Climate change, monsoonal lows and storm surges combine into a deadly concoction for the low lying area of Elwood. Two major Integrated Water Management Projects are underway in the Cities Bayside and Port Phillip, with Glen Eira forming the Elster Creek water catchment to address this and other integrated water management issues.
The duplication of the Elwood main drain is intended to further protect Elwood from flooding whilst the work underway in Bayside will further develop the outstanding achievements of the Yalukit Willam Nature Reserve.
The project aimed at flood mitigation is the partial duplication of the existing diversion drain which currently runs underground from New Street to the outfall at Head Street. The new works will duplicate the diversion drain from St Kilda Street to the Head Street outfall. It is aligned with a second project: the Yalukit Willam wetland project Stage 2 which will act as an additional water retention basin during flood events whilst supporting the completion of the wetlands.
- Construction start date for the duplication of the diversion drain Project of mid 2025 with completion date in 2 years’ time under the management of Melbourne Water.
- No timeline available for the Yalukit Willam Nature Reserve (YWNR) Stage 2 work under the management of Bayside CC.
Both of these projects have been a long time in development representing the first serious re-consideration of the problems of flooding in the Elwood area since the devastating floods in 2011 and a near miss flood event in 2016. The two initiative proposed represent the greatest benefit to mitigating flood damage especially when climate change impacts are factored in.
Current flood mitigation measures for Elwood/ Bayside already operate with a significant part of Elsternwick Park sports fields acting as a large retarding basin in floods and the existing underground drain from New Street to the Bay, diverting water from the Elwood area.
Over the past 10 years Melbourne Water has convened advisory committees with community representation and local Council Committees (Port Phillip, Bayside and Glen Eira). Whilst the intention was to see upstream solutions to flood events, current proposals aim to make improvements largely within Elsternwick Park (Bayside). Numerous reports and investigations for upstream solutions proved insoluble due to the high levels of impermeability in the 41 square kilometre catchment and the high cost associated with remedies in this area.
The two projects now being considered aim to maximize the potential of the last area of open space in the Catchment. Both projects include flood mitigation in their design; however the drain duplication diversion project will only operate during a major flood event.
On the Yalikut Willam Nature Reserve, or northern side of Elsternwick Park, new wetlands are being designed for construction by the City of Bayside in the Yalukit Willam Nature Reserve as part of Stage 2 of this world leading nature reserve. These wetlands are much deeper than the already constructed chain of ponds and will serve multiple purposes consistent with Integrated Water Management Principles.
In storm event conditions : The wetlands in the stage 2 project will assist in flood mitigation by operating as a flood retarding basin designed to drain down over 12-24 hours following a storm event. The only water remaining in the Yalikut Willam Nature Reserve will be the identified permanent water levels in the wetland.
At other times: These wetlands will service multiple purposes aligning with principles of integrated water management including:
- Stormwater harvesting of clean water for use in pubic open spaces. This is planned to be used in Bayside and Port Phillip.
- Biodiversity of plants for environmental benefits.
- Contamination / pollution reduction through the wetland system designed to deal with the invisible sources of contamination in the bay which are deadly to bay health.
We recognize that another issue for consideration is the visible litter & rubbish pollution and its control. We support the idea that this litter must be trapped in the street drains with litter baskets (prioritizing their inclusion in all shopping centres) and with Gross Pollution Traps in bigger drains as recommended by Melbourne Water. All of these options are costly to build and even more costly to maintain and can be significant impediments in full flood conditions. Public education programs and litter removal must also play its part as, once litter is in the drainage system, it is difficult to remove.
Members of PECAN have been continuously involved in this project since 2011. These members have been active throughout the process and strongly support the intentions of both projects. We salute the work done by Geoff Love (eFlag), who was tireless in his support of these endeavours until his death in 2022.
Roger Byrne (Former GHD Global Manager infrastructure Risk Management)
Helen Halliday OAM
26 February 2025