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RERP Gwydir

The Gwydir Wetlands are a mosaic of remnant wetland types hosting rare, endangered and vulnerable species and large populations of migratory birds. A total of 823 hectares are listed under the Ramsar Convention for Wetlands of International Importance. Retaining the ecological character of these representative wetland areas is an obligation under the Convention.

Historically, the Gwydir Wetlands covered an area of over 220,000 hectares, with less than 15% now remaining. Factors such as land development, river regulation and weed invasion have resulted in a loss of wetland habitat and a decline in the health of semi-permanent and ephemeral wetland communities over a number of decades. It has also lead to fewer bird breeding events and a reduction in fauna that inhabit the wetlands.

RERP action

Increasing the environment’s share of available water

At the end of May 2011, RERP had purchased 14,902 megalitres (ML) of general security access and 441 ML of supplementary access water entitlement. Combined with the Australian Government’s Environmental Water Holdings a total of 375 ML of high security, 104,427 ML of general security and 19,099 ML of supplementary access water is available to the environment, in addition to the environmental water available under the Gwydir Water Sharing Plan.

New Gwydir Wetlands State Conservation Area

In January 2010, RERP funded the purchase of the 4292-hectare private property Old Dromana for inclusion in the NSW reserve system. This purchase secured the protection of what was the largest (600-hectares) privately owned portion of the Gwydir Wetlands Ramsar site. The property, of which 2000 hectares is wetland, supports:

• a remnant stand of marsh club-rush, which is currently under-represented in the NSW reserve system and is listed as a critically endangered ecological community under the NSW Threatened Species Conservation Act 1995;
• the habitats of rare, endangered and vulnerable species and migratory birds listed under international treaties with China, Japan and the Republic of South Korea; and
• large areas of coolibah floodplain wetland (part of the Coolibah–Black Box Woodland endangered ecological community).

Monitoring of environmental flows

A surface-water gauge was installed at the end of the Lower Gwydir watercourse to enable real-time monitoring of environmental flows reaching the Ramsar wetlands on Old Dromana.

Managing water hyacinth in the Gingham watercourse

RERP has developed a partnership, in conjunction with local landholders and the Moree Plains Shire Council, to control water hyacinth across more than 1000 hectares of the Gingham section of the Gwydir Wetlands. Controlling this NSW-declared noxious weed will improve water quality, support the re-establishment of native wetland vegetation and allow environmental water to be used more efficiently.

Conservation on private wetlands

Incentives have been provided to landholders to improve the management of 152 hectares of wetlands located on private property. This includes the fencing of wetlands on Belmont, Bunnor and Whittaker’s Lagoon to control grazing and support native wetland flora and fauna.

 

Community engagement activities

A number of community engagement events were held in the Gwydir Wetlands, including several field days on wetland plants and grazing management within wetlands. As a result of these activities, several wetland graziers are adjusting watering points, fencing layouts and grazing practices in support of wetland values.

Fish passage solutions

RERP has funded the design of fishways at four major regulating structures at Tyreel Weir and Regulator, Boolooroo Weir and Tareelaroi Weir. The resulting detailed designs and business case presents a ‘shovel-ready’ capital works opportunity. When constructed, these fishways will connect the Barwon River to Copeton Dam and provide free fish passage through 350 kilometres of river system. State Water has subsequently committed funding to commence construction of Tyreel Weir Fishway and is examining options to progress Boolooroo Weir Fishway.

Gingham domestic pipeline and restoration project

The Wetland Recovery Program and RERP funded a $2.9 million project to replace the man-made open Gingham Channel previously used for stock and domestic water delivery. The project, including the installation of 240 kilometres of new pipeline, 65 tanks and three pumping stations, will provide for the efficient delivery of water to households and reduce water losses from evaporation and infiltration. Water savings resulting from the project, (958 megalitres of High Security water) will be used to support wetland assets within the Gwydir.

Complementing the pipeline project, RERP invested $285,000 in restoring the natural function of the Gingham watercourse. The initial works, completed prior to the 2010-11 season, resulted in water flowing to wetland areas that have not been well watered since 1998. As a direct result of reconnecting old flow paths, a number of key wetland bird species were attracted to the newly watered areas and successfully fledged their young. Further works have been completed and are likely to restore over 3000 hectares of core wetlands.

The area benefiting includes Ramsar-listed wetlands, historical colonial waterbird breeding sites, Endangered Ecological Communities and critical habitat for core native wetland species.

 

Research to better understand complex wetland ecosystems

A number of research projects have been undertaken to compile:

• vegetation community condition and extent mapping;
• the recent history of inundation in the Gwydir Wetlands; and
• relationships between the response of key species and the delivery of environmental flows delivery.

Hydrodynamic and hydrological modelling tools

A hydrodynamic model has been developed showing how water moves through the Gwydir wetlands. The model will assist water managers in targeting environmental flows in support of wetland health. Using information from the hydrodynamic model, a hydrological modelling tool has been developed to link the Gwydir Wetlands to the catchment hydrology model used to manage water in the Gwydir valley. The hydrological model represents the effects on the wetland from changes to infrastructure, regulation practices, dam operation rules and climate change over the short and long-term (over 100 years).

Decision Support System

The development of a Decision Support System (DSS) for the Gwydir Wetlands brings together scientific research to support a transparent and scientifically rigorous decision-making process. The DSS integrates ecosystem response models with hydrological models, allowing for the comparison of scenarios relating the volume and timing of water delivery to ecological outcomes. This tool as it develops over time will assist water managers optimise the use of environmental water and sustain the identified ecological values of the wetlands.