- Dwarf Galaxias are threatened by habitat loss and altered flow regimes. Climate change poses an additional threat with lower streamflows and loss of wetland habitat, particularly drought refuge pools. Dwarf Galaxias persist in Cardinia Creek, despite historical catchment impacts, and rapid urbanisation. Melbourne Water is committed to protecting the species, and managing urbanisation-related threats. Their existing retarding basin site presented an ideal opportunity to create additional, connected habitat in the system.
- We designed a wetland habitat using a multidisciplinary approach, incorporating:
- Required habitat and wetting/drying regime assessment
- Hydrological modelling of potential creek and stormwater inflows to create required wetland habitat and variable water regime, considering seepage and evaporation.
- Design of wetland size, depth and location to create hydrological habitat; variable depths, extensive shallow areas and deeper, permanent pools.
- Innovative engineering design; inflow pit and pipe sizing for correct inflows, gravel traps to prevent predatory fish ingress, and creek outflow structure.
- Recommended vegetation plantings in 6 distinct zones from permanently inundated to riparian.
- The existing site proved ideal for wetland habitat creation; stormwater provided suitable inflows, and outflow to the adjacent creek system maintained hydrological function. Creation of refuge pools within the wetland mitigates climate change risks for the existing creek population.
- This project highlights opportunities to create habitat at existing sites, providing multiple benefits and mitigating threats of urban development, altered stream hydrology and climate change. The robust technical methodology can be applied at any site, and delivered inexpensively. The project provides a model for management of similar threats elsewhere.