Waterway and catchment Report Card 2024
Reporting on data November 2023 to April 2024
Results 2024
This year five sites had improved ecological health driven by improvements in the algal growth grade (Coolongolook, Karuah and The Branch Estuaries, Bombah Broadwater and Charlotte Bay).
Four sites received worse grades for water quality than 2023 due to higher levels of algal growth (Mid Wallamba Estuary, Wallamba Cove and Farquhar Inlet), or short-term impacts to water clarity from large rain events (Khappinghat Estuary).
Overall rainfall was slightly below average over the 2023-24 sampling season, however above average falls occurred in October and February.
Manning River Estuary
The Upper, Mid and Lower Manning Estuaries remained in good condition for the third consecutive year. Water clarity remained good, and the algal growth was fair.
Farquhar Inlet returned to good condition this year, its usual state, with excellent water clarity and low levels of algal growth.
The Dawson River Estuary, Browns Creek, Ghinni Ghinni Creek and Lansdowne River Estuary all remained in fair condition. This was driven by algal growth highlighting the need for more catchment management actions in the catchment to reduce nutrients in runoff.
Khappinghat Estuary
The Khappinghat Estuary returned to good condition this year. Water clarity was excellent and there was very low algal growth for the majority of the sampling period. The change from an excellent to good grade this year was driven by very high turbidity in the estuary following a large rain event in February which temporarily impacted water clarity.
Charlotte Bay returned to excellent condition this year due to a reduction in algal growth. Higher algal growth in recent years led to a drop in grade from the excellent standard that was recorded from 2011-2019.
Wallis Lake and Pipers Creek retained their good grade this year due to excellent water clarity and generally low levels of algal growth.
Coolongolook Estuary improved to good condition this year, the result driven by less algal growth and good water clarity.
Mid Wallamba Estuary and Wallamba Cove were both in fair condition this year due to a poor grade for algal growth in both estuaries. Water clarity remained excellent in Mid Wallamba Estuary and good in Wallamba Cove.
Overall grade This represents ecological condition, it is a combination of algae and water clarity scores.
Seagrass depth range score: The seagrass score indicates how deep the seagrass is growing and if the seagrass area is expanding or contracting. Where there are no seagrass results, no data was collected at these locations. Historical grades
For more details on the scientific methods and results contained in this Report Card (Waterway and Catchment Technical Report) www.haveyoursay.midcoast.nsw.gov.au/waterway-report-card
Karuah River and The Branch Estuary
Karuah River and The Branch Estuaries improved to good condition this year due to less algal growth and good water clarity. Moderate levels of algae persist resulting in a fair grade for algal growth.
Smiths Lake
Smiths Lake retained its good grade this year. The lake entrance was closed for the summer leading to water from catchment runoff remaining in the estuary from longer. Higher levels of algal growth were recorded compared to last year. Algal growth was in the good range and excellent water clarity was maintained throughout the sampling period.
Myall Lakes
Myall Lake was in excellent condition for the sixth consecutive year while Bombah Broadwater returned to good condition due to improved water clarity and less algal growth.
Salinity in Myall Lake was close to freshwater and was lower than the salinity in Bombah Broadwater, which is typical for these waterbodies.
Lower Myall Estuary was in good condition, with excellent water clarity and low levels of algal growth for most of this year.
Protecting our estuaries
Estuaries are where freshwater from our rivers meets salt water from the ocean. They are an important environmental zone, brimming with a diversity of life.
The Southern Estuaries of the MidCoast region, including Wallis, Myall and Smiths Lakes, Karuah River, North Arm Cove, Kore Kore and Khappinghat Creeks and Black Head Lagoon are some of its greatest assets. They strengthen the MidCoast economy, they are some of the reasons our community love where they live, and others come to visit.
MidCoast Council are continuing work on a Coastal Management Program (CMP) for its Southern Estuaries. This program will set the direction for the future of our estuaries and help MidCoast Council and State Government identify, understand, prepare for, and respond to current and emerging pressures on these estuaries.
Building our knowledge to inform future management
Studies to guide the actions in the Coastal Management Program are now complete (Stage 2). Studies included an assessment of the extent and condition of coastal wetlands, potential impacts of tidal inundation and risk assessments for Khappinghat Creek and Black Head Lagoon.
The results of these studies are now being analysed and they will be used to assist in identifying potential management actions to help protect our beautiful estuaries over the next ten years.
The Southern Estuaries Coastal Management Program will include actions to support the environmental, economic, social and cultural values of our estuaries.
Creating a strong program
The best way to protect our estuaries is to develop a strong management program, guided by scientific evidence and community values.
Working with our community, other government agencies and scientific researchers the aim of Stage Three is to identify as many management options as possible that can potentially be implemented over the next ten years.
These options will then be presented and open for comments from all interested parties in early 2025.
Have your say
Don’t miss the opportunity to be involved! Keep up to date with the program by signing up on our website: www.haveyoursay. midcoast.nsw.gov.au/ oursouthernestuaries.
The science of our systems
Estuaries are valuable environmental assets that are under increasing pressure. A large number of MidCoast residents live within and rely on our waterways.
Results from monitoring and scientific studies combined with local knowledge and expert advice help Council determine where to put effort to have the most effective approach to managing our waterways.
How important are Oyster Reefs?
Oyster reefs are important ecosystems that are linked to the health of fish stock in our waterways. However, they are heavily impacted by human activities and globally 85% of oyster reefs are in decline.
The Wallis Lake and Manning River estuaries have both seen declines in shellfish reef extent and condition.
Researchers from the University of the Sunshine Coast utilised underwater cameras to survey fish distribution across the estuary but also in specific habitat areas like remnant oyster reefs, seagrass, saltmarsh and mangroves.
The intent of these surveys was to establish if there is a need to restore oyster reefs for fish and fisheries within the region. This information about fish distributions was used to identify potential oyster reef restoration sites which would have the greatest potential to maximise fish biodiversity, abundance and fisheries values.
Where do mangroves grow and why?
Mangroves are an essential habitat within the MidCoast’s coastal zone. They provide many benefits, including riverbank protection, improving water quality and providing a habitat for fish. Have you ever wondered why mangroves grow in one spot but not another or how they might adapt to climate change?
Researchers from University of New South Wales have been figuring out what influences mangrove distribution by undertaking field surveys and examining their tidal inundation patterns. The aim is to improve our understanding of mangrove environments so we can predict restoration outcomes or project their response to sea level rise. Their results indicate that mangroves are resilient and can adapt to various environments. Furthermore, determining mangrove distribution requires considering a mangrove’s lifecycle and the estuary dynamics. Their findings will help guide future mangrove and other coastal habitat management decisions.
What’s hiding under Wallis and Smiths Lakes?
Wallis and Smiths Lakes are biodiversity hotspots, however prior to the early 2000s sponges and ascidians had rarely been studied in these lakes.
Over the last 20 years MidCoast Council in partnership with scientists from the Universities of Wollongong and Western Australia have undertaken surveys across numerous sites in both estuaries. Since monitoring began in 2002, 4 species of sponges have been recorded in Smiths Lake, and 11 species of sponges have been recorded in Wallis Lake, many of which are likely to be new to science.
Additionally, sampling showed a pattern of boom and bust highlighting the complexity of these systems and how they can possibly be influenced by impacts from development and environmental conditions such as drought, floods and fire.
Access to these long term datasets can help us monitor changes in our estuaries and inform management for these special species.
This project is funded by MidCoast Council’s Environmental Allocation and supported by the New South Wales Government through it’s Coast and Estuary Program and Department of Climate Change, Energy, the Environment and Water.