Manning Valley Region
Acid Sulphate Soils
33,797 hectares of land within the Manning Valley has been identified as being affected by potential acid sulfate soils (ASS). 4,500 hectares has been identified as ASS hot spots by the NSW Government.
ASS are sediments naturally occurring in estuarine and floodplain areas, which were once high in organic matter (such as old mangrove forests and other wetlands).
These sediments occur below the water table and when left in place are not a problem. When removed from a waterlogged state, such as during excavation or as a result of drainage (lowering the water table), these sediments oxidise and the passage of water through the material creates acid run-off or leachate that can contaminate surface and ground water.
In addition to the acid nature of the water, it also carries increased levels of aluminium and other metals, which can be toxic to aquatic flora and fauna and those species living in bottom sediments. The impact on fish stocks and oyster production can be significant.
We have undertaken a very successful ASS restoration project at Cattai Wetlands and have begun another restoration project at Big Swamp.
For those wanting to develop land that may be affected by ASS and require planning advice, we have prepared a fact sheet(PDF, 62KB) to help you.
For more information about ASS visit the NSW Primary Industries website.
Our beautiful Manning River and its tributaries have long been havens used by visitors, holiday makers, locals, oyster farmers and anglers.
The Manning River is one of only two deltas in the southern hemisphere with two river entrances, the main entrance at Harrington and the second at Farquhar Inlet, just south of Old Bar. The Manning River is a complex estuarine system which includes a number of branch creeks and channels.
There are a number of public ramps, wharves, pontoons, riverside parks, commercial tourist destinations and towns and villages scattered along the river.
The following documents have been prepared to guide the management of the Manning River estuary:
Farquhar Inlet entrance opening management plan
The Farquhar Inlet is situated at what is considered to be the southern entrance of the Manning River. Concerns regarding the water quality at Farquhar Inlet and the associated state of the local oyster industry were raised by the community during the consultation phase of work that was undertaken by Patterson Britton & Partners (now WorleyParsons) in preparing the ‘Manning River estuary management study’ (GTCC, 2009).
It is understood that frequent and extended closures of the oyster harvest areas in recent years have led to a reduction in the profitability of the shellfish industry. In addition, the condition of water quality at Farquhar Inlet is seen by the community to impact on the recreational value of the lower estuary in the vicinity of Old Bar and has a potential impact on tourism.
The Manning River Estuary Management Study acknowledged these issues and the concerns of the local community. The 'Estuary management plan" that was developed from the study identified the need for further investigation and the development of an Entrance opening management plan for Farquhar Inlet(PDF, 22MB).
Council engaged WorleyParsons to undertake these investigations and to develop the plan. The plan documents the current situation and the issues surrounding the current management of the entrance. It also describes and assesses a range of options that could be implemented to manage the entrance so that the frequency of the water quality and recreational issues that have occurred over recent years is reduced, and provides recommendations for the future management of the entrance.
Manning Estuary, Coastline & Catchment Advisory Committee
The Committee is independent of Council and has representatives from different government and community groups. The committee meets quarterly.
The purpose of the committee is to;
- Provide a forum where members can raise issues relating to coastal zone management in the Greater Taree area, and that relate to potential catchment issues impacting upon the coastal zone.
- Provide a forum where members can seek input, guidance and support for activities relating to coastline and Manning catchment management.
- Monitor progress of activities outlined in the Manning River Estuary Management Plan and Coastline Management Plans prepared by Council.
- Provide a forum for information and feedback on the review or formation or key plans and strategies relating to coast, estuary or catchment management by any agency.
- Facilitate an understanding amongst committee members of current and future potential coastal zone issues.
- Coordinate an advocacy role where required, that member organisations may present a united argument on local issues. Representation on issues will be made by unanimous vote of the committee only.
- Respond to relevant legislative changes.
Provide current information on estuary, coast and catchment management issues to the wider public via the mechanisms of Committee members, and a Committee web page to be hosted by Council.
Manning River maintenance dredging strategy
Dredging of the Manning River estuary commenced in the 1850s to clear a channel from Harrington to Wingham which continued until the 1940s. More recently the need for dredging certain reaches of the river to improve navigation and environmental flows have been identified in the 'Farquhar Inlet Old Bar entrance opening management plan' and the Manning River Estuary Management Plan.
The Manning River maintenance dredging strategy(PDF, 11MB) was adopted by Council in August 2010 and last updated in 2015. The Strategy prioritises dredging within the Manning River estuary so that it is sustainable over the long term. Some 27 dredging sites have been identified ranging from extreme to low priority. The Strategy provides a historical context to dredging in the estuary and provides information on the estuary processes, which result in the need for dredging.
The Strategy also outlines the steps necessary in the planning and implementation of dredging works as well as the legislative requirements, indicative extraction volumes and costs, and potential funding sources. The Strategy essentially provides a strategic framework to assist in the application for funding to achieve maintenance dredging works that have been identified.
Manning Wetlands Steering Committee
Wetlands are important natural assets of the Manning Valley. They impact the health of the environment and the productivity of our aquaculture, fishing and tourism industries.
The Committee was established to help us meet the following objectives:
- Encourage and facilitate the restoration and retention of coastal wetlands and adjacent lands in Greater Taree to improve their ecological value.
- Protect and improve the water quality of the Manning River, with a focus on reducing runoff from acid sulfate soil areas.
- Promote the importance of wetlands and acid sulfate soil remediation within the community.
The Committee played an important role in the Cattai Wetlands and the Big Swamp Project.
We have prepared a guide to help you in undertaking foreshore management works including riverbank restoration.
The guidelines provide information on the legal obligations of landholders as well as other planning considerations that need to be taken into account before undertaking foreshore management works.
They also highlight the opportunities available for landholders to seek technical support and government funding to undertake these types of works.
State of the Manning report card
The health of the Manning River estuary is in fairly good condition according to the State of the Manning Report Card(PDF, 840KB).
The report card summarises the results of a water quality monitoring program undertaken in the Manning River estuary during 2013/14.
Receiving an overall grade of B has placed the Manning River in the top half of all estuaries in NSW in terms of ecological health.
During the preparation of Council’s Environmental Action Plan, the community identified the health of the river as one of the most important environmental issues in the Manning Valley. However, in order to effectively manage and protect the river, we need to first have an understanding of its health and condition. A greater understanding of the health of the estuary will assist us and other land managers to identify and target areas where further investigation and action is required.
The report card has revealed that while overall the estuary is relatively healthy, bouts of poor water quality were experienced in the mid to upper zones of the estuary, particularly following rainfall. Poor water quality can be characterised by high turbidity levels and excessive algae growth. Turbidity in the Manning occurs as a result of sediment laden runoff from areas where vegetation has been removed and the soil is exposed, and from gravel roads and eroding riverbanks; whereas high levels of algae are caused by stormwater runoff that contains nutrients from urban areas and farmland, and from cattle accessing the waterway.
We have undertaken a number of projects to address poor water quality in the Manning River including riverbank stabilisation works at Glenthorne and Wingham, where the banks have been revegetated with native plants and rock fillets have been constructed to protect the banks from erosion and to allow the re-establishment of mangroves.
The health of the Manning River is such a high priority for the local community, 50% of all funding raised through the environmental levy has been allocated to projects that achieve improvements in water quality and estuarine health. This funding will enable us to implement many of the actions contained within our Estuary Management Plan(PDF, 9MB) including the continuation of the water quality monitoring program for the Manning River. This is the first year of what is intended to be a long-term approach to tracking the health of the estuary and identifying any obvious trends.
The project was made possible with matching funding provided through the NSW Office of Environment and Heritage’s Estuary Management Program.