The is an environmentally significant and highly valued riverine estuary located in south-west . Its 19km length stretches from a tidal barrage installed in the year 1898 below the regional city of Geelong BARWON RIVER ESTUARY 2015 and it then flows through a system of to meet the ocean between the popular coastal townships of Barwon Heads and Ocean Grove. The estuary is unique in the Date range: Corangamite region not only for its large size, but also 01/01/2015 – 31/12/2015 because its mouth is permanently open. The system of lakes incorporated in the estuary including Connewarre, , Hospital Swamp and Murtnaghurt Lagoon. These form part of the Port Phillip Bay (Western Shoreline) and RAMSAR site. These lakes provide a wide range of aquatic The constantly changing sand at the mouth of the Barwon River habitats for native fish and birds. estuary. This brochure summarises 12 The estuary is a hotspot for recreation, popular for Type of Estuary: months of EstuaryWatch mouth swimming, fishing, canoeing, bird watching, game hunting, condition and physical and chemical Open Riverine picnicking, walking, motor and sail boating. data. Barwon River EstuaryWatch Location: -38.284329, volunteers monitor 3 mouth condition sites and 5 physical and 144.495908 chemical sites. In 2015 volunteers collected monitoring data for all 12 Nearest town: Barwon Heads months, although not for all sites. Estuary length: 19.1km The Barwon River estuary is a permanently open estuary. The mouth condition River length: 156.6km photos and event photos taken in 2015 reveal a wide range of sand and tidal Threats to the Barwon River Estuary movements at the mouth of the estuary. The salinity results revealed site B1 Mouth state: – Threats linked to urban to be mostly sea water, by site B2 the water becomes more brackish, the most Permanently Open development such as upstream site B6 was mostly brackish with an occasional surface lens of run-off & degradation of native fresher water during times of higher river flow. The only site displaying mild Description: The Barwon River is riparian and estuarine vegetation salinity stratification was the most upstream site B6 during summer. From the major river in the Bellarine June to October salinity levels were lower corresponding with increased river landscape zone. The Barwon River – Altered water regime flows. During 2015 there did not appear to be any flushing freshwater river headwaters are in the Otway – Grazing pressures flows. The dissolved oxygen levels throughout the estuary were maintained in Ranges and it flows over 150kms

– Invasive fauna and flora the healthy range (median of all sites and depths 94% saturation), the lowest through the major regional The dynamic Barwon River EstuaryWatch team level was recorded in the bottom waters at site B6 (56% saturation). The water township of Geelong. The estuary temperature ranged from 8.0°C in August to 23.6°C in January. The pH levels commences downstream of a tidal were also stable throughout the estuary ranging from 7.3 - 8.7 pH units. barrage below Geelong and – Join the Barwon River EstuaryWatch Group EstuaryWatch records at the Barwon River estuary extend from 2007 and can finishes at the town of Barwon www.estuarywatch.com.au be viewed at www.estuarywatch.com.au Heads.

– Register the estuary as a clean-up site for Clean Up Day www.cleanupaustraliaday.org.au – Join a local environment group such as Friends of the Bluff, Ocean Grove Coastcare or the Bellarine Catchment Network www.barwonbluff.com.au corangamite.landcarevic.net.au/ocean-grove The Barwon River EstuaryWatch team undergoing quality control training to ensure the data and information they collect is reliable and corangamite.landcarevic.net.au/bcn accurate. – Share what you have learnt from this annual summary with a friend or family member.

Corangamite Catchment Management Authority 64 Dennis St (PO Box 159) Colac Victoria 3250 (T) 03 5232 9100 (F) 03 5232 2759 Map of the Barwon River estuary, including the location of (E) [email protected] www.ccma.vic.gov.au EstuaryWatch sites. Sourced from Google Maps.

For all four monitoring sessions chosen for the EstuaryWatch Snapshots, photo point photos and a longitudinal profile of the estuary from site B1 (At The Heads Jetty) to B6 (Tidal Barrage) is displayed. The longitudinal profiles show the depth, salinity and percent saturation of dissolved oxygen (DO) at each monitoring site from the surface of the water column to the bottom. Not all sites were sampled on the same day (site B6 was sampled on the later date specified). Photos were also taken on different dates.

Sampled Dates: 05-12/01/2015 Estuary mouth state: OPEN Photo Date: 05/01/2015

Sampled Date: 04-17/06/2015 Estuary mouth state: OPEN Photo Date: 15/06/2015

EstuaryWatch volunteers watch-on as ARI staff conducts fish surveys downstream of the Barwon River lower tidal barrage.

On Wednesday December 2, four members of the Barwon River EstuaryWatch group were treated to an excursion to the Lower Barwon Tidal Barrage. EstuaryWatchers piled Sampled Date: 01-21/10/2015 Estuary mouth state: OPEN into the Corangamite CMA four wheel drive, spotting Photo Date: 30/10/2015 Swamp Harriers and keeping an eye out for the elusive Brolga as they made their way along the Barwon to meet Arthur Rylah Institute staff conducting fish surveys at the barrage. Arthur Rylah set a fish trap for 1.5hrs to determine the fish species using the fish way to move upstream of the tidal barrage. Several thousand juvenile fish were trapped in the 1.5hrs, demonstrating that the fish way is definitely working. Electrofishing was then conducted downstream of the tidal barrage. Sampled Date: 06-09/11/2015 Estuary mouth state: OPEN EstuaryWatchers were most excited to see good sized Photo Date: 25/11/2015 Black Bream, Estuary Perch, Yellow-eyed Mullet and swarms of Toadfish below the tidal barrage.

500 The daily discharge of river 400 water in 2015 recorded at the lower tidal barrage upstream Common Galaxia, Galaxias maculatus 300 of the Barwon River The Common Galaxias adults live in calm waters of low-elevation streams, during autumn they EstuaryWatch site B6. migrate downstream to spawn. Thousands of small eggs are laid in vegetation on the margins of 200 Data source: DELWP at spring tides, and often spend up to two weeks out of water until the next spring tide. 100 Monitoring Station No. The larvae then leave the estuary and spend 5 to 6 months at sea as juveniles before returning to Discharge (Ml/day) 233269 Barwon River U/S the estuary as whitebait moving upstream to the freshwater to mature. 0 lower barrage of Geelong wetlands. See more at: http://australianmuseum.net.au/common-galaxias-galaxias- maculatus#sthash.tCABw6N7.dpuf Photo: Whitebait stage Common Galaxias. Photographer: Rudie Kuiter ©