The last couple of weeks in May brought a flurry of activities.  First, a long expected meeting of numerous agencies concerned with the health of the Macleay River, then the Clybucca Wetlands Paddle.

Click here for a full report of the meeting. Macleay River Working Group 24th May 2018

What to Do on the Clybucca?

At an event hosted by SOMR and sponsored by North Coast Local Land Services, 55 paddlers went up the Clybucca Creek System on 26th May to explore and be informed of the environmental problems and a range of potential solutions.
A research and community engagement project is currently being undertaken on the Clybucca Floodplain, following a successful funding application for $365,000 under the NSW Department of Primary Industries (DPI) Flagship Fish Habitat Grants Program. The project, submitted by North Coast Local Land Services (LLS), will deliver a remediation strategy, complete with engineering design options to improve water management across the floodplain.
It will aim to neutralise acidic conditions across a large area of Mayes and Doughboy Swamps, improve freshwater wetland condition, and rehabilitate estuarine habitat. It will also aim to improve the drainage of productive grazing land throughout the Clybucca – Collombatti floodplain.
North Coast Local Land Services – Senior Land Services Officer Max Osborne said a key component of the project is community engagement. The Water Research Laboratory at the University of New South Wales (UNSW-WRL) has been engaged to prepare the strategy and the aim is to ensure all stakeholders’ concerns are addressed.
“Over the next 12 months, North Coast Local Land Services and UNSW-WRL will be working closely with landholders on the Clybucca floodplain, Seven Oaks Drainage Union, Kempsey Shire Council, NSW Government agencies, community groups, the Aboriginal community, industry, and academics to ensure we get the best outcomes for the region,” he said.
What’s the problem?
Over drainage of coastal wetlands has created problems with acid sulfate soils, causing sulfuric acid runoff; and has also increased the frequency and magnitude of “blackwater” events, depleting oxygen in the creeks and river after flooding. This has unfortunately had wider impacts on the estuary, including the loss of fish habitat and impacts to aquatic life, such as fish and oysters in the Lower Macleay. This impacts the environment, the local economy, recreational and commercial fishing, traditional usage and tourism.
What caused this problem?
The Clybucca sub-catchment has undergone hydrological change over time. At one time, it was covered by the sea and had slowly filled in by the sediment eroding from the upper Macleay catchment. In the late 19th century the area was a freshwater wetland. However, the marine mud (high in sulfur) lay below the wetlands sediment.
Tidal restricting barriers, flood gates and extensive drainage networks have lowered surface and groundwater levels and exposed the marine muds (naturally occurring acid sulphate soils) to oxygen—resulting in the acidification of topsoil, groundwater, in-drain water and ultimately, the Macleay estuary. (Osborne 2018)
Over-drainage has allowed flood-intolerant grass species to dominate where previously only wetland-adapted species thrived. During floods, these grasses are inundated for several days. They die and rot—depleting the floodwater of oxygen. This hypoxic (no oxygen) blackwater then drains into the Macleay estuary, which damages the aquatic ecosystem. (Osborne 2018)      Over-drainage has allowed flood-intolerant grass species to dominate where previously only wetland-adapted species thrived. During floods, these grasses are inundated for several days. They die and rot—depleting the floodwater of oxygen. This hypoxic (no oxygen) blackwater then drains into the Macleay estuary, which damages the aquatic ecosystem. (Osborne 2018)
Russell Yerbury, a former beef producer from the Clybucca Floodplain and Max Osborne from North Coast Local Land Services discussed the issues and some of the potential solutions being investigated as part of the remediation strategy project.
SOMR would like to thank Max and Russell for their commitment to improving the health of the Macleay, and for supporting the Clybucca Wetlands Paddle. We would also like to thank the participants in the paddle and encourage community to be informed and participate in this crucial decision impacting the future health of the Macleay River.
Wetlands Australia 2018 https://www.environment.gov.au/system/files/resources/b0f30409-2d92-4ec6-a57d-35e59b765be0/files/wa30-full.pdf Pg. 35 – 36 relate to the Clybucca Wetlands
Blackwater Fact Sheet http://www.environment.gov.au/system/files/resources/c6a83595-14ef-4d82-8db3-0aec0a172b64/files/cewo-blackwater-factsheet.pdf
Wetland Pasture https://www.dpi.nsw.gov.au/__data/assets/pdf_file/0003/405696/Water-couch-growth-and-productivity.pdf

Click here for a video created by Elsinor Photography showing the Paddle.    https://www.youtube.com/watch?v=RoOsH7G3koY

In the evening after the Paddle on the Macleay, people gathered at the Stuarts Point Community Hall to learn more about the wetland restoration in the Lower Macleay.

During the day, while at the Golden Hole, NPWS Ranger Penny Kendall had already given a potted history of the area and the reasons behind the re-inundation. (See the previous post about the Paddle.)

In the evening, the appreciative audience listened to long term resident Lindsay Brackenbury (96) who expanded on the history of the Yarrahapinni area and the wetlands with an indigenous and non-indigenous perspective.

Rupert Milne Home, event organiser and ex-Chair of the Yarrahapinni Wetland Reserve Trust, and Penny Kendall gave a good insight into the difficult and lengthy process of negotiation by the Yarrahapinni Wetland Reserve Trust and later National Parks and Wildlife Service before tidal flow could begin. The land effected by acid sulphate soil and the water in the area responded almost instantly to the inundation with saltwater. Click here to read more about  The Yarrahapinni Wetlands Story

Considering the surprising speed and extent of the recovery, they concluded that it is now necessary to address the restoration of other wetlands such as the Clybucca.

The last speaker of the day was Oyster Grower Todd Graham. He gave an excellent insight into the interrelation of the ecosystems and the effects on the oyster industry:

In May 2014 the Macleay River Oyster Farmers Environmental Management System (EMS) was launched. In the EMS the highest external risk identified was Low pH/Acid Sulphate Soil (acidic water released through disturbance or drainage of acid sulphate soils). This acidic water has changed the Clybucca Harvest Area from a highly productive area to an area that the oyster farmers rarely use. The acidic water bleaches he shells of older oyster and it will kill younger oysters by dissolving their shells.

In late January 2015 this acidic water combined with low DO in the water caused a major fish kill. Any oysters that were in the Clybucca Harvest Area had to be moved to one of the other harvest areas. The continuation of a successful oyster industry in the Macleay will depend on the restoration of the wetlands in the estuary.

The Macleay River Shellfish Quality Assurance Program formally supports the Clybucca Floodplain Rehabilitation Project which is attempting to determine the best practice management options to improve the water quality emanating from the Lower Macleay floodplain landscape. This project is being headed by the Clybucca Working Group.  Click here to read about the Macleay River Oyster Farmers Environmental Management System

All the speakers agreed that the restoration of the wetlands in the Lower Macleay needs the support of the community.

SOMR is preparing a public event for early 2016. Scientists from the University of New England are going to present their latest research results in the Macleay River catchment. We also anticipate a presentation about the Clybucca Wetlands.