Lower Barwon Wetlands

The Barwon River rises in the Otway Ranges and flows through Geelong, joining the ocean at Barwon Heads. It includes significant inflows from major tributaries, including the Moorabool and Yarrowee-Leigh Rivers, which rise in the Victorian Central Highlands region of the Great Dividing Range.

Prior to entering the sea, the Barwon River drains through a large estuarine zone comprising a lake and wetland complex including Lake Connewarre, Reedy Lake, Hospital and Salt Swamps, Murtnaghurt Lagoon and the Barwon River estuary at the river mouth.

The wetlands are connected by various degrees to the Barwon River and/or Lake Connewarre, which lies centrally in the complex.  These wetlands form part of the internationally significant Port Phillip Bay (Western Shoreline) and Bellarine Peninsula Ramsar Site.

The wetlands consist of a diverse range of aquatic vegetation communities, providing important feeding and breeding habitat for native fish and a number of wetland-dependent bird species, including a number of rare and endangered flora and fauna.  It is a culturally significant area for Wadawurrung Traditional Owners. Culturally sensitive areas persist as it has long been a place of sourcing food and artefacts.  Within the Lower Barwon Wetland Complex, environmental water can be actively delivered to and from Reedy Lake and Hospital Swamps, which lie within the Connewarre State Game Reserve managed by Parks Victoria.

A flow ecology investigation was undertaken by Lloyd, et al. in 2012 to identify the most appropriate watering approach for Reedy Lake and Hospital Swamps based on maintaining the ecological character of the wetlands. The Lower Barwon Review, conducted in 2020 to review the adopted watering regime, supported the wetting and drying regime with the advice to initiate a gentler, more evaporative draw down at Reedy Lake. In addition, it recommended going no lower than 0.3m AHD if possible and using bird monitoring information to inform the timing and rate of draw down.

The watering regime at each wetland should be considered as a whole. All watering actions, whether they be wetting, drying or connecting flows contribute to a balanced ecosystem.

Reedy Lake

Reedy Lake’s biodiversity includes 16 ecological vegetation communities (EVCs), such as coastal saltmarsh, herbfields, sedgelands, open water (semi emergent/macrophyte communities) and reed beds, which all play an important role in providing habitat diversity for a variety of flora and fauna species.

Maintaining the ecological character of the wetland requires a balance between these vegetation communities. Wetting and partial drying regimes produce a mosaic of different habitat types as the water availability fluctuates providing specialist habitat for a wide variety of different flora and fauna to utilise. Productivity at wetlands adapted to a wetting and drying regime, such as Reedy Lake, is driven by the disturbances caused by fluctuating water levels, occasional periods of high water and occasional periods of very low water.

The findings from the flow ecology investigation (Lloyds et al, 2012) recommended that the lake’s watering regime be modified to include more regular lowering of water levels to restore the site’s threatened ecological values. The recommended watering regime is a four-year water cycle, which includes low water levels over summer for 3 years, and a full water level in the fourth year (Figure 6). All four years include a full water level in winter. These recommendations have been subsequently supported by two further independent expert reviews.

Hospital Swamps

The Hospital Swamps ecosystem has retained its ecological character and biodiversity values predominantly due to the regulated management (by graziers and others) of the natural wetting and drying regime since the 1970s (Lloyd, et al. 2012).  

Lloyd, L.N., Cooling, M.P, Kerr, G.K., Dahlhaus, P. and Gippel, C.J., 2012. Flow/ecology relationships and scenarios for the lower Barwon Wetlands environmental entitlement

Since the entitlement was established in 2011, the CCMA has continued to implement the historical wetting and drying regime.  Variable climatic conditions over the past seven years have also provided a level of seasonal fluctuation in conditions, which provides additional environmental benefits to existing watering activities (i.e. floods, fresh events and extended drying events).

As a consequence, the wetland’s internationally significant waterbird population and diversity has been maintained and the diverse ecological vegetation communities have remained largely unchanged since the 1980s. The water regime of Hospital Swamps is seen as currently beneficial to the ecosystem values of the site (Lloyd, et al. 2012). The environmental values of the wetland are in good condition, supporting large areas of threatened subtropical and temperate coastal saltmarsh and a diversity of fish and waterbird populations. The recommended watering regime for Hospital Swamps is to continue the wetting and drying regime below, nine out ten years. In the tenth year, it is recommended to maintain the wetland dry or shallow flooding all-year round .

Lower Barwon Wetlands Community Advisory Committee

The Lower Barwon Wetlands Community Advisory Committee has been established to provide feedback on planned water management in the Lower Barwon Wetlands from a community perspective. The committee will provide an honest and open environment for concepts, issues and knowledge to be shared in a safe and collaborative environment.