Oral Presentation Australian Society for Limnology Conference 2017

Restoring hydraulic connectivity of a small billabong in an urban context (#29)

Bertrand Salmi 1 , Matthew McClymont 2
  1. Water Technology Pty Ltd, NOTTING HILL, VIC, Australia
  2. City of Greater Dandenong Council, Dandenong, VIC, AUSTRALIA

The health of fragmented indigenous ecosystems in urban areas is declining and water stress is believed to be a key contributor. Fotheringham Reserve in The City of Greater Dandenong contains a revegetated billabong system (EVC Floodplain Riparian Woodland), dependent on streamflows from Yarraman Creek. The hydrological behaviour of this incised urban waterway is likely to have been altered by the recent construction of major road infrastructure and constructed wetlands upstream. Subsequent changes in the inundation regime caused by the land use changes are likely to have contributed to the decline in condition of the billabong vegetation. Further loss may reduce the long-term viability of the billabongs and associated riparian vegetation and facilitate the transition to a terrestrial ecosystem.

A monitoring program is on-going to capture ecological values and key hydrological parameters, including rainfall and water levels, to assist Council in understanding current billabong water regime. The data will be subsequently used to calibrate and validate hydrological and hydraulic models, to assess future inundation frequency. Ultimately, the project will lead to a better understanding of the system and the model findings will inform future management plans for the reserves and its vegetation. This may include identifying possible mitigation measures to reinstate a suitable water regime to restore a healthier billabong, including artificially triggering inundation periods. Or alternatively, it may lead to the conclusion that the changes are irreversible and a “do-nothing” approach is best.

The presentation will provide an overview of results to-date and the management approach considered to restore a more suitable water regime for the billabong.