptable 'best practice 'ICOLL opening strategy is important to minimise the risks of fish kills.
Belongil Creek and Tallow Creek ICOLLs are natural coastal lagoons. A delicate balance is necessary to seek an opening and closing regime of the creeks as close as possible to natural.
When creeks have been closed for a long time and water inundates backyards and access to walkways are cut, it is understandable that this can be concerning and upsetting and prompts people to call for the sand at the mouth of the creek to be artificially removed.
Meanwhile, other people support natural ICOLL fluctuations and do not want artificial openings to occur at the creek mouth.
Unfortunately, both artificial openings and natural openings sometimes result in fish kills.
Belongil Creek
Council has permission from the NSW Government (Crown Lands and DPIRD Fisheries - Marine Parks) to artificially open the mouth of the creek in accordance with Council's adopted entrance opening strategy. The most recently finalised entrance opening strategy provides flexibility and adaptability.
There are several conditions that must be met for Council to initiate an opening of Belongil Creek in accordance with permissions from Crown Lands and DPIRD Fisheries. The first condition is for the water in Belongil Creek to reach the 'watch level' of 1.0 metres AHD (above sea level). Works can only occur when there is a forecast rainfall of at least 20mm expected to occur within the 24hours following opening.
Tallow Creek
Council has permission from NPWS and DPIRD Fisheries - Marine Parks to manage the entrance of Tallow Creek in accordance with a revised 'Interim Position' of the existing Environmental Management Plan and Opening Strategy. The revised Interim Position was created in response to a fish kill event in June 2019 and subsequent research and consultation and does not support mechanical opening of the creek. Council has permission to scrape the beach berm at the creek entrance down to 2.4m AHD (above sea level) once water levels in the creek reach 2.2m AHD, with concurrence from agencies.
Council may now pre-emptively manage the entrance of Tallow Creek by encouraging 'natural breakout' events of the creek with rainfall.By lowering the beach berm (using an excavator) to allow overtopping during a rainfall event a more natural ICOLL opening event is mimicked, decreasing the potential for a fish kill.
ICOLL best practice management
Best practice management strategies are in place for Belongil Creek and Tallow Creek in the Byron Shire.
The Tallow Creek and Belongil Creek ICOLLs are complex estuarine environments that play an important role in the estuarine and marine ecosystems and the best manager of these systems is nature.
A huge range of complex, scientific factors and issues are assessed before an ICOLL is artificially opened. It is important for people to understand that the following list of issues or conditions DO NOT meet the requirements for an ICOLL opening:
- Low water levels
- Mechanical opening (breaching) in dry weather
- Poor water quality
- Odour
- Public amenity (stagnant water, mosquitoes etc)
Read more about the Environmental Management Plan and Opening Strategy in place for Tallow Creek ICOLL and Belongil Creek ICOLL.
We have an on-going environmental monitoring program associated with entrance management activities for Tallow and Belongil Creeks.
This includes:
- water quality data from equipment located in the creek systems.
- monthly water samples.
- sampling and assessments for any artificial openings of the creeks.
- monitoring of vegetation adjoining the estuaries.
For information about various water quality monitoring programs in Belongil and Tallow Creek catchments visit Coastal Management Programs and view Tallow and Belongil Creek Water Quality Source Tracking documents.
Contact the Coastal Team if you would like a copy of any reports or to talk about our environmental monitoring programs:
Chloe Dowsett